The study of matter is one of the most basic sciences. If you dig deep enough, most areas of science are built on a foundation of understanding matter.

Overview

What is Matter?

Before we can dive into the study of matter, we really should know what matter is. Luckily, the definition is short, and fairly easy.

• What is the difference between mass and weight?

States of Matter

What is matter?

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If you have read many of these experiments, you know that I like experiments that deal with food. Part of this is because I really like to eat. I also like to cook, finding it very relaxing. I also seem to get lots of good feedback from the food related experiments, telling me that many of you like to eat too. This experiment comes from the wonderful dinner we had tonight. Our good friends Bob and James came by today and we went out to eat. I ordered a bucket of steamed oysters (I LOVE oysters!) and I was enjoying dipping them in the various combinations of horseradish, cocktail sauce, and butter. I especially like the clarified butter you get with seafood and that got me thinking about the chemistry butter. To investigate this, you will need:

• at least a couple of tablespoons of butter (not margarine)
• a skillet or sauce pan

Lets start with the history of butter. Butter has been used for a long time. There are references to butter as far back as 2000 BC, although at that time it was used mostly as a medicinal ointment and as oil for lamps. Today, most butter is made from cow's milk, but it has also been made from the milk of goats, sheep, horses and other mammals. There are different ways to make butter, but basically you let whole milk separate so that the cream comes to the top. This cream is then churned or shaken, causing the bits of butterfat in the milk to stick together, forming lumps of butter.

If you want to try that yourself, check out the Making Butter video.

Butter is actually several different substances mixed together. We are going to separate these substances. Cut a couple of tablespoons of butter into small pieces and put them in the pan. Turn the heat on low and watch as the butter melts. You will quickly notice that there are different parts to the butter.

Clear butter fat and white milk proteins

You will see a clear, yellow liquid with lots of white bits floating in it. Continue heating and you will notice that the butter begins to sizzle. At this point, remove it from the heat.

There will be a white foam floating on top of the butter and bits of white, solid stuff will settle to the bottom. In the middle is the yellow liquid. Use a spoon to remove the white foam. You can then carefully pour the yellow liquid into a small container.

boiling the water

Another way to make clarified butter is to place the butter in a small container and place it in a very warm place. The butter will melt and separate into layers. You can then spoon off the foam from the top and carefully pour off the clear, yellow liquid. You don't get the sizzle, so you miss seeing evidence of one of the substances present in the butter, but you also don't need to use the stove.

OK, now what is all this stuff? Well, butter is made up of fat, protein, and water. They form an emulsion, which means that you have a mixture of substances that usually don't mix (oil and water).

Some of the proteins brown,
giving the butter fat a wonderful flavor.

Often, butter has salt and air added to it as well. As you melted the butter, the emulsion separates. The yellow liquid is the fat. The solid, white stuff is the milk proteins. The sizzle of the heated butter was the water boiling away. The foam which forms on top of the butter is mostly due to air that is trapped in the butter during processing.

You can use either salted or unsalted butter in this experiment. If you use salted butter, you need to watch it more closely to keep it from scorching. The salt raises the boiling point of the water in the butter, which means less time between when the water starts to boil and when the proteins begin to burn.

Why do people make clarified butter, which is also known as drawn butter? There are several reasons. First, by removing the solid milk proteins, you can use the butter to cook at much higher temperatures. Regular butter begins to smoke when you heat it to about 248 degrees Fahrenheit. At that point, the proteins begin to scorch, producing a bitter flavor. By removing these proteins, you can heat the clarified butter up to 375 degrees before it starts to smoke. This makes it very useful for cooking food which you want to cook at a high temperature.

The second reason for removing the milk proteins is that it helps keep the butter from spoiling. These proteins are largely responsible for the butter going rancid as it gets old, and properly clarified butter can be kept for a long time without going bad. The better job you do of removing these proteins, the longer the butter will keep.

Now, I can hear some of you asking why isn't all butter clarified. Removing the milk proteins also removes a lot of the flavor. Once it cools, compare the taste of the clarified butter with regular butter and you should taste a big difference. While it tastes marvelous with oysters, lobster and other seafood, it would not have the butter flavor that we like in other foods. Don't waste that clarified butter! If you don't have any oysters or lobster laying around, it is also very good on popcorn. Or heat it again with some garlic, and use it for dipping crispy strips of toasted bread. YUM!

A classic investigation into the chemistry of bones.

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With the holidays upon us, I am once again reading through Michael Faraday's Chemical History of a Candle. You can find it online at http://www.gutenberg.org/etext/14474. Truly a wonderful book. I was trying to think of a new candle experiment and came across a package of the "magic relighting candles" in the birthday card section at the grocery store. These are the ones that relight themselves a few seconds after you blow them out. How do they work? Let's find out. You will need:

• a candle
• a lighter
• one of the self relighting candles

First, lets burn the regular candle. Place it in a secure holder, so it does not fall over. Light the candle and let it burn for a couple of minutes. Check to see that it has formed a nice pool of melted wax around the base of the wick. Then blow out the candle. You should see a column of white smoke rising from the wick. Blow strongly on the wick, and you should see an ember glowing at the end of the wick. That ember and the white smoke are two of the important parts of the relighting candle.

The white smoke is really vaporized paraffin, the stuff the candle is made from. The glowing ember is hot enough to continue vaporizing the paraffin, but not hot enough to set the vapor on fire to relight the candle. That calls for a third ingredient.

Place the relighting candle in a holder. I have found that a cupcake or brownie works very well for this. I also put a little ice cream around it, just for safety. Light the "magic" candle, and let it burn for a few seconds. Then pretend it is your birthday, and blow out the candle. Watch the candle carefully. You should see the same rising column of white smoke. You will probably also see the glowing ember, but do not blow on the wick this time. Instead, watch closely. After a few seconds, the candle relights itself. Just as it relights, you should see something else. There should be tiny, bright sparks that jump from the wick. That is the third thing that we need to have a relighting candle, but what makes the sparks?

The sparks are caused by tiny bits of the metal magnesium. Magnesium is a very light metal. It also burns with a very hot flame. Tiny bits of magnesium are mixed into the wick. While the candle is burning, liquid wax flowing up through the wick keeps the magnesium cool enough not to burn, but once the candle is blown out, the wax cools and stops rising. That lets the glowing ember heat the magnesium bits enough to set some on fire. They burn hot enough to set the paraffin vapor on fire, relighting the candle.

If you relight the candle several times, you will probably get some nice bursts of sparks. Repeated melting can cause some of the particles to concentrate in one place. When they get hot enough, you get a nice, miniature fireworks display.

Once you are done, but sure that the "magic" candle is out. Put it in some water for a little while to be sure. It would not be a good thing to put it into the garbage, and then have it relight again.

Be sure to dispose of the cupcake or brownie properly too, preferably with a little hot fudge sauce and a fork.

To go into this subject deeper, try the following:

The Fire Diamond: To understand what we need to have a fire.

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Several people have written me lately, asking how to make simulated geodes in egg shells. Geodes are pockets of crystals that form in sedimentary and igneous rocks. They start as hollow spaces in rock that is porous enough for water to seep through. The water carries dissolved minerals, which are deposited in the open space, forming a lining of crystals. Most geodes contain quartz crystals, but they can also contain calcite, celestite, and other minerals.

Many rock shops and museum gift shops sell geodes that have been cut, and sometimes dyed to make them more colorful. Sometimes you can buy unbroken geodes, which lets you break them open yourself. That is particularly fun, as you never know how it will look until you open it.

If you don't have a place to collect geodes, you can make quick, easy, simulated geodes by using egg shells for the hollow spaces. I have seen several different recipes, many of which take days, but you can make an egg shell geode in a few hours by using epsom salts for the crystals. We will be using basically the same formula that we used for Growing Crystals from Solution, so you will need:

• several egg shells, washed and cleaned
• an egg carton to hold the shells
• epsom salts, available at pharmacies and grocery stores
• hot water
• a measuring cup
• a refrigerator
• food coloring

Start by making an omelet or something else yummy that requires eggs. For the best results, crack the eggs close to the small end of the egg. This leaves you a fairly large egg shell to use. The larger the egg shell, the more crystals you will have. Wash the shell, and remove the skin-like membrane that lines the shell. For short term projects, you can leave this membrane in place, but you should remove it if you plan to keep your geode for a long time, as the membrane tends to mold after a while.

Depending on how many eggs you are going to use, you may not need as much of the solution as we used before. I tried using 1/4 cup of epson salts and 1/4 cup of hot water, and it worked fairly well for 6 egg shells. You want the water to be hot, but not boiling. Stir in the epsom salts. If it all dissolves, add another spoon full. Place the egg shells in the egg carton, so they won't tip over and make a mess. Then pour the epson salt solution into the shells.

If you want brightly colored crystals, add a drop of food coloring. You might even try adding small drops of two or more colors to the same shell. Be sure to leave some of them uncolored, because I think the pure crystals are prettier than the colored ones.

Carefully place the egg carton into the refrigerator. Put it in a place where it will not be bumped or disturbed, and let it sit for at least 3 hours. That will give your crystals plenty of time to form.

Once you have plenty of crystals, remove the egg carton from the refrigerator. There will still be liquid in the shells, which you can carefully pour into the sink. Be careful not to let the crystals fall out of the shell as you drain them. Each shell should have a mass of needle-shaped crystals inside. As they dry, they will become even more bright and shiny.

You can play with the concentration of the epson salts. Adding more epson salts to the water will give you a denser cluster of crystals, while adding a bit less will give you a better view of the individual crystals. If you used clean egg shells, your crystals should remain bright and shiny for weeks.

Link to Penny Chemistry, part 1

Last time, we used a mixture of salt and vinegar to remove the tarnish from pennies. This time, we will get back some of the dissolved copper by collecting it on some iron nails. To try this you will need:

• a small glass, cup, or bowl
• vinegar
• salt
• several pennies
• several iron nails

The start of this experiment is pretty much a repeat of part of last week's experiment. Put a couple of inches of vinegar into a cup. Add a teaspoon of salt, and give it a stir to help it dissolve. This time, instead of dipping a penny halfway into the solution, drop in several pennies.

Very quickly, you will see the same thing happen that we saw last time. The pennies will lose their coating of oxides, becoming bright and shiny. In the process, some of the copper is being dissolved in the vinegar/salt solution.

To get some of that copper back, drop a couple of iron nails into the solution. After a minute or so, you will see tiny bubbles forming on the nails. After an hour or so, look at the nails again. They should have a thin coating of copper.

Why does the copper coat the nails? The solution that dissolved the copper from the pennies is also dissolving some of the iron from the nails. As the atoms of iron dissolve, they leave behind electrons, giving the nail a negative electric charge. Both the iron and copper atoms dissolved in the solution have a positive charge, but the copper is more strongly attracted to the nail, so the copper atoms stick to it, forming a coating.

The bubbles are hydrogen gas, produced by a reaction between the hydrogen ions from the vinegar and the metals. Once enough copper atoms have been deposited to balance out the negative charge on the nail, the process stops.

Does it make a difference if the nail is touching the penny? Try suspending the nail by a string, so it does not touch the copper. Does it still work? To see a stronger contrast, try suspending the nail so that only half is in the vinegar. That part should get a copper coating, while the part above the liquid should remain as it is.

Way back in the 70's, when I was working at the Memphis Pink Palace Museum, part of our Kitchen Chemistry program involved using packets of ketchup to remove the tarnish from pennies. You take a dull, brown, tarnished penny and rub it with some ketchup. In seconds, the penny is bright and shiny. Usually, the experiment stops there, but I thought we might take a look to see why it works. To try this, you will need:

• ketchup
• water
• vinegar
• salt
• potassium chloride (salt substitute)
• 5 small cups or bowls
• 6 or more tarnished pennies
• labels and a marker

Safety Warning

Before you go wild with pouring different chemicals together, remember to keep safety in mind. For the stuff in your refrigerator and spice cabinet, you can pretty much mix whatever you want. Tuna fish and grape jelly may not be tasty, but it will not explode or burn off your fingers. Outside your refrigerator, you need to be much more careful. Cleaning supplies and other household chemicals can be harmful by themselves, and if the wrong ones are mixed they can be deadly. Only use them for experiments that specifically call for them.

