Use baking soda and vinegar to create an awesome chemical reaction! Watch as it rapidly fizzes over the container and make sure you’ve got some towels ready to clean up.
What you’ll need:
- Baking Soda (make sure it’s not baking powder)
- A container to hold everything and avoid a big mess!
- Paper towels or a cloth (just in case)
- Place some of the baking soda into your container.
- Pour in some of the vinegar
- Watch as the reaction takes place!
The baking soda (sodium bicarbonate) is a base while the vinegar (acetic acid) is an acid. When they react together they form carbonic acid which is very unstable, it instantly breaks apart into water and carbon dioxide, which creates all the fizzing as it escapes the solution.
For extra effect you can make a realistic looking volcano. It takes some craft skills but it will make your vinegar and baking soda eruptions will look even more impressive!
There’s some truth to this: advances in biology have frequently been driven more by technology than ideas about biology. For long time, many (not all, but many) answers to biological questions have been obvious once we have the technology to “just look at the thing.”
As a result, you have generations of biologists with little training in math, who approach their work primarily by intuitive reasoning about their system of interest. And of course you have some very clever, amazing technologies (developed by biologists as well as physicists).
Many of the fundamental questions that can be solved by just looking at things have been solved; as a result, a lot of biological research isn’t about fundamental questions – it’s about details, about how something works in a different cell type or a different organism, or at a different stage of embryonic development.
The result is that there is a growing recognition that there are important, remaining fundamental questions that can be solved by getting quantitative – by having more formal, mathematical ideas about biology. We can generate mountains of data, and we can do unbelievable, nano-scale experimental manipulations that Feynman would have loved, but do we know how to think about biology instead of technology?
Some of these important questions include how the structure of regulatory networks gives rise to the network dynamics: how do regulatory networks control gene expression in space and time? How do you get irreversible transitions in cell division or development? What types of structural features produce robust biological oscillators? How do regulatory pathways evolve – either adaptively or neutrally? How can we formally describe information transduction or processing inside of a cell in a way that leads to useful insights?
1. Microbes play defense. The oodles of microbes that live on and inside us protect us from pathogens simply by taking up space. By occupying spots where nasties could get access to and thrive, good microbes keep us healthy. As Eisen explains, “It’s sort of like how having a nice ground cover around your house can prevent weeds from taking over.”
2. Microbes boost the immune system. Researchers at Loyola University demonstrated in a 2010 study how Bacillus, a rod-shaped bacteria found in the digestive tract, bind to immune system cells and stimulate them to divide and reproduce. The research suggests that, years down the road, those with weakened immune systems could be treated by introducing these bacterial spores into the system. These microbes could potentially even help the body fight cancerous tumors.
3. Microbes protect us from auto-immune diseases. In his TEDTalk, Eisen describes being diagnosed with Type 1 Diabetes as a teenager after “slowly wasting away until I looked like a famine victim with an unquenchable thirst.” Because microbes help train the immune system, if the microbiome is thrown out of whack, it can alter the body’s ability to differentiate between itself and foreign invaders. Recent research into Type 1 Diabetes reveals that a disturbance in the microbial community could trigger the disease, in which the body kills cells that produce insulin. In a 2009 study, researchers at Cornell University showed that introducing a benign strain of E. coli into diabetic mice set off a domino effect that led them to produce insulin. The work suggests that, someday, microbial yogurt could replace insulin shots for people with the disease. Microbial disturbances could be at the root of other auto-immune disorders too.
4. Microbes keep us slim. Microbes play an important role in our body shape by helping us digest and ferment foods, as well as by producing chemicals that shape our metabolic rates. Eisen explains, “It seems that disturbances in our microbial community may be one of the factors leading to an increase in obesity.”
5. Microbes detoxify and may even fight off stress. Just as humans breath in oxygen and release carbon dioxide, microbes in and on us take in toxins and spare us their dangerous effects. A recent study also shows that people feeling intense stress have much less diverse bacterial communities in the gut, suggesting that there is a not-yet-understood interplay between microbes and stress responses.
6. Microbes keep babies healthy. Recent studies have shown that babies born via caesarean section have very different microbiomes than those born the old-fashioned way. Why? Because during the birthing process, babies are colonized with the microbes of their mother, especially substances that aid in the digestion of milk. According to Science News, babies born via C-section are more likely to develop allergies and asthma than children born vaginally.
1. The definition of “Miracle”
The problem I wish to investigate is the relation between science and religion, with a special focus on religion’s appeal to miracles. Let us define a “miracle” simply as an event which violates at least one law of nature. I realize that the term is used in other ways. For example, it is sometimes additionally required that miracles be caused by a supernatural being. For our purposes and in the interest of economy, that further requirement can be dispensed with. Alternatively, a miracle is sometimes taken to be any extraordinary event, particularly one that provides someone with a great benefit. That is certainly another use of the term in English, but not relevant to our topic, so let us disregard it. If we employ the definition initially given, that will allow us to focus on a particularly troublesome puzzle in the philosophy of science.
If miracles violate laws of nature, then they could never be explained by appeal to natural law. Note that it needs to be a genuine law of nature that is violated by a miracle, not a manmade generalization erroneously taken as a law of nature. This needs some clarification. By a law of nature I mean a proposition which describes an actual uniformity that obtains in our universe. An example would be the Archimedean Law that a floating body always displaces an amount of fluid the weight of which is equal to its own weight. And an example of a miracle which violates that law would be a man walking on water (thereby displacing an amount of fluid the weight of which would be considerably less than his own bodyweight). In science, events are explained naturalistically (i.e., by appeal to laws of nature), so a miracle would be an event that could never be explained in that way. But if events which cannot at present be explained in that way were to come to be explained naturalistically in the future, then, in retrospect, it would need to be said of them that they were never miracles, although they may at one time have (erroneously) been thought to be that. At the very least, the laws that miracles violate need to be genuine ones.
