December 16 – Carb-gone 14

Today’s fasctismal: The oldest age that carbon-14 can give is 114,600 years; the youngest is 570 years.

If you have ever cleaned up a teenager’s room, then you have probably discovered one of the most fundamental tools of archeology: relative dating. (You’ve also discovered what it feels like to excavate a midden pile.) As you dug down through the layers of trash, petrified food, and old homework assignments, you probably noticed that the older stuff was on the bottom and the newer stuff was on the top. But what might surprise you more than the Wall Street Journal hidden under your child’s bed is the fact that until 1949, relative dating was about the only method that archeologists had for dating really old artifacts.

A household in Pompeii (My camera)

A household in Pompeii; we know how old this is thanks to records the Romans kept
(My camera)

That’s because very few artifacts come with a date on them. And even those that do come with an identifying mark, such as coins, only give you an approximate range of dates; for example, a coin with Julius Caesar’s face on it was probably minted sometime between 50 BCE (when he conquered Gaul) and 44 BCE (when his political opponents put a permanent end to his ambitions). And the older something is, the less likely it is to have any sort of identifying mark; an empty, twelve hundred year old clam shell from the Spiro Mound looks an awful lot like an empty, fifteen thousand year old clam shell from Siberia.

This coin provides an approximate date (Image courtesy Australian Centre for Ancient Numismatic Studies)

This coin provides an approximate date
(Image courtesy Australian Centre for Ancient Numismatic Studies)

Archeologists have come up with several methods for working around this problem (e.g., by counting tree rings), but they fail more often than not (after all, how many tree rings are there in a clay pot?). They needed something more. They needed a method that would work on almost everything and that could be easily verified. And, in 1949, a chemist by the name of Willard Libby gave it to them. He realized that by comparing the amount of carbon-14 that was in an object to the amount of carbon-12, he could tell how old something was. But, because carbon-14 had a half-life of 5,730 years, it could only be used to measure things that were between 0.1 and 20 half lives; that is, things that were no younger than 570 years old and no older than 114,600 years old.

But how does carbon dating work? I’ll give you an experiment that you can do at home to understand this basic concept (Teachers: This works really well in a large class if you ad up everyone’s numbers.). To do the experiment, you’ll need 84 pennies, 16 nickles, and 16 dimes. We’ll pretend that the pennies are atoms of carbon-12; because carbon-12 is stable, it doesn’t decay. A carbon-12 atom today will still be a carbon-12 atom 100,000 years from now. And we’ll pretend that the dimes are carbon-14 atoms. Carbon-14 is unstable; in 5,730 years, half of the carbon-14 that is present today will decay into nitrogen-14. (We never run out of carbon-14 because it is always being created by cosmic rays hitting nitrogen-14 in the atmosphere and turning it into carbon-14.)

When a critter dies, the ratio of carbon14 to carbon-12 is fixed

When a critter dies, the ratio of carbon14 to carbon-12 is fixed

Now a living thing will take in carbon-12 and carbon-14, so the proportion of the two atoms will be roughly the same as is in the atmosphere. But once it dies, it stops adding new carbon. As a result, when the carbon-14 decays it changes the ratio of the carbon atoms. To see that, we need to do our experiment. Start by placing the pennies in a pile and lining up the dimes, all heads up. (If you want, you can draw a dead critter around the money.) This is what the ratio of carbon-14 to carbon-12 looked like right after the critter died. There were 84 pennies/carbon-12 atoms and 16 dimes/carbon-14 atoms. (This was a very small critter.)

After one half-life about half of the carbon-14 has turned into nitrogen-14

After one half-life about half of the carbon-14 has turned into nitrogen-14

Since we don’t want to wait 5,730 years for the atoms to decay naturally, we’ll flip the dimes, one by one. If the dime comes up heads, put it back in the critter because it didn’t decay. But if it comes tails, the carbon-14 atom decayed and turned into nitrogen-14 (aka, a nickle). You’ll probably have about eight of the dimes decay, so your new ratio will be 86 pennies/carbon-12 atoms to 8 dimes/carbon-14 atoms. Now flip the dimes again, once more replacing those that come up tails with nickles. Odds are that you’ll lose about 4 dimes this time and your ratio will be 86 pennies/carbon-12 atoms to 4 dimes/carbon-14 atoms. Do it again and you’ll get something close to 86 pennies/carbon-12 atoms to 2 dimes/carbon-14 atoms.

