Science Smarts: The sneaky strength of air

By Patty Rooks on March 15, 2025.

Can you believe we are only a week away from the 50th Anniversary of the Regional Science Fair? It has been a busy week, but amazing – I have seen so many creative, ingenious and well thought out science fair projects at the schools in southeastern Alberta. I cannot tell you this enough; we have some pretty amazing youth in our communities!

How do they come up with these projects? Well, I am running out of time this week for “desk work” as I am off to another school in a few minutes, so the activity will have to be a quick one. Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– Drinking straws (preferably a plastic one if you can still find one)

– Raw potato

Procedure

1. The first thing I want to do is tell you to be careful. Please do not slip and stab yourself with the straw. Follow all instructions carefully.

2. Hold the drinking straw in your hand, gripping it between your fingers. DO NOT cover the hole at the top.

3. Try to stab the potato.

4. What happens?

5. Repeat this experiment BUT cover the straw hole with your thumb.

6. What happens this time?

What is going on?

The first attempt at stabbing the potato likely did not go well. When you placed your thumb over the hole in the straw, the chances of you piercing through the potato increase. When you cover the straw with your thumb and trap the air inside, this trapped air increases the strength of the straw and as a result it is much more sturdy and able to pierce through the tough potato.

If you do not trap the air in the straw, it is pushed out and the straw is not nearly as strong and likely bends and will not go through the potato. Be careful you do not stab the potato in the “eyes!”

If you have any questions with regards to Science Fair, do not hesitate to email me anytime at Praxis.

Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

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