Consider an example. Centuries ago, it was regarded a law of nature that matter cannot be destroyed. Thus, an event like an atomic explosion, in which matter is destroyed, would at that time have been considered a miracle, for it violates the given law. But subsequent science came to abandon or amend the law in question in such a way that atomic explosions no longer violate natural law. A miracle, then, must be regarded, not as an event which violates current law (which may very well come to be superseded), but an event which violates one or more genuine laws, i.e., ones which can never be superseded by laws of nature which are more accurate and which cohere better with other parts of science.
What would be the status of laws of nature if miracles were actually to occur? First, would they cease to be genuine laws? If we say that a generalization that is violated by some event cannot be a genuine law of nature, then it would follow that miracles are logically impossible. That can be shown as follows:
(1) Miracles, by definition, are events which violate genuine laws of nature.
(2) If a generalization is violated by an event, then it cannot be a genuine law of nature.
(3) Thus, it is impossible for a genuine law of nature to be violated by any event. [from (2)]
(4) Hence, it is impossible for any event to be a miracle. [from (1) & (3)]
I think what we need to do here, to generate our philosophical issue, is to allow that it is at least logically possible for a law of nature to be violated. Let us therefore understand the concept of a law of nature in such a way that step (2) of the above proof is false. It may be that no laws of nature are ever violated, but there is no contradiction in the mere idea of it.
Another issue is that of truth. If a law of nature were to be violated, then could it still be true? One answer that might be given is: Yes, a violated law could still be true because laws of nature are only intended to describe events within the natural realm and miracles are outside the natural realm. Thus, miracles would not then render laws of nature false, for they would not show that the laws fail to correctly describe the natural realm. However, to view the matter in this way, the definition of “miracle” would need to be changed slightly. Instead of saying that miracles violate laws of nature, we would need to say that miracles are outside the natural realm and would violate laws of nature if they were in the natural realm. They would then not actually violate laws of nature, since laws of nature only describe events within the natural realm.
I do not like this way of viewing matters, because it places too much emphasis on the concept of a “natural realm.” To work with a definition of “miracles” as events outside the natural realm, we would need some criterion for deciding whether or not an event is inside or outside that realm, and we do not have any such criterion. The result would be that the term “miracle” would be obscure, perhaps even meaningless. Let us, therefore, simply go with our original definition of a miracle as an event which violates a law of nature. That results in the conclusion that if an miracle were to occur, then the law of nature which it violates would be false, since such a law would be a generalization with at least one exception to it. Thus, some laws would be false (namely, the ones violated by miracles) and other laws would be true (namely, those not violated by any miracles). This way of speaking, distinguishing true laws of nature from false ones, may sound rather peculiar, but there seems to be no other meaningful way to permit talk of miracles to enter the discussion. The idea of a law still being useful even though it is false is a familiar one. Newton’s Laws, for example, have been superseded in contemporary physics (and thus regarded as false), and yet they are still used in various practical fields. So, to speak of a law as false is not incoherent.
However, there is a problem here. Previously, a distinction was drawn between “genuine laws” and “erroneous (or superseded) laws.” How could that distinction still be drawn if we allow that even some of the genuine laws might be false? Let us say that if genuine laws are false, it is only because of isolated counter-instances which cannot be explained or predicted on the basis of any other empirical laws. But when erroneous (or superseded) laws are false, it is because of regular counter-instances which are both explainable and predictable on the basis of other empirical laws. Atomic explosions, for example, occur according to known regularities on the basis of which they could be explained and predicted. Thus, the law that matter cannot be destroyed is an erroneous (or superseded) one. But if a man were to walk on water, although that would make Archimedes’ Law false, it would not make it an erroneous law in the given sense. The counter-instance(s) would still be isolated and neither explainable nor predictable on the basis of any other empirical laws. Archimedes’ Law could still be a genuine law, though it would no doubt be somewhat suspect under such circumstances.
What would be the result if people walking on water were to become commonplace? Suppose various men were to do it every year, say, on Easter Sunday. Their action could not be explained by Archimedes’ Law, since the amount of fluid they displace as they walk on water does not correspond to a force sufficient to keep them from sinking. Some other force would be sought, but suppose that none is ever found and so their actions remain a mystery for science forever. Although such counter-instances to Archimedes’ Law would in that case not be isolated events, they would still be miracles if, indeed, the law cannot be replaced by other natural laws which are not violated by the given events. Thus, miracles need not be isolated events, but they do need to be events that violate natural law which are forever unexplainable within the system of science.
2. Scientists’ Attitudes
The philosophical issue which now comes into play is that of the relation between science and miracles (defined in the given way), particularly the attitude of scientists towards miracles. There seem to be at least the following possibilities:
(A) No scientist could ever believe in miracles under any circumstances.
(B) Scientists could believe in miracles, but not as scientists.
(C) Scientists could believe in miracles, even as scientists, but not when they are engaged in scientific research on the specific area in which the alleged miracles occur.
(D) Scientists, as scientists, could believe in miracles, even when engaged in scientific research on the specific area in which the alleged miracles occur, but such belief could not be regarded to be a result of the research or a scientific finding.
It seems clear that position (A) is incorrect, for there certainly have been scientists in the past who believed in miracles and there are still scientists today who do so (for example, many of those who identify themselves as Christians). But even if (A) is deleted, the question of which of the other positions is the correct one is rather difficult.
Certainly the last part of position (D) is correct. It could never be a scientific finding that a miracle occurred, for science is the attempt to understand reality in terms of the laws of nature. To say that a miracle occurred is to abandon the scientific (= naturalistic) perspective on the matter. If a scientist were to end up with such a belief, then it would be incompatible with the scientific point of view. It would be as if to say, “Here is something that could never be naturalistically explained and so it lies outside the domain of science.”
It might be objected here that the purpose of science is not to try to understand reality but only to predict it and thereby control it. That is, science is of significance only to the extent that it yields (or has the prospect of yielding) technological results. This is the pragmatic view of the nature of science. I don’t particularly care for it, since I find it too limited, but even if it were correct, it would still leave no room for any appeal to miracles within science. There is no way that an appeal to miracles could lead to theories which produce predictions or technological results. Thus, whether science is construed realistically or pragmatically, all appeals to miracles would be excluded from it.
But even if the last part of position (D), above, is correct, the first part of it may not be. It could be, instead, that (B) or (C) is the correct approach to take on this matter. Let us consider a hypothetical situation. Suppose a man is diagnosed with a terminal illness but then recovers fully. Such events have been known to happen and they are often termed “miracles.” Some medical researchers believe that miracles, of that sort, do indeed occur. One main question is whether, when they express such belief, they can do so as scientists, or whether they necessarily do so only as laypersons (or private citizens, as it is sometimes put).
According to position (D), it is indeed possible for medical researchers to believe, as scientists, that a miraculous cure has occurred. It is simply that they cannot put this down as a “scientific finding.” But it might be objected that if they cannot put the result down as a “scientific finding,” then when they claim that a miracle has occurred, they are not speaking as scientists at all. In order to speak as a scientist, one must be in a position to report a scientific finding, for the reporting of such findings is a major component of science. The first part of (D), therefore, conflicts with its last part, and so (D) needs to be rejected.
According to position (C), it would be possible for other scientists to claim, as scientists, that a miraculous cure has occurred, but not those scientists (medical researchers) who are engaged in the specific area of research in question. But that seems rather anomalous. Why should scientists who are outside a particular field be in any better position to speak in the name of science on a matter related to that field than those scientists who are working in the very field in question? It would seem more reasonable to say that the people best able to speak in the name of science on a particular area would be the very scientists who are working in that area. Position (C) has other difficulties as well, but this one seems sufficient to refute it.
By a process of elimination, only position (B) remains, and that is the one which I shall endorse. Scientists can claim that miracles occur, but when they do so, they do so only as laypersons, not as scientists. But what, then, are we to say about such persons? Their minds seem to be compartmentalized into at least a scientific part and a religious part. When they think in terms of their profession, they have a positive outlook on science, assuming that what it deals with is in principle explainable by appeal to natural law, but when they think religiously, they have a negative outlook on science, assuming that there are aspects of reality that can never be explained by appeal to natural law, no matter how far science advances.
Why would anyone assume that science has such limits? What possible evidence could there be that there are events which science will be forever unable to explain? The only possible evidence is that certain events have not as yet been given naturalistic explanations. However, many such events in the past later came to be explained naturalistically. Thus, the mere use of induction should lead us to infer that, eventually, the events presently unexplained may very well, and perhaps even probably will, be explained. It would seem, then, that the epistemic stance most compatible with a scientific way of thinking would be to withhold judgement on whatever events have not as yet been explained naturalistically. To reason that what has not as yet been explained can never be explained would be invalid. It would be a non sequitur (more specifically, a kind of hasty generalization). Furthermore, one should not adopt a pessimistic outlook on science by calling such events “miraculous,” for to do so would be not only unscientific, but anti-scientific as well.
Two points should be made regarding this matter. First, if there are scientists who have such a pessimistic (anti-scientific) outlook with regard to their own profession, then presumably they acquired it from religion, which partly regulates the early mental development of most children. There is certainly no scientific basis whatever for such pessimism. And, second, it may be that the belief in miracles is connected with the idea that there are aspects of reality which must be forever beyond scientific scrutiny. If one already believes that there are facts which it is impossible for science to explain, then one would be already predisposed towards a belief in miracles. Well, what sorts of facts might those be? Here are some possible candidates:
(A) Religious experiences in people
(B) Selfless love and sacrifice
(C) Objective values (e.g., morality)
(D) God and an afterlife
(E) Free will
(F) Mind or consciousness
(H) Basic uniformities of nature
(I) The fact that the uniformities permit life
(J) Laws of logic
(K) Abstract entities, like numbers
(L) The existence of the universe itself
(M) The fact that something exists
In each case, there are two questions: whether there is some fact there to be explained, and, if so, whether there is any hope that science might come up with a complete and adequate explanation of that fact. If, for some items on the list, the answers are “yes” and “no,” respectively, then that would predispose one towards a belief in miracles. That is, if there are other facts to be explained which science can’t possibly explain, then there is not so much involved in adding (the occurrence of) miracles to the list. I think that many of the items listed above are ones which religion appeals to as “facts beyond scientific explanation.” At any rate, if one is indoctrinated by religion to believe that there are such facts, then the acceptance of miracles would come easily. If the person should later adopt science as a profession, then the kind of compartmentalization of the person’s mind mentioned above would be an expected outcome.
It is an interesting question whether any items on the above list really have the features claimed for it by religion, that is: (1) a fact to be explained, and (2) forever incapable of any naturalistic explanation. I myself am inclined to deny it. For some of the items, it is condition (1) that fails to be met. I would say that of (C), (D), (J), (K), & (M). For all the other items, it is condition (2) that fails to be met: i.e., naturalistic explanations can be given. I shall not defend this here, for it is a large topic and beyond the scope of the present essay.
Perhaps the main question before us at this point is whether, within such mental compartmentalization as described above, the person necessarily holds incompatible beliefs. What it comes down to is the issue whether the scientist qua scientist must believe that all of reality is naturalistically explainable. If so, then scientists who believe in miracles would be inconsistent in their thinking.
We have already established that the scientist qua scientist cannot believe in miracles. But it is a further question whether he must deny that they ever occur. In other words, is the scientist qua scientist like an agnostic regarding miracles, neither believing in them nor denying them, or is he like an atheist, denying that they ever occur? If he is like an atheist, then for him to believe in miracles in some other compartment of his mind would be inconsistent, for it would contradict something that he believes in the scientific compartment. But if he is only like an agnostic, then there need be no such inconsistency. In his scientific compartment, there would (necessarily) be no belief in miracles, but there would not be anything that contradicts their occurrence either.
