Science Projects Index

Urine and the Disposal of Body Wastes

Urine collects many of the wastes products and impurities that are collected in the blood and disposes them.

To see this take some hot water in a tray and dissolve some salt in it. Leave the dish open for a day or two.

You will find that the water has evaporated and the salt remaining in the dish. So, same way, the urine also has dissolved impurities in it.

How Do Our Lungs Expand?

Take a plastic bottle and cut off its bottom.

Through the top of the bottle insert a balloon and tie its mouth around the bottle's neck with a string so that the balloon is open.

Take another balloon and cut off its upper part that contains the mouth. Fasten it around the bottom of the bottle as in a drum.

Now pull this lower balloon covering down. You will find the balloon inside the bottle expanding inside the bottle, as if someone is blowing air into it. This is how our lungs expand when our diaphragm is drawn down.