Experiment

A good place to start is with the original experiment. Put a little ketchup onto one of the tarnished pennies. Let is sit there for about 30 seconds, and then rinse it. What you should find is that the tarnish has been removed from the part of the penny that was in the ketchup. OK, so that works just as well as it did back in the 70's.

Next, take a look at the ingredients for the ketchup. Besides tomatoes, you will notice that two prominent chemicals are vinegar and salt. A little internet research will show you many other science experiments that use vinegar and salt for doing the same thing as the ketchup. If you want to be sure that the tomatoes are not responsible for cleaning the pennies, try using some tomato sauce that does not contain vinegar or salt.

After some experimentation, you will probably find that the vinegar and salt are the important ingredients but are they both necessary? Lets find out. Start with four small cups. Put about an inch of water in one. That will be our control. The control does not contain any of the chemicals that we are testing. If it cleans the pennies too that would tell us that the reaction happens, even without the vinegar or salt. Label this cup "Control."

In the second cup, put about an inch of vinegar. Label this one "Vinegar."

In the third cup, put about an inch of water, and then add a teaspoon of salt. Give it a quick stir to dissolve the salt. Label this one "Salt Water."

In the fourth cup, put about an inch of vinegar, and add a teaspoon of salt. Give it a quick stir to dissolve the salt. Label this cup "Vinegar and Salt."

Now, you are ready to do some testing. Lets start with the Control. Dip one of the tarnished pennies halfway into the water, and hold it there for 30 seconds. Remove it from the water, rinse it, and put it beside the Control cup.

Do the same for each of the other cups. Be sure to give each 30 seconds, and be sure to rinse the penny to remove any vinegar or salt. Place each penny beside the solution you used to test it.

Results

OK, now what did you find? If your results were like mine, you found that neither the water, the vinegar, or the salt water did much, if anything to the pennies. The mixture of salt and vinegar was very effective at removing the tarnish.

So what is happening? The tarnish on the penny is copper oxide, and a chemical reaction with the vinegar will actually dissolve it. Then why did the pure vinegar not work? With the penny and the vinegar, you get a series of chemical reactions that form a circle. One reaction removes the copper, but just as quickly, another reaction puts it back. In chemistry, this is known as an equilibrium reaction.

The trick is to add something that will interrupt that equilibrium. You want a chemical that will grab the copper before it can be put back, and the table salt does a very good job of that.

What is it about the table salt that grabs the copper? Table salt is sodium chloride. When you put it in water, it separates into sodium ions (charged atoms) and chlorine ions, but is it the sodium or the chlorine that grabs the copper. An easy way to test that is with a different kind of salt. One of the common salt substitutes is potassium chloride. You can find it beside the regular (sodium chloride) salt at the grocery. In a fifth cup, put about an inch of vinegar and stir in a teaspoon of potassium chloride. Does it work the same as the table salt? If so, then it is the chlorine that grabs the copper. If not, then it is either the sodium, or the combination of sodium and chlorine.

You can look deeper into the vinegar as well. Will it work with other acids? Try using lemon juice (citric acid and ascorbic acid) or carbonated drinks (carbonic acid). Carbonated colas also contain phosphoric acid. Again, remember safety. Look for acids from your refrigerator and spice cabinet, not from other household chemicals.

Link to Penny Chemistry, part 2

This is another of those fun bits of science that many of us think we understand until we really start to look at it. To try this, you will need:

- water
- two drinking glasses
- a saucer or cover for one of the glasses

Start by taking a glass of water outside. Find a nice, flat spot on your driveway or sidewalk, and pour out the water to make a big, wet spot. Now go for a walk, have a snack, read a chapter in your favorite book, have another snack, and then go back to look at the wet spot. Is it still there?

That will depend on the weather. If it is a very humid day, then it may still be there. If it is cold enough, your wet spot may still be there as a patch of ice. On the other hand, if it is a dry day, especially if it is warm or windy, then you will probably find that the water is all gone. Where did it go? It evaporated of course. But, what happens when a liquid evaporates?