So, what is the answer? I argued above that when people work as scientists, they necessarily have a naturalistic worldview. But do they, in addition, necessarily believe that such a worldview is complete and not contradicted by anything else in reality? There are indeed scientists who do not regard the naturalistic worldview to be complete in that way. In their scientific work, they are only methodological naturalists and not also metaphysical naturalists. That is, they assume naturalism as an outlook presupposed by their scientific work, but they do not regard naturalism to be generally true of all reality. They might say, “I can make no reference to miracles here in science, but science is limited; there are aspects of reality that lie beyond it.” Are such scientists necessarily deficient as scientists? I shall make no pronouncement on this matter here but will leave it open. Certainly scientists who believe in miracles have compartmentalized minds, and some of the time (in their religious life) they have not only an unscientific but an anti-scientific outlook. But whether they must also have inconsistent beliefs is a further matter, one which I shall leave to the reader to judge.
Homo sapiens evolved about 200-150,000 years ago in Africa, but our story as a species stretches back much further than that with early human ancestors. And the evolution of Homo sapiens is itself a tangled tale, full of unanswered questions and gothic family melodrama. Here are a few facts you may not know about the human evolutionary story.
1. Early human beings left Africa over 1 million years ago
Most of us have heard the story about how Homo sapiens poured out of Africa into Europe and Asia starting about 80,000 years ago. What you may not realize is that our ancestor, Homo erectus, had been taking the same routes out of Africa on and off for over 1 million years. In fact, when Homo sapiens left Africa, they would have encountered other humans who looked very much like themselves – these would be the descendents of the common ancestor we share with Neanderthals, as well as the descendents of Homo erectus. All of these people were early humans. And they had been wandering around Eurasia for hundreds of thousands of years.
2. Humans have incredibly low genetic diversity
Humans are among the least genetically diverse apes, mostly because we all appear to be descended from a small group of humans who lived in East Africa. To describe genetic diversity, population geneticists use a measure called “effective population size.” Put extremely simply, effective population size is how many people you would need to reproduce the genetic diversity of our full population. For humans, this number hovers around 15,000 individuals, which is pretty insane when you consider our actual population size is 7 billion. As a point of comparison, some species of mice have an effective population size of 733,000.
3. You may be part Neanderthal
This is pretty widely known, but it bears repeating. Recent genetic analysis of Neanderthal bones reveals that there are some Neanderthal genes that have made their way into modern non-African populations. This suggests that when Cro-Magnons entered Europe, the Middle East and Asia, they probably had children with the local Neanderthal populations. We are all one happy human family.
4. The human population crashed about 80,000 years ago
Something mysterious happened about 80,000 years ago that reduced humanity’s effective population size. If you recall, the effective population size is not the same thing as the actual population size – it’s a measure of genetic diversity. So basically, our genetic diversity shrank by a lot 80,000 years ago. There are a lot of theories about why this might be, ranging from an apocalyptic disaster caused by the eruption of the Toba volcano, to something more mundane like interbreeding among small populations.
5. Humans navigated the Indian ocean in boats 50,000 years ago
Homo sapiens arrived in Australia roughly 50,000 years ago. How the hell did they get there from the shores of Africa? They used small boats, probably lashed together out of reeds. (Likely they were similar to the boats that brought us from Asia to the Americas over 17,000 years ago.) It was the Paleolithic equivalent of flying to the moon in a tin can. It shouldn’t have worked, but it did. Using those small boats, we crossed the Pacific many times and populated an entire continent.
6. Homo sapiens has only had a culture for less than 50,000 years
While we’re talking about all the cool things that happened 50,000 years ago, it’s worth noting that many anthropologists now believe early humans probably did not develop what we would recognize as culture until around that time. This is amazing when you consider that the “mitochondrial Eve” theory suggests that we are all descended from one East African woman who lived about 200-150,000 years ago. Given that Homo sapiens evolved around the time of mitochondrial Eve, that means our species hung around for a really long time before we developed awesome things like art, symbolic communication, ornaments, and fancy bone tools. Certainly, pre-cultural humans had fairly sophisticated toolkits and fire, but we have very little evidence that they had art and symbolic communication, which are the cornerstones of that thing we call “culture.” Some anthropologists believe that we didn’t even invent language until that cultural explosion, but this is almost impossible to prove one way or the other.
7. Homo sapiens has always used fire as a tool
Homo sapiens evolved after our ancestors tamed fire and started making tools. This sounds simple, but when you start to think about it, the implications are profound. As a species, we have never existed without one of the most important tools for building a civilization: tamed fire. As a species, we are born tool users and fire makers. Some might even say that means we were born cyborgs, because our species has always been augmented by the invention of artificially made fire and tools. Whoa.
8. Homo sapiens is still evolving rapidly
Good news, everyone! Homo sapiens is still evolving – and one day our progeny will be as different from us as we are from Homo erectus. Evolutionary biologists have isolated a few areas of the human genome that are under rapid selection. That means mutations in those genes are spreading rapidly throughout the population. Many of these mutations are related to brain size and development, and others have to do with our ability to tolerate certain kinds of foods (like dairy) and disease resistance. This has led some biologists to wonder whether we are evolving to be more intelligent, but it is not yet clear whether the evolutionary changes we are seeing have anything to do with intelligence — especially since our brains are actually shrinking. Still, it’s good to know that that the genes which control one of my favorite anatomical systems is still evolving.
Your brain is the most complex part of your body, it performs a large number of amazing calculations every second, taking in information from the outside world in the form of senses and allowing you to quickly respond to various situations. Use this senses lesson plan to show students some fun brain activities and teach them more about brain functions such as memory, taste, sight and touch.
It is said that as far back as 10000 years ago people had a strong awareness of the importance of the head and brain.
- The word ‘brain’ originated from the ancient Egyptians.
