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Water Moves Uphill

Make a little river move uphill.


- two glasses or cups
- water
- straw
-a few books


Fill one glass with water and place it on a few book.

Place the empty glass right next to the full glass, in order to reached by the straw.

Put one end of the straw into the water and suck at the other end, until the straw is filled with water. Close this end with your finger.

Place the closed end over the empty glass and release your finger. What happens?


The water flows first uphill out of the glass and after downhill into the empty glass. Usually water does not flow uphill. In this case we are filling the straw with water. You are sucking water into the straw. The water which is now in the "downhill part" of the straw reaches downhill. Therefore the down flowing water sucks the water out of the full glass. The straw is completely filled with water. The down flowing water has to be replace with anything, because there cannot be nothing inside the straw. So it will be replace by water of the upper glass. Therefore it is very important to keep the straw's end under the surface of the full glass.