World-Changing Science Experiments: Part One

Full Transcript

Announcer: Welcome to Stuff From the Science Lab, from

Allison Loudermilk: Hey, guys, and welcome to the podcast. This is Allison Loudermilk, the science editor at

Robert Lamb: And this is Robert Lamb, science writer at

Allison Loudermilk: Today we're going to talk about a couple of experiments that have perhaps changed the world.

Robert Lamb: Yeah, these are pretty big ones.

Allison Loudermilk: Yeah. So worldwide, billions and billions of dollars are earmarked for scientific research and development. I looked this up. It turns out in 2009 the United States government allotted $114 billion just for research and development awarded to its agencies, so the various government agencies, as you can imagine.

Robert Lamb: Yeah. I think that the dude in the Riddler costume on those infomercials told me this.

Allison Loudermilk: Yeah. A lot of that money went to the Department of Defense, as you might -

Robert Lamb: Yeah, it always helps if you can kill somebody with your science experiment.

Allison Loudermilk: No doubt. Then a little less than half of that was split between basic research, the kind that's driven by scientific curiosity or interesting in a particular scientific question, and then applied research, the kinda research that's designed to solve practical problems, right.

Robert Lamb: Yeah. Some of the stuff that goes on is just really cool. I was doing a news article several months back about research into how hammerhead sharks see. The U.S. government was flipping the bill for a lot of that and I have yet to come up with a way that that could be used to kill somebody or really do anything other than understand hammerheads.

Allison Loudermilk: Right. So I was bringing up those numbers just to illustrate how many experiments are going on right now, a lot of which we will never, ever know about, a lot of which won't get picked in the New England Journal of Medicine. So we decided to highlight a few that particularly stand out. So we're doing a series, a two-part series in which we highlight a couple of our favorite experiments with the big guns here. We're talking -

Robert Lamb: Yeah. Our first one is Darwin.

Allison Loudermilk: I should mention, in a few instances, we're going to talk about two closely related experiments as opposed to one single experiment, just because, as you guys know, science stands on the shoulder of giants. It's hard to sometimes separate out who did what when.

Robert Lamb: Sometimes it's like a short person standing on the shoulder of a giant, then, there's another giant standing on top of the short person, but if you took the short person out of the mix, then it all falls apart. It's like Jenga.

Allison Loudermilk: That's true, that true.

Robert Lamb: With feet.

Allison Loudermilk: Except Jenga with giants.

Robert Lamb: Yeah.

Allison Loudermilk: Right. So who's the first nominee?

Robert Lamb: Charles Darwin.

Allison Loudermilk: All right, let's talk about Darwin.

Robert Lamb: Darwin's flowers.

Allison Loudermilk: Don't you mean Darwin's Galapagos Islands trip? No, you don't; you mean flowers.

Robert Lamb: No, that was - this kinda came later. The Galapagos Islands trip is famous because he was always looking at birds and he was really putting together all the data that would lead to origin of species. After all that, it's, like, the theory is out there, and it's not popular with everybody. It still needs a lot of support. He has his supporters, but there's also plenty of people making funny of him and drawing really mean cartoons.

Allison Loudermilk: It was divisive.

Robert Lamb: Yeah, he was a divisive character for sure.

Allison Loudermilk: And he didn't want to be, actually.

Robert Lamb: No, he hated it. We have, I think, a really good article on the man.

Allison Loudermilk: Conveniently, you wrote it.

Robert Lamb: Yeah, I wrote that one. But, no, he was having to - he retreated from the public eye and let other people handle the PR stuff, and he went back to experiments.

Allison Loudermilk: Smart move, Darwin.

Robert Lamb: Yeah.

Allison Loudermilk: So what did he do?

Robert Lamb: Well, he started looking into orchids and their pollinators.

Allison Loudermilk: So he was looking to reinforce his theory of natural selection?

Robert Lamb: Right. This boils down to - I mean, you look at some of the crazy orchids and flowers out there, and there's such a variety of design in them. Somewhere out there in the world, there's an insect that's custom-evolved to pollinate that one particular flower.

Allison Loudermilk: Right, that was his thought.

Robert Lamb: Yeah, that was his thought. So he started - if he were around today, he's make a spreadsheet of this. Which flowers line up with which pollinators?

Allison Loudermilk: Right. Take the Star of Bethlehem orchid, for example. It's an orchid that stores nectar near the bottom of a tube up to 12 inches long. Darwin saw this design and he predicted that there was a matching animal out there.

Robert Lamb: Yeah, somewhere out there in the world there's one insect that's made to take care of this.