- Early philosophers such as Socrates and Aristotle wrote and made theories regarding the human brain although Aristotle also believed that the heart played a crucial role in human intelligence.
- The human brain interprets the world around us in many different ways. These processes are researched in the study of neuroscience.
- Can you name some of the ways that humans process information from the world around us? Memory, reflexes, senses etc.
- If you have access to old human and animal skulls they are great for giving a physical perspective. Ask the students for any differences or similarities they notice between them. Good posters and images are also useful, you explain what scientists already know about the human skull and brain.
Physical differences in the brain of different species go much deeper than the obvious size and shape aspects, feel free to discuss more about this, the senses and brain functions in general.
- Another way that our brains make assumptions is through optical illusions. Our brain tries to fill in the gaps, especially as we have been taught to use specific shapes and angles to tell us about size. Your brain is always looking for blank spaces and filling them with information. Our brains are always trying to recognise things in our environment and create meaning out of them. It is part of our survival instinct. Sometimes your brain leaps to the wrong conclusion and you get a surprise. Magicians and illusionists are experts at using this to their advantage.
- Show the students a colored jellybean, red for example. They have to guess what flavour it might be. After they have guessed, give them all one of these jellybeans and see if they were right. Talk to them about how our brain sometimes makes assumptions about certain things that we have a memory of.
- Test the short term memory of the students. Show them a number of different objects and tell them to remember as many as possible. They have only one minute to look at them. Hide the objects after one minute has passed. Let the kids write down as many things as they can remember on a sheet of paper. Can they remember all of the items? Are there any that were forgotten by everyone? What could they do to improve their memory?
What areas of our bodies are most sensitive to touch? Our Hands? Feet? Fingers?
- Bend a paper clip into the shape of a U with the tips about 2 cm apart. Make sure the tips of the U are evenly aligned with each other.
- Lightly touch the two ends of the paper clip on the back of your partners hand. Your partner should not be looking as you do this. Do not press to hard!
- Try and make sure that both tips touch the skin at the same time. Ask your partner if they felt one or two pressure points.
- If your partner felt one point, spread the tips of the clip a bit further apart, then touch the back of your partners hand again. If your partner felt two points, push the tips a bit closer together and test again.
- Measure the distance at which your partner can feel two points.
- Now try the same thing on different parts of the body and record the distances.
The receptors in our skin are not distributed in a uniform way around our body. Some places, such as our finger and lips, have more touch receptors than other parts of our body, such as our backs. That is one reason why we are more sensitive to touch on our fingers and face than on our backs.
Crystallography is the study of atomic and molecular structure. Crystallographers want to know how the atoms in a material are arranged in order to understand the relationship between atomic structure and properties of these materials. They work in many disciplines, including chemistry, geology, biology, materials science, metallurgy and physics. Crystallographers study diverse substances, from living cells to superconductors, from protein molecules to ceramics.
Crystallography began with the study of crystals, like quartz. Today, crystallographers study the atomic architecture of any material that can form an orderly solid – from diamonds to viruses. They also investigate a wide variety of other materials, such as amorphous thin films, membranes, liquid crystals, fibers, glasses, liquids, gases and quasicrystals.
Because many crystallographers use x-rays to study crystals, the field is often called “x-ray crystallography.” But modern crystallographers use many other methods as well. Atomic force microscopy, neutron diffraction, electron crystallography, molecular modeling, high- and low-temperature studies, high-pressure diffraction and micro-gravity experiments in space are all methods used by crystallographers to unlock the secrets of structure and function.
Crystallographers at Work
Two familiar materials, diamond and graphite, provide an easy example of how the arrangement of atoms determines the characteristics of a material. Both diamonds and graphite are composed entirely of carbon atoms. A diamond is one huge molecule, very hard, with a very high melting point. By contrast, the carbon atoms in graphite are arranged in layers of flat hexagons which can slide relative to each other, so graphite is the soft, greasy material used in pencils and lubricants. Excitement was high when scientists recently discovered a new all-carbon chemical, with each molecule consisting of sixty carbon atoms. The crystal structure of “C60”, shown here1 looks like a geodesic dome or soccer ball. Scientists are enthusiastically investigating the unusual electrical, magnetic and chemical properties of these tiny soccer balls.
The three-dimensional shape of a molecule relates to how the molecule will work – in a chemical reaction in the laboratory, or in a cell in your body. Once the relationship between the structure and properties is understood, it is often possible to design new materials, such as plastic, drugs, alloys, and superconductors, which have specific desired properties. For instance, crystallographers found that, in its crystal form, coenzyme B12 has a very long chemical bond (on a molecular scale) between the central cobalt and the carbon atom. This located a weak, reactive part of the molecule, where a free radical reaction is initiated when the bond breaks. (2) With this knowledge, other scientists may be able to develop new catalysts to speed up the chemical reaction.
A precise fit between two molecules is often the requirement for a reaction. Crystallographers have recently discovered how proteins recognize the shape of DNA to turn genes on and off. (3) With information like this, other scientists may design drugs to control blood pressure, inhibit the growth of the AIDS virus, or cure the common cold.
Image 2: Crystal structure of a protein which regulates DNA. Two gray helical ribbons represent the DNA; cylinders outline the protein ÿ-helices; the dark lines show bonds between atoms in an important part of the protein which makes specific contacts to the DNA.
Liquid crystals are sometimes described as the “fourth state of matter.” The molecules in liquid crystals are arranged in an orderly, periodic way, but these materials are fluid, like a liquid. Using diffraction techniques, polarizing microscopy and/or nuclear magnetic resonance (NMR), crystallographers can determine the approximate arrangement of molecules in liquid crystals. They have also studied transitions between liquid crystalline phases in real time using synchrotron x-ray sources. There is still a great deal that we do not understand about these novel materials.