After two half-lives half of the remaining carbon-14 has turned into nitrogen-14

After two half-lives half of the remaining carbon-14 has turned into nitrogen-14

As you can see from the experiment, the ratio can tell you when a critter, such as a possum or a palm tree, died. And if that critter was then used to make something else, such as a shoe or a house, then we know about when the something else was made. So all you have to do to find out how old something is is measure the ratio of the carbon-14 to the carbon-12 in it. Pretty nifty, huh?

After three half-lives half of the remaining carbon-14 has again turned into nitrogen-14

After three half-lives half of the remaining carbon-14 has again turned into nitrogen-14

But I’m willing to bet that your ratios didn’t exactly match mine. That’s because we only used a very few atoms; in most living things, there are quadrillions of carbon atoms instead of just 100. But there are still some variances in the ratios because radioactive decay happens randomly. As a result, most carbon-14 ages have an error of about 3-5% (i.e., a 570-year old sample is probably somewhere between 540 and 600 years old).

So that’s our experiment on carbon dating. And now that you are a fully-qualified archeologist on par with Indiana Jones, why not start doing some real archeology by becoming a Digital Volunteer at the Smithsonian? You’ll look at old documents, type what you see, and help preserve historical records dating back hundreds of years! To learn more, flip over to:
https://transcription.si.edu/

May 30 – Tongue Tied

One of the best things about science is how it corrects mistakes. And one of the worst things about popular culture is how it perpetuates them. Today, Daniel, Peter, and Mary discover the truth behind a popular science myth when they get tongue tied!

 

 

It was a bright, sunny Saturday afternoon and life was just about perfect. Daniel had come to visit Mary and Peter that morning and they’d spent several hours experimenting with kites, trying to discover what sort of tail made a kite fly best. What they had discovered was that the person flying the kite was even more important than the tail. Peter’s kites always flew into trees or crashed into the ground. Mary could keep her kites flying but had a very hard time launching them. But Daniel was a natural kite-flyer and could make even the most unlikely of kites soar high above.

To make the day even better, when they’d gotten back to Mary’s back yard, they found that her father had set up a picnic for them, complete with hot dogs, potato salad, three kinds of pickles, and fresh watermelon. The three friends enthusiastically munched through the piles of food, only slowing down once they reached the slices of watermelon.

“Pass the salt, please,” Mary asked.

“I still don’t get it,” Daniel said as he salted his slice of watermelon and then passed her the condiment. “How can adding salt to watermelon make it taste so good?”

“Dunno,” Peter said. “It just does.”

“Is that any kind of attitude for a scientist to display?” Mary’s father chided gently. “A real scientist would try to figure it out.”

“OK, how do we do that?” Peter replied.

“In science, you always start with what you know. What do we know about taste?”

“Well, last year Mrs. Krabapple had us map our tongues with four tastes,” Mary said. “So we know that there are four different tastes and that they are in different parts of the tongue.”

“As a wise man once said, it isn’t what we know that causes us problem; it is what we think we know that really ain’t so,” her father sighed. “Your teacher was wrong on two counts. First, a taste isn’t found in just one part of your tongue. And second, there are more than four tastes.”

“Huh?” the three young scientists chorused.

“This is sort of like the myth that we only use 10% of our brains when we actually use the whole thing. What happened is that a reporter misheard something and told everyone about it.  The tongue story got started when a psychologist by the name of Boring had translated a German paper that showed different parts of the tongue were more sensitive to different tastes. For some reason, this got reported by the popular press as though those tastes could only be sensed in those parts of the tongue. But you can easily prove that this isn’t true,” Mary’s father said.

“How?” Daniel asked.

“Spoken like a true scientist!” Mary’s father beamed. “First, stick out your tongue and dry it off with a napkin. That will make it certain that the taste doesn’t get spread by the saliva in your mouth. Now take a piece of water melon and touch it to the different parts of your tongue – on the front, on each side, in the middle, and in the back. See how you can taste it all over your tongue?”

The three experimenters followed his directions and quickly discovered that he was right. As they finished their experiment, he continued.

“Now watermelon has a lot of sugar in it, so you were mainly tasting ‘sweet’. We can repeat the experiment with the other tastes if you like, but what it will prove is that you have taste buds for every taste on every part of your tongue. There are actually taste buds on your cheeks and in your throat as well.”

“Wow!” Peter said. “Mrs. Krabapple never said anything about that!”

“She may not have known,” Mary’s father replied. “Sadly, many teachers don’t get the support they need in order to teach science properly.”

“But what about the number of tastes?” Mary demanded. “You said that there aren’t four tastes.”

“That’s right,” her father replied. “Depending on how you want to count them, there may be as few as five or as many as thirteen different distinct tastes. The five tastes that just about everyone agrees on are sweet, sour, bitter, salty, and umami.”

“Ohh-what-si?” Daniel asked.

“‘Ooh-mommy’,” Mary’s father repeated. “It is sometimes called ‘savoriness’ or ‘meatiness’ because it is sort of like the taste of a good steak. Those hot dogs you three scarfed down had a lot of umami.”

“That’s pretty neat, but what do the different tastes have to do with why we like watermelon better with salt on it?” Peter asked.

“Ah, I think I’ll let you figure that out for yourselves. Stay here for a second!”

With that, Mary’s father went back into their kitchen. Mystified, the three young scientists looked at each other. From the kitchen, they heard a variety of cabinets being opened and closed and the clink of plates. After a few minutes, Mary’s father came back out carrying five different plates. As he put the plates on the table in front of them, he explained what the experiment would be.

“In each plate, we’ve got an example of a different taste. The first one has salt for saltiness. The second plate has baking cocoa for bitterness. The third plate has vinegar for sourness. the fourth plate has low-sodium soy sauce for meatiness. And the last plate has sugar for sweetness. And here are a bunch of water crackers; they don’t really have much in the way of flavor,” he paused as Peter grabbed a cracker and tasted it.

“Ugh!” Peter exclaimed. “It tastes like cardboard.”

“Right!” Mary’s father said. “Now here’s the experiment. First, you’ll dip a cracker into each of the different tastes and eat it. That will help you get familiar with the tastes. Then you’ll try dipping the cracker into two different tastes and then eat it. What do you think will happen?”

“Well, the two different tastes will just be two different tastes in our mouths,” Peter said. “Nothing will change.”

“I don’t know,” Daniel said. “Remember what happened when we added salt to the watermelon?”

“That’s right!” Mary exclaimed. “I’ll bet that the tastes change each other somehow.”

“Well, there’s only one way to be sure,” Mary’s father said. “Start tasting!”

What do you think will happen? Try the experiment yourself!

Intro

The three young scientists quickly grabbed crackers and dipped them into each of the plates. From their grimaces, it was clear that they didn’t much care for the tastes by themselves. But something changed when they started dipping the crackers into to tastes before eating them.

“Hey!” Peter excitedly said. “Did you guys try this? Sweet plus bitter – it tastes almost like a candy bar!”

“Cool!” Daniel replied. “I like sour and salty – it tastes like a pickle!”

“And salty plus umami is wonderful!” Mary added. “This is so delicious!”

“Can you figure out why it is so good,” Mary’s father asked. “You’ve definitely got enough information to form a hypothesis now.”

“Well, one taste by itself isn’t very good,” Peter said. “And it only hits one set of taste buds.”

“But two different tastes together are good, ” Mary said.

“And they hit two different sets of taste buds,” Daniel added. “So maybe the more different taste buds that get excited, the better the food tastes?”

“That’s right!” Mary’s father said. “That’s why the best recipes always have several different tastes in them. Cookies always have sweet and salty. Soda usually has sweet and sour. Soup has umami and salty. And so forth. Companies spend billions of dollars trying to find the perfect combination of different flavors. For example, what do you think would happen if you used umami with your watermelon instead of salty? Or if you used bitter?”

“I don’t know,” Peter started.

“But we sure want to find out!” Daniel and Mary chorused together. Smiling, the three scientists grabbed watermelon slices and began their most edible experiment of the day.

September 28 – Oh, Baby!

Today’s Factismal: When a baby smiles with its teeth apart and showing, the baby is frightened. When a baby smiles with its teeth hidden, the baby is happy.

The human smile is a puzzling thing. We know that we do it when we are happy, but why do we do it? And why do we smile with our teeth together when most other primates smile with them apart? And when does this behavior start? Is it programmed into us by society or is it more intrinsic?

These monkeys aren't mad - they are playing (Image courtesy Psychology Today)

These monkeys aren’t mad – they are playing!
(Image courtesy Psychology Today)

It turns out that when a typical primate smiles with its teeth apart and gums pulled up to show off the teeth, it is usually (but not always) showing aggression. And when it smiles with its teeth together or the lips down to hide the teeth, it is showing submission. The only exception to this behavior appears to be what primatologists call “rapid facial mimicry” and what parents call “making faces”. Two or more primates will grimace at each other, trying to match the other’s face, as a way of becoming better friends. (No word on if their faces ever freeze that way.)

