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Updated on Feb 06, 2012

Grade Level: 6th - 8th; Type: Physical Science

Students will create an uphill flow of water by using a siphon.

  • What forces are acting on the liquids?
  • How is a vacuum created?

What goes up must come down. You wouldn’t think this would help us explain how water can flow uphill. To drink a glass of water you must raise the glass above your mouth. The water is pulled down by gravity into your mouth. What’s another way to drink a glass of water without lifting the glass? Use a straw. A straw creates a vacuum, or negative pressure, so water is pulled up the straw. We can use these principles to create an uphill flow of water.

  • 1+ gallon bucket (2)
  • Water
  • Clear tubing approximately 3 feet in length (can be found in a science lab or purchased at a hardware store)

  1. Place one bucket on a stool and the other bucket on the ground.
  2. Fill the top bucket with water.
  3. Place one end of the tube in the top bucket, submerged in the water at the base.
  4. Create a vacuum on the opposite end by suctioning the water up the tube like drinking from a straw.
  5. Once water gets to the end of the tube immediately place it in the bottom bucket.
  6. What happens? In what direction does the water travel?
  7. Now reverse making the water flow up into the top bucket.
  8. Fill the bottom bucket with water. The top bucket should be empty.
  9. Place one end of the tubing in the bottom bucket and create a vacuum.
  10. Once the water reaches the other end of the tube immediately place it in the top bucket, near the base.
  11. What happens? Does the water travel in the same direction?

Terms/Concepts: Atmospheric pressure; Vacuum; Siphon

Melissa Bautista is a research scientist, freelance editor, and writer, with a focus in Neuroscience. She believes in establishing solid foundations in education through experience, creativity, and collaboration. She is fascinated by pedagogy and the concept of learning through living.

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