Allison Loudermilk: So sure enough, in 1903, scientists discovered that the hawk moth sported a long proboscis, or nose, essentially, uniquely suited to reach the bottom of this particular orchid's nectar tube. So this was good because, again, it was providing evidence for his theory of natural selection. It was giving credence on the origin of species and just generally bolstering the modern framework of evolution as we know it, with flowers.

Robert Lamb: Yeah.

Allison Loudermilk: So let's do another biology one. Let's talk about DNA.

Robert Lamb: Oh, yeah, this is a big one as well. Watson and Crick, right?

Allison Loudermilk: Yeah. Well, Watson and Crick had all the headlines, and lots of school kids certainly know James Watson and Francis Crick as the guys who unlocked the mystery of DNA, but there were a whole lot of other players involved in the mix. So that 1962 Nobel Prize in Medicine was split among Watson, Crick, and Maurice Hugh Wilkins. These are the guys who figured out the molecular structure of DNA, along with the help of more than a few scientists like -

Robert Lamb: - Hershey and Chase.

Allison Loudermilk: Right. So back in 1952, Alfred Hershey and Martha Chase were conducting this now famous blender experiment that identified DNA as the molecule responsible for heredity. That's no small feat. Hershey and Chase's research prompted a bunch of scientists to decipher DNA's molecular structure. It was just like this scientific sorta gold rush. Instead of focusing on gold, they were focusing on deoxyribonucleic acid.

Robert Lamb: I like to think that each duo of scientists was like a cop duo, where one was the good cop and one was the bad cop. So Watson and Crick, one's taking the strong arm with the DNA and the other's bringing him coffee.

Allison Loudermilk: Did you ever see the TV movie about this, The Race for the Double Helix, a.k.a. Life Story?

Robert Lamb: No. Who was in that?

Allison Loudermilk: It was a BBC production. I'm surprised you have not seen it because Jeff Goldblum is in it.

Robert Lamb: Whoa, really? Oh, man, I bet he's awesome and a little crazy in it.

Allison Loudermilk: Yeah. I forget which one he was, Watson or Crick, but I must have seen that back in the day because, whenever I think of DNA and stuff, I always think of Goldblum, and I could never think why, and now I know. It was, in fact, this movie.

Robert Lamb: Are you sure you weren't thinking about -

Allison Loudermilk: - The Fly?

Robert: - The Fly because there's a lot of DNA stuff in there.

Allison Loudermilk: Right, right. The Fly and The Race for the Double Helix.

Robert Lamb: That's the movie I base my understanding of DNA on.

Allison Loudermilk: So prizewinner Wilkins, along with his colleague, Rosalind Franklin, who did not win the DNA Nobel Prize - which is a whole separate but interesting story - used this technique called X ray diffraction to study DNA. We're going to talk about this technique a little later on too, with you, Robert, right?

Robert Lamb: Yeah.

Allison Loudermilk: So the technique basically involves shooting X-rays at, in this case, aligned fibers of purified DNA.

Robert Lamb: Yeah. The idea is, when X-rays travel through something -

Allison Loudermilk: They're going to get diffracted or bent, right.

Robert Lamb: Yeah, they come out the other side, but they get diffracted, they get moved around, and they can tell you what it just passed through. It's kinda like when you - this is a very broad example, but it's like when you get an X-ray made of your tooth at the dentist's office, or in a back alley. The X-rays pass through your teeth and onto that little film, right. So then they -

Allison Loudermilk: - give you information about what's going on in your mouth.

Robert Lamb: Yeah, they give you information about what happened between -

Allison Loudermilk: Eight cavities.

Robert Lamb: Exactly, yeah.

Allison Loudermilk: So yeah, in this case, the diffracted X-rays form a pattern that's unique to the molecule in question and, in this case, it was DNA. So Rosalind Franklin's now famous photo of DNA shows this X shaped pattern. Of course, you have to know how to interpret that pattern to, quote/unquote, "see the molecule," and Watson and Crick did.

So Watson and Crick knew that the photo represented the signature of a helical molecule. They also figured out the width of the helix by analyzing Franklin's image, and DNA was somewhat decoded.

Robert Lamb: Yeah, the rest is history, and we have the image of the double helix everywhere.

Allison Loudermilk: And we fully understand everything that DNA can do now, right?

Robert Lamb: Yeah, we got it licked.

Allison Loudermilk: We've got it down. So let's look at another world-changing biology type experiment that we like.

Robert Lamb: Oh, yeah, yeah. This one's really cool. This one has to do with vaccinations and the eradication of small pox.

Allison Loudermilk: Okay. Right, so until recently, a small pox was a pretty serious public health problem.

Robert Lamb: Right. So then there was this British physician by the name of Edward Jenner. Around 1796, he started noticing that dairy maids would catch something called cow pox.