This baby is having a good time - or is he? (Image courtesy Baby Laughter Project)

This baby is having a good time – or is he?
(Image courtesy Baby Laughter Project)

Being primates ourselves, humans exhibit many of the same behaviors. But society always adds a veneer of confusion onto the basic data, which is why scientists who study the evolution of human behavior like to watch babies – they haven’t been as influenced by social norms and show a purer response. And they’ve found that human babies tend to follow the primate rule: teeth together and gums hidden, happy baby; teeth apart and gums showing, unhappy baby. And it isn’t just babies that follow these rules; the same pattern has been observed in blind people who have never had an opportunity to see others smile.

Of course, babies do more than smile; they also laugh. And that’s another rich field for research (and a little squee). If you happen to be the parent of a young baby, then the folks at the Baby Laughter Project would like your help in finding out why babies laugh and what that tells us about how our brains develop. If you’d like to help (or just want to watch videos of laughing babies), then head over to
http://babylaughter.net/

September 15 – Making the Tardigrade

Today’s factismal: The water bear has inspired a new type of glass.

If you have a crazy uncle (and who doesn’t?), odds are you’ve heard him say something like “Why do we spend so darn much on science? It never does nothing for us nohow!” Fortunately, it isn’t very hard to show your uncle where he’s wrong. For example, researchers have found new antibiotics from bacteria living in mud, have reduced the death rate to all-time lows using vaccines, turned fatal diseases into manageable problems, and found ways to speed shipping. And most recently, they have found a way to turn a tardigrade’s protective system into a stronger and clearer form of glass.

A tardigrade on a Q-tip (Image courtesy Darron Birgenheier)

A tardigrade on a Q-tip
(Image courtesy Darron Birgenheier)

What is a tradigrade, you ask? Why just one of the most amazing critters on Earth (or off of it). These little “water bears” shuffle about on moss, sucking the sap and being generally awesome. Also known as moss piglets, they have eight legs, a sharp snout, and an amazing ability to adapt. They are found in the depths of the ocean, on the highest mountains, in hot springs at 150°F, and below freezing ice. They can even go into a type of suspended animation when things get too extreme and come back to life when things get better later on.

A tardigrade getting along swimmingly (Image courtesy Tommy from Arad)

A tardigrade getting along swimmingly
(Image courtesy Tommy from Arad)

And that last trick was the clue that led to a new form of glass. When tardigrades go into suspended animation, they shed almost all of their water which mixes with proteins and other things on their outer shell and turns into a glasslike molecule that shields them from the environment. When researchers saw that, they decided to see if they could replicate the trick using ordinary glass. By depositing one thin layer of molecules at a time, they were able to build a glass that has a regular structure and some pretty irregular (for glass) properties. It was able to transmit light more efficiently, making it ideal for lasers and leds and solar cells. And it was stronger, making it ideal for screens and surgical tools. And all of this came about because some scientists looked at a tardigrade and asked “why can’t we do that?”

So the next time someone asks you what use science is, point to the handy tardigrade (assuming you can find one) and say “ask it!”

June 27 – Silver Lining

Scientists do their best work when faced with contradictory results. If you always get just one result, then what you are investigating isn’t very interesting. But if sometimes you see one thing and sometimes you see another, then that’s Nature’s way of telling you that you are on the verge of learning something truly neat. And that’s what happens to Mary, Peter, and Daniel today as they look for the silver lining.

The atmosphere in Peter’s living room was just perfect for the Secret Science Society’s annual “Mad Science Movie Marathon”. While Mary, Peter, and Daniel indulged in huge bowls of popcorn, plates of caramel apples, and glasses of swamp juice (lemon soda with food coloring and raisins), classic monster movies from the 1950s ran on the DVD player and a fierce storm raged outside. They had laughed at The Mummy’s bad hieroglyphics, howled along with The Wolfman, and shivered as Frankenstein brought his creation to life with the lightning on the screen being echoed by real thunder from the storm outside. Naturally, just as the villagers gathered up their pitchforks to explain the homeowner association rules to poor, mad Victor, a bright flash of light and an ear-shattering crack told of a near-miss and the television and lights and all other power went off in the house.

“Don’t worry,” Peter said. “I know where the emergency flashlights are.”

“Rats!” said Daniel. “It was just getting good!”

“I wonder how long it will take to get the power back,” Mary mused. “And what will we do while we wait?”

“I’ve got a better question,” Daniel said. “Why is it dark?”

“Huh?” said Peter as he came back into the room with three flashlights.

“Think about it,” Daniel said. “When you look at a cloud on a sunny day, the cloud is white. Sometimes it even seems brighter than the sky around it. So why is it dark under a rain cloud? Aren’t they all the same thing?”

