STEM Activity: Poking Potatoes

Did you know that jack-o’-lanterns were originally carved from root vegetables like turnips? The tradition is rooted in a legend about “Stingy Jack,” or “Jack of the Lantern,” a man who was cursed to wander the Earth for eternity, with nothing to light his way but a hollowed-out turnip with a burning ember inside it. In Europe, people carved faces into turnips and potatoes to scare away wicked spirits like Stingy Jack.

When Irish and Scottish immigrants came to North America, they brought this tradition with them, adding a new-world twist when they discovered that pumpkins were much easier to carve.

Try your hand at a more traditional jack-o’-lantern for Halloween this year – and explore science at the same time – by carving a potato using nothing but a straw.

Materials Needed:

• Potato
• Paper or plastic straw

Step-by-Step Instructions:

1. If you have a bendable straw, cut off the part of the straw that bends.
    
2. Hold the potato on the opposite side of where you’re getting ready to poke, and make sure your fingers are not in the path of the straw.
    
3. Try to poke the potato with your straw, being careful not to push so hard that you bend it. Your straw may be able to pierce the skin, but likely isn’t able to go very far into the potato.
    
4. Place your thumb or finger firmly over one end of the straw and try poking the potato with the straw again. This time, it should go into the potato much more easily!
    
5. Repeat the process of poking the potato with the straw in a pattern of your choosing to create your own jack-o’-lantern face.

What Are We Discovering?

This activity is all about air pressure! The first time you tried to poke the potato with your straw, the air inside the straw was able to escape through the top. As a result, there was nothing helping the straw as you pushed it against the potato.

When you sealed one end of the straw with your finger, it trapped the air inside. This greatly strengthened the straw and helped it push farther into the potato.

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