Depending on how easy you want the working model to be, these are a few you might like to try:
- The easiest is to make a string phone with paper cups and demonstrate the use of sound waves.
For this project, all you need is two paper cups, some string
(fishing lines are good, as is kite string) and something to poke a hole
in the bottom of the cups.
Use about 15 metres of string and thread it through the hole in each cup, then tie a knot so that it doesn't come out.
Get your friend to stand away from you and stretch the string tight. You should be able to hear your friend when he/she talks into the cup.
- You could make a model of a hand showing how muscles and tendons work.
For this, simply draw around your hand on a piece of card and cut it out. Cut five pieces of string which are the length of your hand. Attach the string to the tip of each finger (and thumb) and also to the base of the palm.
Staple the string at the same points as your joints are in your fingers. Pull on the strings at the base of the palm, and this will show how muscles work.
- Make a rain gauge with a plastic bottle, stones and water.
Take a plastic bottle and cut off the top. Put some pebbles in the bottom of the bottle. Insert the top of the bottle that you cut off earlier, upside down into the top of the bottle and attach with tape. With a marker pen and ruler, draw a scale on the side of the bottle.
Pour water into the bottom until it reaches the bottom strip on the gauge and then put the bottle outside until it rains!
After a rain shower, check to see how much more water is in the bottle. You can monitor this over days, weeks or months.
Good luck with your project, let me know how you get on :-)