“I hadn’t thought about it,” Mary replied. “But you are right. Rain clouds are dark but regular clouds aren’t. I wonder why?”

“Well, it is too wet outside to go ask Mr. Medes,” Peter said. “Do you think my mom might know?”

“Might know what?” Peter’s mother asked as she came into the room with more flashlights. “I thought you might need these but I see you’ve got things well in hand!”

“Daniel asked something that we don’t know the answer to,” Mary said. “Why is it dark when it rains if clouds are white?”

“Well, there’s no shame in not knowing something. The only shame is if you don’t try to find out what the answer is,” Peter’s mother replied. “And it turns out that the answer to your question happens to apply to my work. So, yes, I know the answer.”

“What is it?” Daniel asked.

“Well, would you rather I told you or would you prefer to do an experiment?”

“Experiment! Experiment!” the three young scientists chorused.

“OK. Peter, go get that bag of marbles from your room,” his mother directed. “And I’ll go get some clear plastic bags from the kitchen. We’ve already got flashlights, so we’re all set.”

Peter quickly went to his bedroom and grabbed the bag of marbles. As he came back into the den, his mother returned with four plastic bags. Taking the marbles from Peter, she filled each bag with marbles before sealing it and handing it to one of the scientists.

“OK,” she said as she filled her bag with marbles. “This would work better if the marbles were clear instead of having that swirl of color in the middle, but it is close enough for our purposes. What I want you to do is shine your flashlight through the bag of marbles cross-wise so that the light goes through the ‘thin way’. What happens?’

“I can see the light but it is a bit fuzzy,” said Daniel.

“And the edge of some of the marbles gets bright,” added Mary.

“Good,” said Peter’s mother. “Now, what I want you to do is shine the light through the bag of marbles the long way. But, before you do, tell me – what will you see?”

“Probably the same thing we just saw,” said Peter. “The light will be fuzzy and there will be some bright edges.”

“I don’t know,” said Daniel. “Maybe having more marbles means that the light won’t make it through somehow.”

“Or maybe we’ll just see bright edges,” added Mary.

“Well, there’s only one way to find out!” Peter’s mother said.

What do you think will happen? Try the experiment yourself!

The three turned their baggies longwise and looked at the flashlight shining through. But instead of a bright light, they only saw a dull, fuzzy beam. The marbles had dimmed the flashlight beam just as clouds dulled sunbeams.

“Wow!” exclaimed Peter. “The light got a lot darker.”

“And most of the bright edges are gone!” said Mary.

“But why?” asked Daniel.

“The reason for this is the same reason that the bottom of the ocean is dark and that radio waves don’t travel very far in a nebula,” Peter’s mother said. “It is a type of physics known as optics. When the light from the sun or from a flashlight beam hits an object, three things happen: reflection, refraction, and absorption.”

“Reflection like a mirror?” Mary asked.

“Exactly! You may have noticed that you can see your face in a very still pond; that’s because some of the light that hit the top of the water was reflected back at you,” Peter’s mother explained. “The same thing happens with our marbles and with the raindrops that make up a cloud. Some of the light gets reflected back off of every raindrop. As you get deeper into the cloud or the cloud gets thicker, less and less light makes it through.”

“Oh, so that’s why rainclouds clouds are dark! They are thicker than other clouds!” Peter said.

“No, that’s only part of the explanation,” his mother replied. “There’s also refraction; that’s what happens when the light gets bent by the raindrop. Instead of traveling through and continuing in a straight line like a toothpick in an olive, the raindrop makes the path of the light shift a little so it looks more like a broken toothpick in an olive. And because the angle of the break is different for each color of light, when the angle is just right, you can get -”

“A rainbow!” Daniel said. “Is the bent light what made the edges of the marbles seem bright?”

“That’s exactly right,” Peter’s mother said. “Taken together, we sometimes refer to reflection and refraction as scattering. But reflection and refraction are only part of the reason that rain clouds are dark. The third reason is – ”

“Absorption!” Mary said. “Is that like when a sponge absorbs water?”

“Not quite,” Peter’s mother said. “With a sponge, you can always get the water back out by squeezing it. But when light gets absorbed by a raindrop, it gets changed into heat. That added energy might make the raindrop warm up a very little bit or it might be re-radiated as infrared light. And since we can’t see in infrared, that makes it dark in the center of a rain cloud and under one, too.”

“But what does that have to do with the ocean bottom?” Peter asked.

“You can think of the ocean as a whole bunch of raindrops jammed together,” his mother replied. “As the light goes through the ocean, some of it gets absorbed. Interestingly, the depth that the light makes it down to depends on the wavelength of the light. Colors like red have very long wavelengths and make it deeper into the ocean than colors like blue. In addition, water like to scatter the shorter wavelength colors like blue; that’s why the ocean looks blue – more of that color gets reflected to your eyes. Taken all together, the amount of light that you can see in the ocean drops by 90% for every 75 meters. So if the ocean was as deep as a skyscraper is high, the bottom floor would get only 10% as much light as the top one would.”

“Cool!” Daniel said. “But what does that have to do with your work?”

“I’m a planetologist,” she replied. “That means that sometimes I look at planets before they are born, when they are just big clouds of gas and dust called nebulae. The gas and dust in a nebula will scatter and absorb light just like the water in the ocean or the raindrops in a cloud. And by measuring how the light from stars behind the nebula is scattered and absorbed, we can estimate the thickness of the cloud and even learn what it is made of. We’ve found water, ammonia, formaldehyde, and even amino acids in nebulae across the galaxy. There are even some scientists who think that life on Earth started thanks to those amino acids.”

“Neat!”

Just then, the power came back on.

“Well, it looks as if your creation has come back to life,” Peter’s mother said. “So I’ll just leave you three to your movies.”

“Thanks mom!” Peter said, his fingers already on the remote, ready to start the movie again as the three sat back down absorbed once more in the morality tale on the silver screen.

June 20 – Tongue Tied

One of the best things about science is how it corrects mistakes. And one of the worst things about popular culture is how it perpetuates them. Today, Daniel, Peter, and Mary discover the truth behind a popular science myth when they get tongue tied!

 

 

It was a bright, sunny Saturday afternoon and life was just about perfect. Daniel had come to visit Mary and Peter that morning and they’d spent several hours experimenting with kites, trying to discover what sort of tail made a kite fly best. What they had discovered was that the person flying the kite was even more important than the tail. Peter’s kites always flew into trees or crashed into the ground. Mary could keep her kites flying but had a very hard time launching them. But Daniel was a natural kite-flyer and could make even the most unlikely of kites soar high above.

To make the day even better, when they’d gotten back to Mary’s back yard, they found that her father had set up a picnic for them, complete with hot dogs, potato salad, three kinds of pickles, and fresh watermelon. The three friends enthusiastically munched through the piles of food, only slowing down once they reached the slices of watermelon.

“Pass the salt, please,” Mary asked.

“I still don’t get it,” Daniel said as he salted his slice of watermelon and then passed her the condiment. “How can adding salt to watermelon make it taste so good?”

“Dunno,” Peter said. “It just does.”

“Is that any kind of attitude for a scientist to display?” Mary’s father chided gently. “A real scientist would try to figure it out.”

“OK, how do we do that?” Peter replied.

“In science, you always start with what you know. What do we know about taste?”

“Well, last year Mrs. Krabapple had us map our tongues with four tastes,” Mary said. “So we know that there are four different tastes and that they are in different parts of the tongue.”

“As a wise man once said, it isn’t what we know that causes us problem; it is what we think we know that really ain’t so,” her father said. “Your teacher was wrong on two counts. First, a taste isn’t found in just one part of your tongue. And second, there are more than four tastes.”

“Huh?” the three young scientists chorused.

“This is sort of like the myth of Brontosaurus which was really an Apatosaurus and the myth that we only use 10% of our brains when we actually use the whole thing. What happened is that a reporter misheard something and told everyone about it. What happened is that a psychologist by the name of Boring had translated a German paper that showed different parts of the tongue were more sensitive to different tastes. For some reason, this got reported by the popular press as though those tastes could only be sensed in those parts of the tongue. But you can easily prove that this isn’t true,” Mary’s father said.

“How?” Daniel asked.

“Spoken like a true scientist!” Mary’s father beamed. “First, stick out your tongue and dry it off with a napkin. That will make it certain that the taste doesn’t get spread by the saliva in your mouth. Now take a piece of water melon and touch it to the different parts of your tongue – on the front, on each side, in the middle, and in the back. See how you can taste it all over your tongue?”

The three experimenters followed his directions and quickly discovered that he was right. As they finished their experiment, he continued.

“Now watermelon has a lot of sugar in it, so you were mainly tasting ‘sweet’. We can repeat the experiment with the other tastes if you like, but what it will prove is that you have taste buds for every taste on every part of your tongue. There are actually taste buds on your cheeks and in your throat as well.”