When a substance evaporates, it changes from its liquid form to its gaseous form. Isn't that the same as boiling? But, water has to be hot for it to boil, yet it will evaporate even if the weather is near freezing. How can that be? What is the difference between boiling and evaporating?

The basic process is the same. If the molecules of the liquid have enough energy, they can break away from the rest of the group, launching themselves into the air to become a gas. The difference between the boiling and evaporating is in where the molecules get that energy.

For boiling, the energy comes from heat. Put a pot of water on the stove, turn on the heat, and soon the water molecules in the pot will gain enough heat energy to let them break away in large numbers.

But, if you take that same pot of water, and put it on the table instead, it will still evaporate. Why? Those water molecules are bouncing around, bumping into each other. When they bump, energy can be transferred from one to another, just like the balls on a pool table. If the bumped molecule is in the middle of the pot, it will probably bump into another water molecule, passing along the energy, but if it happens to be at the surface, that bump could give it enough energy to break free. It evaporated!

Notice that you did not have to heat the water to the boiling point. Even if the water is very cold, you will still have molecules at the surface that get bumped hard enough to let them evaporate.

Now, for the next step, fill two glasses half-full of water (or half-empty if you happen to look at things that way.) Put them someplace where they can stay for a few days without being in the way. Cover one with the saucer, and leave the other open.

After a few days, what do you think will happen? The water in the uncovered glass will probably evaporate away, but the water in the covered glass will still be there. Why? Does covering the glass stop the process of evaporation? No. Instead, it increases something else to balance the evaporation. Condensation.

Think back to that molecule of water that was bumped free. It is now bouncing around with the other molecules in the air. If it bounces in the right direction, it could bump back into the surface of the water. If that happens, it can stick, giving up some of its extra energy, and changing back into the liquid form of water.

In the covered glass, the water continues to evaporate just as quickly as it does in the open glass. Because the glass is closed, the number of water molecules in the air increases, meaning more and more of them will bump back into the water, changing back to a liquid. You quickly reach the point where things balance. There are just as many water molecules condensing back to water as there are evaporating into the air. So covering the glass does not stop it from evaporating. Instead, it keeps the water vapor in place, so it can bump back into the liquid again.

Now, thinking about that, why would a windy day make your water evaporate faster? If the air is still, then it is easy for a water molecule to be bumped free, rebound from an air molecule, and rejoin the water. On the other hand, if the air is moving, the water molecule may be moved away from the liquid before it bounces back. The water molecules don't leave any faster. They just have a much smaller chance of bouncing back to the liquid, so the puddle dries up faster.

Have a wonder-filled week.

This week's experiment comes from Burning Questions, my program on the science of fire. When teaching about fire, educators frequently talk about the fire triangle to teach about how things burn. Just as a triangle has to have three sides to be a triangle, you need three things to have a fire: Fuel, heat, and oxygen. Recently, fire educators have started teaching about the fire diamond instead of the fire triangle, because sometimes having fuel, heat and oxygen is not enough to get a fire. To see this, you will need:

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As much as I would have liked to do another experiment with chocolate, I don't really have time to go buy a larger belt, so this week's experiment is related to fireworks instead. If you are in the USA, you are probably going to see fireworks for July 4th. Have you ever wondered how they get the different colors into the fireworks? If you want yellow fire, do you add yellow paint to the mixture? No, that would not work. To see how the colors get into fireworks, you will need:

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Two weeks ago, I mentioned that I had a lot of fun experimenting with carbonated soda (and drinking it) and that I should do an experiment with chocolate. I got quite a few e-mails suggesting experiments with chocolate, but this one was the most common. It has to do with the white discoloration that you sometimes find on old chocolate. For this week's experiment, you will need:

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It is hurricane season here in Florida, but luckily this has been a very calm season so far. We still have to be sure to be prepared, just in case. I came across the idea for this experiment while reviewing some of the emergency information. Often during hurricanes, the water supply is contaminated and it is necessary to boil your water before drinking it. All of the information sheets say that this makes the water taste flat and they give several different ways to "fix" the taste. To see how boiling changes the taste, you will need:

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The Wonders of Ice

Explore why ice is one of the strangest solids we know of.