Image 3: A schematic cartoon showing one possible arrangement of molecules in a liquid crystal. Ovals represent the polar head group and “tails” the hydrocarbon chain. (4)
Quasicrystals are crystals with quasi-periodic order. They might also be described as impossible crystals. The molecules in some quasicrystals are arranged about an axis of 5-fold symmetry. Traditionally, crystallographers have considered this to be impossible since there is no strictly periodic way to make this arrangement work. (Try covering your floor with tiles shaped like regular pentagons. Your pattern will show gaps or overlaps!) Nevertheless, there are crystals that have 5 fold external symmetry and display 5-fold (or 10-fold) diffraction symmetry (when x-rays are passed through them). These structures pose a great challenge to crystallographers.
In chemistry, biology and materials science – anywhere atomic structure is the key to understanding and controlling chemical and physical properties – crystallographers are making fundamental discoveries and exciting advances.
Biophysics is a bridge between biology and physics.
Biology studies life in its variety and complexity. It describes how organisms go about getting food, communicating, sensing the environment, and reproducing. On the other hand, physics looks for mathematical laws of nature and makes detailed predictions about the forces that drive idealized systems. Spanning the distance between the complexity of life and the simplicity of physical laws is the challenge of biophysics. Looking for the patterns in life and analyzing them with math and physics is a powerful way to gain insights.
Biophysics looks for principles that describe patterns. If the principles are powerful, they make detailed predictions that can be tested.
What do biophysicists study?
All of Biology is Fair Game.
Biophysicists study life at every level, from atoms and molecules to cells, organisms, and environments. As innovations come out of physics and biology labs, biophysicists find new areas to explore where they can apply their expertise, create new tools, and learn new things. The work always aims to find out how biological systems work. Biophysicists ask questions, such as:
How do protein machines work? Even though they are millions of times smaller than everyday machines, molecular machines work on the same principles. They use energy to do work. The kinesin machine shown here is carrying a load as it walks along a track. Biophysics reveals how each step is powered forward.
How do systems of nerve cells communicate? Biophysicists invented colored protein tags for the chemicals used by cells. Each cell takes on a different color as it uses the tagged chemicals, making it possible to trace its many pathways.
How do proteins pack DNA into viruses? How do viruses invade cells? How do plants harness sunlight to make food?
Biophysics studies life at every level, from atoms and molecules to cells, organisms, and environments.
How essential is biophysics to progress in biology?
Biophysics discovers how atoms are arranged to work in DNA and proteins.
Protein molecules perform the body’s chemical reactions. They push and pull in the muscles that move your limbs. Proteins make the parts of your eyes, ears, nose, and skin that sense your environment. They turn food into energy and light into vision. They are your immunity to illness. Proteins repair what is broken inside of cells, and regulate growth. They fire the electrical signals in your brain. They read the DNA blueprints in your body and copy the DNA for future generations.
Biophysicists are discovering how proteins work. These mysteries are solved part by part. To learn how a car works, you first need to know how the parts fit together. Now, thanks to biophysics, we know exactly where the thousands of atoms are located in more than 50,000 different proteins. Each year, over a million scientists and students from all over the world, from physicists to medical practitioners, use these protein structures for discovering how biological machines work, in health and also in diseases.
Variations in proteins make people respond to drugs differently. Understanding these differences opens new possibilities in drug design, diagnosis, and disease control. Soon, medicines will be tailored to each individual patient’s propensity for side effects.
Biophysics revealed the structure of DNA
Experiments in the 1940’s showed that genes are made of a simple chemical–DNA. How such a simple chemical could be the molecule of inheritance remained a mystery until biophysicists discovered the DNA double helix in 1953.
The structure of DNA was a great watershed. It showed how simple variations on a single chemical could generate unique individuals and perpetuate their species.
Biophysics showed how DNA serves as the book of life. Inside of cells, genes are opened, closed, read, translated, and copied, just like books. The translation leads from DNA to proteins, the molecular machinery of life.
During the 2000’s, biophysical inventions decoded all the genes in a human being. All the genes of nearly 200 different species, and some genes from more than 100,000 other species have been determined. Biophysicists analyze those genes to learn how organisms are related and how individuals differ.
Discoveries about DNA and proteins fuel progress in preventing and curing disease.
What are the applications?
Biophysics is a wellspring of innovation for our high-tech economy. The applications of biophysics depend on society’s needs. In the 20th century, great progress was made in treating disease. Biophysics helped create powerful vaccines against infectious diseases. It described and controlled diseases of metabolism, such as diabetes. And biophysics provided both the tools and the understanding for treating the diseases of growth known as cancers. Today we are learning more about the biology of health and society is deeply concerned about the health of our planet. Biophysical methods are increasingly used to serve everyday needs, from forensic science to bioremediation.
Biophysics gives us medical imaging technologies including MRI, CAT scans, PET scans, and sonograms for diagnosing diseases.
It provides the life-saving treatment methods of kidney dialysis, radiation therapy, cardiac defibrillators, and pacemakers.
Biophysicists invented instruments for detecting, purifying, imaging, and manipulating chemicals and materials.
Advanced biophysical research instruments are the daily workhorses of drug development in the world’s pharmaceutical and biotechnology industries. Since the 1970’s, more than 1500 biotechnology companies, employing 200,000 people, have earned more than $60 billion per year.
Biophysics applies the power of physics, chemistry, and math to understanding health, preventing disease and inventing cures.
Why is biophysics important right now?
Society is facing physical and biological problems of global proportions. How will we continue to get sufficient energy? How can we feed the world’s population? How do we remediate global warming? How do we preserve biological diversity? How do we secure clean and plentiful water? These are crises that require scientific insight and innovation. Biophysics provides that insight and technologies for meeting these challenges, based on the principles of physics and the mechanisms of biology.
Biophysics discovers how to modify microorganisms for biofuel (replacing gasoline and diesel fuel) and bioelectricity (replacing petroleum products and coal for producing electricity).
Biophysics discovers the biological cycles of heat, light, water, carbon, nitrogen, oxygen, heat, and organisms throughout our planet.