“Wow!” Peter said. “Mrs. Krabapple never said anything about that!”

“She may not have known,” Mary’s father replied. “Sadly, many teachers don’t get the support they need in order to teach science properly.”

“But what about the number of tastes?” Mary demanded. “You said that there aren’t four tastes.”

“That’s right,” her father replied. “Depending on how you want to count them, there may be as few as five or as many as thirteen different distinct tastes. The five tastes that just about everyone agrees on are sweet, sour, bitter, salty, and umami.”

“Ohh-what-si?” Daniel asked.

“Umami,” Mary’s father repeated. “It is sometimes called ‘savoriness’ or ‘meatiness’ because it is sort of like the taste of a good steak. Those hot dogs you three scarfed down had a lot of umami.”

“That’s pretty neat, but what do the different tastes have to do with why we like watermelon better with salt on it?” Peter asked.

“Ah, I think I’ll let you figure that out for yourselves. Stay here for a second!”

With that, Mary’s father went back into their kitchen. Mystified, the three young scientists looked at each other. From the kitchen, they heard a variety of cabinets being opened and closed and the clink of plates. After a few minutes, Mary’s father came back out carrying five different plates. As he put the plates on the table in front of them, he explained what the experiment would be.

“In each plate, we’ve got an example of a different taste. The first one has salt for saltiness. The second plate has baking cocoa for bitterness. The third plate has vinegar for sourness. the fourth plate has low-sodium soy sauce for meatiness. And the last plate has sugar for sweetness. And here are a bunch of water crackers; they don’t really have much in the way of flavor,” he paused as Peter grabbed a cracker and tasted it.

“Ugh!” Peter exclaimed. “It tastes like cardboard.”

“Right!” Mary’s father said. “Now here’s the experiment. First, you’ll dip a cracker into each of the different tastes and eat it. That will help you get familiar with the tastes. Then you’ll try dipping the cracker into two different tastes and then eat it. What do you think will happen?”

“Well, the two different tastes will just be two different tastes in our mouths,” Peter said. “Nothing will change.”

“I don’t know,” Daniel said. “Remember what happened when we added salt to the watermelon?”

“That’s right!” Mary exclaimed. “I’ll bet that the tastes change each other somehow.”

“Well, there’s only one way to be sure,” Mary’s father said. “Start tasting!”

What do you think will happen? Try the experiment yourself!

 

 

 

 

 

The three young scientists quickly grabbed crackers and dipped them into each of the plates. From their grimaces, it was clear that they didn’t much care for the tastes by themselves. But something changed when they started dipping the crackers into to tastes before eating them.

“Hey!” Peter excitedly said. “Did you guys try this? Sweet plus bitter – it tastes almost like a candy bar!”

“Cool!” Daniel replied. “I like sour and salty – it tastes like a pickle!”

“And salty plus umami is wonderful!” Mary added. “This is so delicious!”

“Can you figure out why it is so good,” Mary’s father asked. “You’ve definitely got enough information to form a hypothesis now.”

“Well, one taste by itself isn’t very good,” Peter said. “And it only hits one set of taste buds.”

“But two different tastes together are good, ” Mary said.

“And they hit two different sets of taste buds,” Daniel added. “So maybe the more different taste buds that get excited, the better the food tastes?”

“That’s right!” Mary’s father said. “That’s why the best recipes always have several different tastes in them. Cookies always have sweet and salty. Soda usually has sweet and sour. Soup has umami and salty. And so forth. Companies spend billions of dollars trying to find the perfect combination of different flavors. For example, what do you think would happen if you used umami with your watermelon instead of salty? Or if you used bitter?”

“I don’t know,” Peter started.

“But we sure want to find out!” Daniel and Mary chorused together. Smiling, the three scientists grabbed watermelon slices and began their most edible experiment of the day.

June 13 – Round And Round

One of the best things about science is how an observation in one area can apply to something in a completely different area. Our friends Peter and Mary will discover that and much more in today’s episode of the Secret Science Society!

If you have a friend, then you know that the only thing more fun than having your friend come to your birthday party is getting to go to his. And the only thing more fun than that is getting to play with the goodies that you got at the party. And both Peter and Mary had been lucky at their friend Daniel’s party. Mary had won a toy car when they played charades and Peter was coming home with a helium balloon he won during the trivia contest. As they watched for their ride home, they played with their new prizes.

“Hey! There’s my mom!” Peter said.

“Thanks again for a great party, Daniel!” Mary said. Her father had brought the two of them to the party and she was going to ride back home with Peter; living next door had some advantages.

