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Simple Electrolysis

The power of electricity can tear water molecules apart.

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A fun but smelly test to find tannins in your food.

This week, we are going on a hunt. No, we are not hunting for birds on wires, as I did for this week's video. Instead, we are hunting for acid. The word "acid" usually makes people think of dangerous chemicals, burning and corroding, but it describes an entire range of chemicals.

OK, so where are we going to look for acids? Not in your car, although there is acid in the car battery. Instead, we will look for acids in your refrigerator. The refrigerator! What would acid be doing in there? As we shall see, it is sitting there waiting for you to consume it.

Before we start hunting, we really should know what an acid is. A chemist will tell you that an acid is a chemical that will give up a hydrogen ion to another compound, called a base. That may seem complicated, but there is an easier way to identify acids. All we have to do is look at the word itself. Acid comes from acidus, the Latin word for sour. Acids have a sour taste.

Taste! Wait a minute! Don't try tasting battery acid, or for that matter, any chemical that is just lying around. We will limit our tasting to the things in your refrigerator, but don't worry. We will find plenty of acids there.

Now comes the fun part. Go open the refrigerator door, and we will start our hunt. Lets begin with the easy things. What do you see that has a sour taste?

If your refrigerator is like mine, the first thing you will see is a jar of pickles. Actually, in my refrigerator, you would see five or six jars of pickles, because I really like pickles. What do pickles taste like? Sour, right? Even sweet pickles have a sour taste, mixed with the sweet. Don't take my word for it. Have a pickle. What makes pickles taste sour? Vinegar, and most of the flavor of vinegar comes from acetic acid. As you taste your way though the refrigerator, you should find all sorts of things that contain vinegar, from salad dressings to hot sauces to mustards.

OK, now what else in here tastes sour? What about that lemon hiding down there on the bottom shelf? Lemons are certainly sour, which means they should contain acid, and they do. The acid in a lemon is citric acid, which makes sense since lemons are citrus fruit. Citric acid is found in other citrus fruits, such as limes, and grapefruits, but it is also a common ingredient in jams, jellies, canned fruit, and even soft drinks. While you are in the refrigerator, be sure to taste all those too.

We have found two abundant acids, but don't stop now. Those soft drinks contain another kind of acid called carbonic acid. Carbonic acid is formed when you dissolve carbon dioxide in water, so anything that is carbonated contains this acid.

The citrus fruits also contain ascorbic acid, also known as vitamin C. If you have ever taken vitamin C tables, you will remember the sour taste. Ascorbic acid is present in tomatoes and many other fruits and vegetables.

Looking on down the shelves, you might see a carton of sour cream. A quick taste will tell you that it lives up to its name, so it must contain acid, and it does. In this case, it contains lactic acid, an acid formed when milk spoils, which is why we say that the milk has soured. It is also the acid that gives yogurt it’s pleasantly tart flavor.

If you happen to have any strawberry rhubarb pie, the tartness of the rhubarb comes from oxalic acid, which is also present in spinach, beets, many kinds of berries, and even in chocolate.

If you continue tasting and reading labels you will come across several other acids, but by now you should realize how large a role acids play in the flavors of our food. Even that bowl of cherry ice cream that is waiting for me contains citric acid, ascorbic acid, and oxalic acid.

Do limit your tasting to the yummy stuff in the refrigerator (and the freezer where the ice cream is kept), but since practically everything in your refrigerator contains at least a little acid of some kind, you should have no trouble satisfying any sour cravings. Well, my ice cream is melting and the chocolate sauce is calling, so I will stop for now.

Have a wonder-filled week.

Two weeks ago, we took the first steps in learning about how soap was once made by using water to dissolve potassium hydroxide out of paper ashes. You can find part one at: http://thehappyscientist.com/science-experiment/wood-ash

If we had been serious about making soap, we would have used a lot more ashes, probably from a wood fire. We would have dissolved the potassium hydroxide in water and then would have boiled the water to concentrate the chemicals.

Once we had a strong solution, we would have mixed the strong base with fat or oil for a process called saponification. The result would have been soap.

This week, we will do something very similar, on a much smaller scale. To try this, you will need:

- a dirty sink
- a sponge
- a porcelain cleaner that contains bleach. I used a product called Soft Scrub with bleach and it worked very well. Comet Cleanser with bleach also worked very well.

First, be careful. Anything that contains bleach can leave white, bleached spots on clothing, and can irritate your eyes.

Wet the sponge and the sink. Apply the cleaner with the sponge. Be sure to follow the directions on the package, and use it properly. Then scrub the sink. Do a good job, and get all the corners.

