Send Water Uphill!

Show your child the "supernatural" potential found in the combination of air, water pressure, and gravity. Your little scientist will create a siphon using two buckets, plastic tubing, and water. Watch her astonishment as she sees the water travel "uphill" through the tubing! It is probably best to perform this trick in a kitchen or bathroom, where any spills can be easily cleaned up.

What You Need:

• Two large transparent bowls
• Clear plastic tubing long enough to comfortably go from one container to the other (available from a hardware store or aquarium supply store)
• Food coloring for better visibility (optional)
• Large jug of water
• Two surfaces (close together, one lower than the other)

What You Do:

1. Ask your child to mix the food coloring into the water in the jug and to pour the water into one of the glasses.
2. Two surfaces are needed, with one lower than the other (a table and chair work well).
3. Have your child place the empty bowl on the lower surface.
4. Invite her to put the bowl of colored water on the higher level surface and to place one end of tubing into this bowl.
5. Ask your child to fill the tube with water, either by pouring from the jug or by sucking form the glass (if you are planning on letting your child put her mouth on the tubing, make sure that it is non-toxic).
6. Once the tube is full of water, the open end should go into the empty bowl. Ask your child to put her finger over the end of the water-filled tube as she make the transfer.
7. Water will "siphon" out of the higher bowl into the lower empty bowl.
8. Now, to make the water flow more obviously "uphill." Ask your child to carefully raise the middle part of the tube so that it is higher than the bowl set on the higher surface. Also, drape the tubing over the back of the chair on which the lower bowl is sitting, so the tube goes up over the chair before entering the lower bowl. Make sure that the ends of the tube remain in the two bowls and that there is still plenty of water in the upper bowl. The water should continue to flow into the lower bowl, even though it has to first go uphill!

What's Happening?

The siphon works because of the difference in pressure. The water flows from the higher pressure in the upper bowl to the lower pressure in the lower bowl, yet still goes "uphill" before flowing down.

Now What?

Now have your child place the second bowl on an even higher surface than the table. See what happens! Encourage your child to record her observations when the experiment is varied.

With your child, brainstorm other ways a siphon can be used!