Biophysics harnesses microorganisms to clean our water and to produce lifesaving drugs.
Biophysics pushes back barriers that once seemed insurmountable.
In case you were wondering, at last count 1,659,420 species of animals have been described by scientists. Nearly 80% of those are arthropods, or insects and their crunchy relatives.
Our Planet of the Arthropods is dominated by insects, and when and how insects took over the earth is a question that’s puzzled naturalists for centuries. In an incredible international effort, 100 scientists combined their molecular, computational biology, statistics, paleontology, and taxonomic expertise to uncover some surprising conclusions about when major groups of insects evolved:
B. Misof, et al. 2014. Phylogenomics resolves the timing and pattern of insect evolution. Science 346 (6210): 763-767.
How do you solve a problem like the insects?
The back story of this research is almost as interesting as the results. Making sense of the diversity of insects in collections has traditionally been a task for a lone expert, usually specializing in just one subset of a group. They become so identified with their study organisms, they may be introduced as “The Ant Man” or “The Wasp Woman.” (No taxonomists I know wear spandex tights and capes to work, for which I am profoundly grateful.) With over a million described species, it’s not hard to see how someone might spend an entire life trying to make order out of biodiversity chaos.
Taxonomy has a history of conflict and eccentricity, and the entry of new molecular technologies into the world of tiny pins and museum specimens hasn’t always been smooth. When sequencing was expensive and time consuming, the question was “which species should we do next?” Competition for funding and lab space was brisk.
With advances in both computing and Next-Generation sequencing, the speed and cost of sequencing dropped enough that scientists can band together and ask bigger questions. Brian Wiegmann of North Carolina State University (Author #74) put this elegantly: “It’s not enough to just catalog the books in the library; we want to understand their contents.”
Bernhard Misof from the Zoological Research Museum Alexander Koenig, Germany (Author #1), Xin Zhou from the China National GeneBank, BGI-Shenzhen, China (Author #100), and Karl Kjer from Rutgers University, USA (Author #99), came up with an ambitious plan. They formed 1KITE; the acronym stands for 1K Insect Transcriptome Evolution. A global crew of experts was recruited to help create an open-access inventory of transcriptomes (all expressed genes in an organism) for 1,000 insect species. This database will be used to answer questions about how insects evolved into the amazing diversity of forms we see today, and also has applications in medicine, agriculture, and conservation ecology.
The paper released this week deals mostly with the timing of insect evolution, based on a subset of 144 species. The researchers are looking for answers to some very big questions: When did insects evolve flight? When did the amazing diversity of insects develop?
Clocks and Rocks
The problem with fossils is they are rare. When you have tiny squishy animals involved, they are even less common. This new research uses time estimates based on geological evidence from fossils in combination with estimated times of divergence based on molecular evidence. This is sometimes called a molecular clock, since it uses accumulated changes in DNA to tell how much time has passed.
Looking at all the RNA in thousands of insect samples in hundreds of species of insects is a LOT of data. The biggest problem for the project was dealing with the massive amount of sequence information generated. The possible combinations were in the quadrillions. The computing capacity to crunch all that data…doesn’t exist.
This is where computer scientist and bioinformatics expert Alexandros Stamatatakis (Author #60) and his team came into play. His research group came up with a mathematical method to exclude highly unlikely combinations, and focus on likely ones. The Heidelberg Institute for Theoretical Studies Supercomputer group, which usually works on astrophysics problems, was used to crunch the data.
Dinosaurs did not have lice, and other revelations
So what did this tremendous amount of work find? The conclusion I think will stir up the most public attention is that lice are a recent group of insects, appearing only about 53 million years ago; the time that modern birds and mammals showed up.
This date makes lice “younger” than primates. There may be a bit of a kerfuffle as previous lousy estimates based on fossils are revised. Everyone loves a good taxonomic throwdown.
But that is really a secondary finding. Other major findings of note:
- Insect ancestors (Hexapoda) likely originated during the Early Ordovician Period, about 479 million years ago.
- Insect flight emerged around 406 million years ago, around the same time plants began to really diversify on land and grow upward into forests.
- The explosive diversification of insects into most of the major orders we see today happened before the emergence of Angiosperms (flowering plants).
Just how very fast insects diversified is remarkable. The earth is ~4.5 billion years old. In just the last 10% of earth’s history, plants colonized the land. In a span of 80 million years insects formed most of the major groups still alive today and took over the skies, where they reigned supreme for millennia.
Jessica Ware of Rutgers University (Author #8) said “it was a rapid and extreme radiation in a very short period of time. It made our job really hard as scientists–that’s been one of the traditional stumbling blocks for classifying insects. With this huge amount of data we now have excellent resolution, and we can actually say something about age ranges.”
What Does It All Mean?
The best part of this research is yet to come, but where we are headed is clear. The Insect tree of life has been pruned and re-arranged constantly in the last century. It sometimes feels like taxonomists have been participating in an FBI witness-protection program, the names have been changed so often.
That will certainly continue — understanding how each group of beetles, for example, is related is a very fine level of detail. But the bigger picture is finally coming into focus. We now are on track to a real phylogeny, or map of what came first, and what relationship groups have with each other. This group is a parent, this group is a sister.
As more of the research from this group is published, we are getting closer to a phylogeny of insects that is more than just a story that we pieced together from wing patterns and bug genitals. We are truly beginning to realize what a great beetle collector once said:
Iron is one of the elements highlighted in the Quran. In the chapter known Al-Hadeed, meaning Iron, we are informed:
“And We also sent down iron in which there lies great force and which has many uses for mankind…” (Quran 57:25)
The word “anzalna,” translated as “sent down” and used for iron in the verse, could be thought of having a metaphorical meaning to explain that iron has been given to benefit people. But, when we take into consideration the literal meaning of the word, which is, “being physically sent down from the sky, as this word usage had not been employed in the Quran except literally, like the descending of the rain or revelation, we realize that this verse implies a very significant scientific miracle. Because, modern astronomical findings have disclosed that the iron found in our world has come from giant stars in outer space.