“Glad you could come,” Daniel said. As the new kid at school, he didn’t have many friends yet, but sharing experiments with Peter and Mary had already turned them into a close-knit group. “And thank you for the lab coat! I can’t wait to try it out! And the air cannon is great – I couldn’t believe it when it blew out my candles!”

“Glad you like it,” Peter and Mary chorused as they headed out the door and clambered into the car.

“Are you both buckled in?” Peter’s mother asked.

“Yes!” the two said, and the car pulled out. Mary put her toy car on the seat between her and Peter, and Peter let his balloon float in the air above his knees. As the car stopped at a stop sign, Mary suddenly grabbed for the toy car.

“Hey!” Mary exclaimed. “The car’s trying to escape!”

“Well, that beats being hit in the face by a balloon!” Peter replied. As the car sped away from the stop sign, Mary’s toy car rolled back and Peter’s balloon swung toward the front of the car.

“That’s weird,” he said. “My balloon goes the opposite direction of your car. I wonder why?”

“If you’ll wait until we get home,” Peter’s mother said, “I can show you. Even better, we can do an experiment to find out the answer.”

Since experiments were one of Mary and Peter’s favorite things to do, they cheerfully agreed. Almost as soon as the car stopped in Peter’s driveway, the two young scientists hopped out and looked expectantly at Peter’s mother.

“OK,” she laughed. “Let’s go do some science!”

Taking them into the kitchen, she gave each of them a raw egg.

“What does this have to do with balloons and toy cars?” Mary asked.

“You’ll see,” Peter’s mother replied. “What I want you to do is spin the egg as quickly as you can. Once it is spinning, put your hand on the egg for a second to stop the spinning and then take your hand off. What will happen?”

“The egg will just sit there,” Mary said.

“I don’t know,” Peter said. “It might act like the car somehow.”

“Well, there’s only one way to find out,” Peter’s mother said. “On the count of three, spin!”

What do you think will happen? Do the experiment!

 

 

 

 

 

“One, two three!”

Peter and Mary quickly spun their eggs. As soon as the eggs started to spin around, they put a hand on them and stopped the egg. Then they took their hands away and watched in amazement as the eggs started to spin again!

“Hey! What gives?” Mary asked.

“That egg is a lot like the inside of the car,” Peter’s mother replied. “Just as the car is a hard shell of steel filled with air, an egg is a hard shell of calcium carbonate filled with liquid. And both air and egg white and every other physical thing in the universe have something in common – they all have mass.”

“But that just makes things weigh a lot and keeps stuff on planets,” Peter objected. “It can’t make something spin after you stop it!”

“Actually it can,” his mother said. “You’re right that mass is what gives things weight. But mass also has another feature; it creates inertia – the tendency for something to keep moving in the direction it is going. When you spun the egg, you started the liquid inside spinning. And though you stopped the outside of the egg, you weren’t able to stop the liquid inside thanks to its inertia. So when you took your hand off of the egg, the liquid made it start spinning again.”

“But what if I used a hard boiled egg?” Mary asked.

“Then everything would be stuck together and the egg wouldn’t start spinning again; that’s one way to tell if you have a hard-boiled egg or a raw one,” Peter’s mother replied. “But the same thing happens in a car that happens in that egg. When the car started moving, inertia kept the stuff inside of it from going with it right away.”

“Is that why you get pushed back in the seat when my dad drives?” Mary asked.

“Yes; it takes a little time for the car’s cushions to give your body the same speed as the rest of the car and that’s what pushed you back. And that’s why your toy car rolled back when the car started moving forward – it didn’t have the same speed as the car and tried to stay in place. And when the car stopped, your toy car rolled forward; if you hadn’t caught it, then it would have had an accident.”

“So that’s why we wear seat belts!” Peter said. “They help hold you in place and keep you from moving forward when the car gets in an accident and stops suddenly.”

“Right,” his mother said. “So can you figure out why the balloon went the opposite way to the toy car?”

“The balloon must have been pushed by something, or its inertia would have kept it right above my knees,” Peter said.

“The air!” Mary exclaimed. “Your balloon is lighter than air! When the car starts up, the air gets pushed back by its inertia. Because the balloon is lighter than air, it gets pushed forward when the air moves back!”

“That’s exactly right! Well done!” Peter’s mother looked at the clock. “But it is getting late and Peter has enough inertia in the morning already – he doesn’t need any more!”

“OK! Thanks for the ride back home,” Mary said . “And thanks for the experiment!”

Smiling, she headed out the door and over to her house as her brain filled with ideas for using inertia.