Hooked on Science: Air pressure can make water rise

Usually it takes a lot of rain to force water to rise, but you can do the same thing by creating a difference in air pressure.

Materials

* Candle

* Matches

* Pie pan

* A transparent glass

Instructions

STEP 1: Place the candle in the center of the pie pan.

STEP 2: Fill the pie pan with water.

STEP 3: Using a match, ignite the candle and then quickly place the transparent glass over the candle, allowing the top of the transparent glass to rest on the bottom of the pie pan.

Explanation

The air inside the transparent glass is heated, which causes the water to expand. When this happens, an area of lower air pressure forms on the inside of the transparent glass. The air pressure on the outside of the transparent glass is now greater. This greater area of air pressure pushes down on the water forcing the water into the transparent glass.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments that might get you hooked on science. Send him your science questions at jlindsey@hookedonsciencecom. More science experiments can be found at www.semisourian.com.