When you are done, rinse the sink well. While your fingers are wet, rub them together. They should feel very slippery. That slippery feeling is the result of saponification. The bleach in the cleaner is sodium hypochlorite, a strong base, just as potassium hydroxide is. A strong base will react with the fatty acids in the fat to produce soap and glycerol.

Soap? Did we really just make soap? Yes that slippery feeling is the result of saponification of the oils in your skin. The same basic process is used in oven cleaners and chemicals to open clogged drains. A strong base will convert the grease in the oven or drain into soap, which can be washed away.

Now, to make any of that into a really nice, useable soap, it would take more processing to balance the fat with the basic chemical, and then remove the impurities. Still, you really did make a tiny bit of soap. I do not recommend the process for cleaning your hands, but you are sure to get compliments on the nice, clean sink. If you want to experiment more, I am sure that the tub could use cleaning too. You might even earn a nice bowl of ice cream.

Have a wonder-filled week.

This week's experiment comes from an article I read on technological developments. While reading about ways to make iron, glass, and other historic processes, I became fascinated about the section on soap making. Now, we will not go through the entire process of making soap (at least not this week), but we will experiment with the first steps in classic soap making. To do that, you will need:

- a sheet of writing or typing paper
- a butane lighter
- aluminum foil
- two disposable cups
- isopropyl alcohol (rubbing alcohol)
- turmeric spice

In classic soap making, done the way it was two hundred years ago, you need some potassium hydroxide, which will be combined with fat to produce the soap. Luckily, potassium hydroxide can be recovered from a substance which was very common for pioneer families. Wood ash. The ashes left behind from burning plant material contain calcium carbonate, potassium hydroxide, and sodium hydroxide. Different plants produce different quantities of each, and hardwood ash is the best for potassium hydroxide.

Instead of building a hardwood fire, we will burn some paper. Think about it. What is paper made of? Wood. So burning the paper will leave behind ash that contains the potassium hydroxide that we want.

Now, don't rush to start burning the paper. First, tear off about an inch of one corner and set it aside for later. Also, we don't want to accidentally burn anything besides the paper. To be safe, place a sheet of aluminum foil in the bottom of your sink. Then crumple a sheet of paper into a loose ball, and place it in the center of the foil. Warn any other people in the area that you are going to burn the paper, because the smell of something burning can alarm people if they are not expecting it. That can wind up with you getting in trouble, which is a bad thing.

Once everyone is warned, use the butane lighter to set the paper on fire. Wait for the flame to burn down. The paper will turn black, and then at the edges, it will start to turn white. That white is what we want, so we will help it along a bit. Use the butane lighter to heat the black areas a bit, so they will burn completely, giving you more of the white ash. You don't need all the black to turn white, so don't use up your lighter. Once about 1/4 of the remains are light grey or white, let the rest of the fire go out, and wait for the foil to cool. Then pour the ash into one of the disposable cups. Add about a teaspoon of water, and swirl the water around to mix it well. Set this aside. Keep the foil, as we will need it later too.

In the other disposable cup, put about a tablespoon of rubbing alcohol. Then add about 1/8 teaspoon of turmeric. Turmeric is a spice that you can find at the grocery. Be careful with the turmeric, as it will stain clothing, skin, and just about anything else (which is why we are using disposable cups.)

If you remember back to video 16, Making Turmeric Paper ( http://thehappyscientist.com/science-video/making-turmeric-paper ), you will remember that turmeric acts as an indicator, turning red in the presence of a base. Potassium hydroxide is a strong base, so if our ash contains potassium hydroxide, then it should cause the turmeric to change colors. To test that, pour a couple of drops of the ash/water mixture onto the foil. Then add a couple of drops of the turmeric/alcohol mix. Watch as the two mix. It should turn a deep red, indicating that the ash/water mix is a strong base.

But wait a minute. Maybe the paper was basic to start with. That is why we tore the corner off the paper. Place that corner onto the foil and add a couple of drops of the turmeric solution. It colors the paper yellow, not red, showing that the base was produced when the paper burned.

If we were going to make soap, we would need a LOT of ash. Then we would filter water through it to remove the potassium hydroxide. That water would be collected and boiled to concentrate it. Once we had a very concentrated solution, it would be mixed with rendered fat, forming soap. That is a long, messy, smelly process, so we will stop here for now. Instead, I will work on another mixture, involving ice cream and chocolate syrup, which usually leads to the need for some soap.

Have a wonder-filled week.

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Can you mix two clear liquids to produce a black liquid? Of course you can!

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A continuation of video 120. This time we will mix two clear liquids to form a white liquid. Then we mix that with the black liquid from last time, to wind up with a clear liquid again.