Allison Loudermilk: What is Jenner doing noticing the dairy maids is one question.

Robert Lamb: Well, they're -

Allison Loudermilk: - probably pretty cute.

Robert Lamb: Yeah, they're pretty cute gals, and they were catching some sort of a pox, this cow pox, from the cows, and they suffered through that. But then after they've had cow pox, they're immune to small pox.

Allison Loudermilk: Really?

Robert Lamb: Yeah. So he started studying this phenomenon, hanging out with more and more dairy maids.

Allison Loudermilk: You know cow pox is still around. So is beaver pox.

Robert Lamb: I have not heard of beaver pox.

Allison Loudermilk: I just made that one up, I'm kidding. There's no beaver pox.

Robert Lamb: So eventually, Jenner decided to see if he could transfer immunity to small pox by infecting someone with cow pox on purpose. So he found this little boy by the name of James Phipps.

Allison Loudermilk: Okay. What did James Phipps' parents make of this, by the way? Those were kinda the good old days of human experimentation.

Robert Lamb: Yeah because, I mean, it gets kinda grim. The way he decided to essentially vaccinate him, although he didn't really know if it was going to work - it was still an experimental phase - he made cuts on the boy's arms and then inserted some fluid from the cow pox sores of a local dairy maid that he was hanging out with named Sarah.

Allison Loudermilk: Sarah Nelmes.

Robert Lamb: Yeah. So the kid contracted the cow pox and then recovered, and

was then immune to small pox.

Allison Loudermilk: Right. So 48 days later, Jenner said, "Okay, you had your cow pox cuts. Let's see what you're going to do with small pox." Sure enough, he exposed him and he found out that the boy was immune, proving Jenner's theory correct.

Robert Lamb: Fast forward a little while and there's no more - and then you have a powerful small pox vaccine going on.

Allison Loudermilk: Pretty cool. So let's talk a little chemistry, although the scientist at the center of our next experiment considered himself a physicist, not a chemist. He is the man who once said - have you heard this quote - "All science is either physics or stamp collecting." And he was talking about the scientific method, I assume.

Robert Lamb: I had not heard that quote.

Allison Loudermilk: So the man in question is Ernest Rutherford, and he was a pretty amazing guy. He was born in New Zealand. He was one of twelve children; that's a large, large New Zealand family, or any family I suppose. He's the guy that came up with - listen to this. He's the guy who came up with the principles of alpha, beta and gamma rays, the proton, the neutron, half life, and daughter atoms.

Robert Lamb: Wow.

Allison Loudermilk: One guy came up with all that.

Robert Lamb: He was on quite a roll.

Allison Loudermilk: Yeah. I've heard him called the father of nuclear physics, and that seems appropriate enough. Future biggies like Niels Bohr, Oppenheimer, and James Chadwick all looked to him for guidance. We're going to talk about one of his adventures with the atomic nucleus and revealing the structure of the atom. So let's talk about what Rutherford was doing.

Robert Lamb: Basically, he was carrying off a kinda simple experiment and one that you can reproduce at home. All need is an alpha ray emitter or some sorta alpha ray gun, you need some gold foil -

Allison Loudermilk: Yeah, and you need a scintillator.

Robert Lamb: What's that?

Allison Loudermilk: A scintillator is essentially, back in the day, it was a screen coated with zinc sulfide. It helps you to figure out where the particles were going after you fired them.

Robert Lamb: Okay. Well, that may be a little hard to get a hold of.

Allison Loudermilk: Perhaps.

Robert Lamb: Still, these are the main elements of the experiment.

Allison Loudermilk: So let's talk about the experiment. It was also called the Geiger-Marsden experiment, named after Hans Geiger, the Geiger counter.

Robert Lamb: A gold foil experiment though sounds a little snazzier.

Allison Loudermilk: Yeah, it does. So here's what they did. They got a source of radioactive particles, like Robert was just alluding to. They fired them through these really thin foils, like, gold. By thin, we mean one or two atoms thick, so super, super, super thin. They encircled their whole setup with the aforementioned detecting screen, the scintillator, the screen that was going to tell them where the particles were going after they fired them.

So what Rutherford and Co. figured out was that most of the radioactive particles were actually firing straight through the foil.

Robert Lamb: Okay, that makes sense.

Allison Loudermilk: Then a few of the particles were being deflected at a smaller angle and, then, a very tiny portion of the particle

s were being reflected back at a large angle.

Robert Lamb: Like we were saying earlier, the deflection tells us that there's something going on inside the material that they're passing through.