Not only the iron on earth, but also the iron in the entire Solar System, comes from outer space, since the temperature in the Sun is inadequate for the formation of iron. The sun has a surface temperature of 6,000 degrees Celsius, and a core temperature of approximately 20 million degrees. Iron can only be produced in much larger stars than the Sun, where the temperature reaches a few hundred million degrees. When the amount of iron exceeds a certain level in a star, the star can no longer accommodate it, and it eventually explodes in what is called a “nova” or a “supernova.” These explosions make it possible for iron to be given off into space.
One scientific source provides the following information on this subject:
“There is also evidence for older supernova events: Enhanced levels of iron-60 in deep-sea sediments have been interpreted as indications that a supernova explosion occurred within 90 light-years of the sun about 5 million years ago. Iron-60 is a radioactive isotope of iron, formed in supernova explosions, which decays with a half life of 1.5 million years. An enhanced presence of this isotope in a geologic layer indicates the recent nucleosynthesis of elements nearby in space and their subsequent transport to the earth (perhaps as part of dust grains).”
All this shows that iron did not form on the Earth, but was carried from Supernovas, and was “sent down,” as stated in the verse. It is clear that this fact could not have been known in the 7th century, when the Quran was revealed. Nevertheless, this fact is related in the Quran, the Word of God, Who encompasses all things in His infinite knowledge.
The fact that the verse specifically mentions iron is quite astounding, considering that these discoveries were made at the end of the 20th century. In his book Nature’s Destiny, the well-known microbiologist Michael Denton emphasizes the importance of iron:
“Of all the metals there is none more essential to life than iron. It is the accumulation of iron in the center of a star which triggers a supernova explosion and the subsequent scattering of the vital atoms of life throughout the cosmos. It was the drawing by gravity of iron atoms to the center of the primeval earth that generated the heat which caused the initial chemical differentiation of the earth, the outgassing of the early atmosphere, and ultimately the formation of the hydrosphere. It is molten iron in the center of the earth which, acting like a gigantic dynamo, generates the earth’s magnetic field, which in turn creates the Van Allen radiation belts that shield the earth’s surface from destructive high-energy-penetrating cosmic radiation and preserve the crucial ozone layer from cosmic ray destruction…
“Without the iron atom, there would be no carbon-based life in the cosmos; no supernovae, no heating of the primitive earth, no atmosphere or hydrosphere. There would be no protective magnetic field, no Van Allen radiation belts, no ozone layer, no metal to make hemoglobin [in human blood], no metal to tame the reactivity of oxygen, and no oxidative metabolism.
“The intriguing and intimate relationship between life and iron, between the red color of blood and the dying of some distant star, not only indicates the relevance of metals to biology but also the biocentricity of the cosmos…”
This account clearly indicates the importance of the iron atom. The fact that particular attention is drawn to iron in the Quran also emphasizes the importance of the element.
Moreover, iron oxide particles were used in a cancer treatment in recent months and positive developments were observed. A team led by Dr. Andreas Jordan, at the world famous Charité Hospital in Germany, succeeded in destroying cancer cells with this new technique developed for the treatment of cancer—magnetic fluid hyperthermia (high temperature magnetic liquid). As a result of this technique, first performed on the 26-year-old Nikolaus H., no new cancer cells were observed in the patient in the following three months.
This method of treatment can be summarized as follows:
1. A liquid containing iron oxide particles is injected into the tumour by means of a special syringe. These particles spread throughout the tumour cells. This liquid consists of thousands of millions of particles, 1,000 times smaller than the red blood corpuscles, of iron oxide in 1 cm3 that can easily flow through all blood vessels.
2. The patient is then placed in a machine with a powerful magnetic field.
3. This magnetic field, applied externally, begins to set the iron particles in the tumour in motion. During this time the temperature in the tumour containing the iron oxide particles rises by up to 45 degrees.
4. In a few minutes the cancer cells, unable to protect themselves from the heat, are either weakened or destroyed. The tumour may then be completely eradicated with subsequent chemotherapy.
In this treatment it is only the cancer cells that are affected by the magnetic field, since only they contain the iron oxide particles. The spread of this technique is a major development in the treatment of this potentially lethal disease. Iron has also been found to be a cure for people suffering from anemia. In the treatment of such a widespread diseases, the use of the expression “iron in which there lies great force and which has many uses for mankind” (Quran, 57:25) in the Quran is particularly noteworthy. Indeed, in that verse, the Quran may be indicating the benefits of iron even for human health. (God knows best.)
- The magnification of a light microscope is found by multiplying the separate magnifications of its objective and eyepiece lenses.
- The maximum useful magnification of a microscope depends on its resolving power.
- The resolution of a microscope is its ability to distinguish two close structures as separate objects.
- An electron microscope has a higher resolution than a light microscope and so it can be used at a higher magnification.
- The resolution of an electron microscope is due to the shorter wavelength of its electron beam compared to light.
- Staining allows cell structures to be distinguished.
- e cells. Explain that these reactions are what keep an organism alive, and when a body’s chemistry does not function as it should, the organism becomes ill. Cite cancer as an example of an illness caused by malfunctioning enzymes. Point out that this illustrates how chemistry and biology are closely interrelated.
- Teach students that neither cells nor their components are stationary. Molecules within cells that interact to keep the cell functioning must move around, which requires force. Bacteria or viruses moving through the bloodstream and sperm also use force. Biologists study these movements in terms of force-velocity, making biology overlap with physics.
- Ask students to research other areas where biology, chemistry and physics interconnect. For example, they may investigate current studies on organism development, exploring whether cells respond more to physical cues, such as the stiffness of their surrounding environment, or to chemical cues, such as the diffusion rate of enzymes.
- Reinforce these concepts by assigning homework that requires chemical formulas or physics equations. For example, students can chart the process of metabolism in terms of chemical processes.