Screaming Balloon

What you need:

Balloon

Hex nuts

What you need to do:

1. Squeeze the hex nut through the mouth of the balloon. Make sure the hex nut goes all the way into the balloon so that there is no danger of it being sucked out while blowing up the balloon.

2. Blow up the balloon and tie it off.

3. Spin the balloon then stabilize it once the hex nuts spins in the balloon. Listen to the sound. Do you hear your balloon screams?

Results:

This is actually a 2 for 1 experiment - you're learning about the science of motion and sound. The hex nut circles inside the balloon due to centripetal force. Centripetal force is the inward force on a body that causes it to move in a circular path. It is a "center-seeking" force. A hex nut has 6 sides, and these flat edges cause the hex nut to bounce or vibrate inside the balloon. The screaming sound is made by the sides of the hex nut vibrating against the inside wall of the balloon. To prove this, repeat the experiment using a coin in place of the hex nut. While the coin spins beautifully inside the balloon, the "spooky" sound is gone. Thanks to Steve Spangler for the explanation.

Discussion with my girls:

They were so petrified with the screaming sound that made them automatically jumped to me. They asked me what happened. I told them the sound was coming from the balloon. I told them in the simplest form, "Bila kita pusing-pusingkan belon, nut tu akan bergerak dan langgar dinding belon. Sebab tu-lah jadi bunyi yang spooky tu." Then suddenly the balloon popped! And we discovered the pinkish stain on the hex nuts. The proof made my work easy and they believe in science even more. Iesha concluded, "Haa, betul-lah nut berlanggar dengan belon. Tengok, belon pink ni melekat kat nut."