You start with a plastic soda or gatorade bottle. If you use the gatorade bottle, you need to drill a hole in the cap to insert the straw. For the soda bottle, just use the bottle as is without the cap. CAUTION: water bottles will not work! We found out the hard way that water bottles will not work. The manufacturers have taken so much plastic out of the water bottles that they are very thin walled. The walls are not strong enough to resist the pressure changes and they will not work.
You will also need a mixture of rubbing alcohol (1 to 1 ratio), a straw, and clay. I also have a bucket of ice on hand, containers for iced water and very warm water, say 110 degrees or so.
Here is copy of the sheet that I use:
- Cup your hands around the bottom of the bottle and see if the water/alcohol in the straw rises. What is the approximate temperature of your body? What is approximate room temperature? What is the difference between the two?
- Put the bottom of the bottle in warm water, what happens? What happens if you put it in ice water. Keep observing the bottle, does something interesting happen in the alcohol/water mixture?
- Why does the water/alcohol in the straw go up and down with temperature?