Water in a Straw

Many students know that if you put your finger over the top of a straw while it is in a fluid, you can pick the straw up and the fluid will remain in the straw. This activity helps students make the connection between this phenomenon and what they have learned about the omnidirectional nature of pressure.

Water in a Cup

In this activity, students apply what they have learned to a counter-intuitive phenomenon: that water turned upside down in a cup with a card across the cup stays in the cup! This activity reinforces the concept that air pressure acts omnidirectionally.

Why Does the Top Fly Off of the Teapot?

Students are asked to reason about what is happening when air is blown into a plastic teapot, resulting in the top flying off. Many people think that air pressure pushes down. If this were true, how can the lid pop up? This activity reinforces the concept that pressure acts omnidirectionally and that increasing the pressure inside the teapot causes the lid to pop off.

The Squished Cup: Is Water Pressure Unidirectional or Omnidirectional?

In this activity, students are shown a picture of a Styrofoam cup and a picture of a similar cup that was brought to a depth of 1770 ft. underwater. They are asked to consider what the evidence suggests about the nature of water pressure as an analogy to air pressure.