Mixtures are very interesting because they can dramatically change the properties of whenever ingredients are included (whatever is being mixed). But have you ever wondered why you were supposed to mix water with antifreeze? Water will freeze at 32 degrees. Antifreeze will freeze at around 10 degrees. But if you mix them together, the mixture won't freeze until around -40 degrees. Of course, this depends on the ratio of water to antifreeze and the type of antifreeze.

Our air is a mixture of Nitrogen and Oxygen, along with some other gasses. By itself, Oxygen is very flammable, but when mixed (ex. air), it only helps other things burn, such as wood. Wood will not burn if oxygen (from air) isn't present. Glass is normally clear and easily fractured, but if you add things to it, you can make it hard to break (add Boron to make Pyrex), or very colorful (Cobalt makes a wonderful blue color). Sometimes these are called impurities, but they are still mixtures.

There are several types of mixtures. If you're a parent, you're probably familiar with a suspension. Children's cough syrups are being made as a suspension because it hides the taste of the medicine. The medicine particles are mixed with syrup particles. Suspensions have the largest particle size of any mixture, and can separate out. An oil and vinegar dressing is another type of suspension. If you have a medium particle size, you were dealing with a colloid. There are many examples of colloids in food. These tend to be more stable, taking months to separate out under normal conditions. Butter, Jell-O, and mayonnaise are all common colloids. The mixture with the smallest particle size, sometimes down to one atom, is called a solution. These will not separate matter how long they sit. Sugar water is a good example of this. As long as the water doesn't evaporate, you keep your mixture. If the water evaporates, though, you are left with just your sugar. Rock candy is made this way - the slow separation of the sugar water through evaporation. Bleach is another. That is sodium hypochlorite in water. Tea and house paint are both mixtures-can you tell what kind? Take a guess in the discussion area.

If you combine to molten metals stir them up you get a totally new type of metal called an alloy. Those metals are not chemically bound together, but the alloy is frequently very different than the original metals themselves. Aluminum is very light weight, but can't handle a lot of pressure. If you mix aluminum with copper, you now have a very light weight metal that can handle the compression needed for airplane frames.

Some alloys are metals mixed with non-metals. Steel is a perfect example. Iron is hard, but when mixed with carbon, it makes a much harder alloy (steel). Different amounts of carbon affect the strength and properties of the steel. Alloys have been so important to mankind that we described entire historical ages by the alley discovered at that time (Bronze Age). On the periodic table, 86 of the elements are metals. Only four of these are found pure in nature. The rest come in some form of ore compound. The pure metal can be taken from those however. That process makes it really easy to continue on making an alloy. Can you name any other alloys? Why do you think that alloy was created?