Glad you wrote to us with such an interesting question. I usually study marine animals and plants that make light (kinda like fireflies, if you have seen them?) and glow in the dark! If you would like to learn about these plants and animals that bioluminescece (pronounced BI-O-LOOM-IN-ES), go to this website (http://lifesci.ucsb.edu/~biolum/). This is another part of science that is really interesting!

To answer your question about bones, I did some internet research, and came up with the following reply. I found out from the following site (http://cpmcnet.columbia.edu/texts/guide/hmg05_0009.html),
that after your stomach breaks down the food you eat (let's say it is milk that you drank, which has lots of calcium!) it goes to the next organ, called the small intestine. The food can then be taken into into your bloodstream there. Calcium travels around in your blood as very small particles and can be placed in different parts of your body, where you need calcium.

Did you know there are MANY uses for calcium in your body besides forming your bones? (Although as you learned from your rubber bone experiment, that is very important for us to be able to stand and walk!) Calcium is needed so that you can move your muscles, and so that messages can be sent through your nerves to different parts of your body and brain? Adults have 2 pounds of calcium in their bodies!

Once calcium is in your bloodstream, some of it is collected from the blood by special cells called osteoblasts (pronounced AHST-E-O-BLASTS) that create your bone structure (calcium with phosphorus crystals and collagen proteins, a very strong material). There are also cells called osteoclasts (pronounced AHST-E-O-CLASTS) that break down your bones. This build up and breakdown of bones is something that happens all the time in your body, because your bones are living organs!

There are many more bone-builders than bone break-down cells when you are young, so you form good, strong bones! When some people get older, they develop weakened bones that are easier to break because more bone break-down is happening than bone-building! Scientists are trying very hard to find medicines that will help these people's bones not break so easily.

Here's a website that your Mom can help you read about bones, and the disease that makes older people's bones fragile:
http://www.health-science.com/calcium.htm

Good luck !

Neat question!I hope your chicken bones come out really rubbery. They're lots of fun that way!

Anyway, your bones are hard because of the this stuff called calcium carbonate. It's a big word, but all it means is that two things, calcium and carbonate, "stick" together to make your bones hard. Did you also know that calcium carbonate is the same as chalk your teacher uses to write on the chalkboard? Pretty neat, eh!

Anyway, when you drink milk, it goes to your stomach and stays there until your body is done with it. When it is in your stomach, all the goodies which are in the milk, including calcium, are taken out of the milk and absorbed by your stomach. How does that work? Well, your stomach has special little things stuck to its walls (called transporters) which absorb the calcium and other goodies and sends them to your blood. Pretty neat, right? Then your blood carries that calcium to your bones, where it dumps off the calcium for your body to make more bone. That's basically how that
works.

Now here's another neat trick. If you have a small piece of chalk, drop it in the vinegar and watch what happens. Pretty neat! Is there any chalk left after a while? Probably not. Remember how I told you that chalk and your bones are made of the same stuff (called calcium carbonate)? Well, when you put a chicken bone in vinegar, it dissolves away the calcium carbonate, just like the chalk gets dissolved! That's why the bone is all soft. Remember that your bone is made of more things besides that
calcium carbonate, that's why your bone didn't completely disappear. But because the calcium carbonate is gone, your bones are soft. I hope your project goes well!

I'm writing from Wisconsin, the dairy state, so I'll tell you about calcium. Our bodies use calcium in a lot of ways. Calcium helps our heart beat and helps our muscles move. It also makes up part of our skeletons. As you say, you eat cheese and drink milk. The calcium goes into your small intestine (gut) along with the rest of your food. Then it is absorbed into your blood right through the walls of your gut. When that blood passes through your bones, little bone-building cells grab onto it and make bone out of it. Your body is constantly breaking down your bones and building them up again. The bones you use more get stronger. Their shape even changes a little.

Heavy exercise can actually break down your bones. There's a great article on losing calcium through sweating at:
http://whyfiles.news.wisc.edu/055oddball/sweat.html

Thanks for asking,