Allison Loudermilk: Right. So Rutherford, Geiger and Marsden took that to mean that there was a lot of, quote/unquote, "empty space" in atoms, allowing all those radioactive particles to pass straight through to the particle screen or to the scintillator, but it was the sharp deflections that intrigued them the most.

So their conclusion was that there's a strong positive charge at the heart of the gold atoms that was deflecting those particles almost straight back toward the source. He called this strong positive source that was doing the deflection the nucleus. He said the nucleus must be small compared to the atom's overall size, otherwise you would have had more particles bouncing back, right.

Robert Lamb: Right. So he basically mapped the inside of the atom.

Allison Loudermilk: So today we still visualize the atom as Rutherford did, a small positively charged nucleus surrounded by a vast sparsely populated region with a couple of electrons.

Robert Lamb: Wow, so you can really tell a lot about something by firing some radiation through it.

Allison Loudermilk: It's such a simple experiment, but it's so brilliant.

Robert Lamb: It is brilliant.

Allison Loudermilk: Right. So we mentioned X-ray diffraction a little bit earlier when we were talking about DNA. We were talking about Rosalind Franklin and her X-ray diffraction studies, but as we pointed out, her work owed a lot to Dorothy Crowfoot Hodgkin. She was one of only three women ever to win the Nobel Prize in Chemistry. In 1945, Hodgkin was pretty darned good at X-ray diffraction, so it's not really surprising that she eventually revealed the structure of pretty much one of medicine's most important chemicals.

Robert Lamb: Penicillin.

Allison Loudermilk: Indeed. So back in 1928, Alexander Fleming had discovered the bacteria killing substance, but scientists had a really hard time purifying the chemical in order to develop an effective treatment. So what Hodgkin did was she mapped out the 3-D arrangement of penicillin's atoms and, essentially, she opened all these new avenues for creating and developing semi-synthetic derivatives of penicillin.

Robert Lamb: Yeah, it's like when hackers break the code for something like DVD encryption so that they can rip it. Here was something that was really important to us, penicillin, and, in effect, she allowed us to crack it -

Allison Loudermilk: Right, right.

Robert Lamb: - [inaudible] do more with it.

Allison Loudermilk: Right, by telling us all that stuff about the molecular structure, she helped out a lot. In this case, what she did was, after two different companies sent her penicillin crystals, Hodgkin passed those X ray waves through the crystals and allowed the radiation to strike this photographic plate. We did cover this a little bit before, so as the X rays interacted with the electrons in the sample, they would diffract -

Robert Lamb: - and reveals the inner structure.

Allison Loudermilk: Right.

Robert Lamb: Excellent. Then she went on to deal with other structures, right, like, Vitamin B-12.

Allison Loudermilk: She did, she did.

Robert Lamb: Penicillin was the big one.

Allison Loudermilk: Yeah, penicillin was indeed the big one. Of course, she won the Nobel Prize in Chemistry unshared in 1964, which is a big deal. Usually there are a couple scientists.

Robert Lamb: Kinda selfish.

Allison Loudermilk: Selfish.

Robert Lamb: Yeah.

Allison Loudermilk: I don't know about that.

Robert Lamb: So wow, those are some world changing experiments right there. I feel a little changed just talking about them.

Allison Loudermilk: I feel inspired. I hope there's some world changing experiments going on right now.

Robert Lamb: I'm going to fire some radiation through some stuff just to see what's going on.

Allison Loudermilk: When you get back to your desk?

Robert Lamb: Yeah.

Allison Loudermilk: Yeah, good stuff.

Robert Lamb: What's going on in that cup of coffee.

Allison Loudermilk: Well, the thing is, if you're inspired by our world changing experiments, be sure to listen to Part 2 because we've got more of these coming up.

Robert Lamb: Uh-huh, and there's going to be less radiation passing through things in that one. So if you weren't as into that in this podcast, then there's going to be less next time.

Allison Loudermilk: Yeah. We're going to get into some cool stuff, like, determining the speed of light.

Robert Lamb: Yeah, primordial soup, drooling dogs, all sorts of good stuff.

Allison Loudermilk: Right. So if you want to go to the homepage and look up some cool experiments in the meantime, just type in Science Experiments and you'll get ten science experiments that changed the world.

Robert Lamb: Also, check out our blog where we update you on all sorts of cool things going on involving, say, the world of energy. Hey, Twitter, Facebook, we're on there as well; Lab Stuff on Twitter, Lab Stuff or Stuff From the Science Lab on Facebook.

Allison Loudermilk: If you guys want to talk science, we're there for you.

Robert Lamb: Yes, sign up. Add us, interact with us, that's where we are.

Allison Loudermilk: Or send us an email at Thanks for listening, guys.

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