Do you think that you can get a regular drinking straw to go through a hard raw potato? It doesn’t seem possible, does it? While it may sound impossible, with a little scientific “magic,” it can easily be done!
Kids can test their strength and learn about air pressure in this super easy science experiment. Pick your potato, print your instruction sheet below and discuss the scientific explanation behind how this experiment works all while having fun!
- Drinking Straw
Step 1 – First, prepare your straw. If you have a straw that has a bendable top, cut off the top portion of the straw so you are left with a section that isn’t bendable. Then make some observations about the potato and the straw. Is the straw hard? Does it bend easily? What about the potato, is it hard or soft? Do you think the straw is strong enough to stab the potato? Write down your hypothesis (prediction) and then follow the steps below.
Step 2 – Next, attempt to stab the potato with the straw. You may get the straw to pierce the skin of the potato, but it will likely not go into the potato very far. Do you think there is anything you could do to get the straw to stick deeper into the potato?
Step 3 – On your second attempt, place your thumb over the far end of the straw. Keep your thumb there and stab the potato with the straw again.
Step 5 – This time, with no more effort than before the straw will sink deep within the potato. You may even get it to go completely through the potato. Do you know what caused the straw to stick further into the potato? Find out the answer in the how does this experiment work section below.
Air pressure is the secret to this experiment!
On your first attempt to stab the potato with the straw, the air inside the straw was pushed out of the top of the straw when it came into contact with the potato. As a result, the straw just barely stuck into the skin of the potato.
On your second attempt to stab the potato with the straw, when the straw hits the potato, the air trapped in the straw (by your thumb) gets compressed and pushes out against the straw making it more rigid. Because of this, the straw is strong enough to go through the potato!
I hope you enjoyed the experiment. Here are some printable instructions: