No birthday party is complete without balloons and straws. And after every party there usually are some left over balloons which never got put to use. Instead of putting them away and eventually losing sight of them, I suggest using them for some quick fun science experiments. This fun experiment can be tried by everyone in the family, from the oldest to the youngest member.
Name: SPIN-IN-CIRCLE BALLOON
Concept: Air thrust
- Straw (Bendy one preferred to Regular but both work well)
- Rubber band / Sticky Tape
- If you’re using a bendable straw, cut straw on longer stem making it equal to length of bendable part. Now, you should have a straw in shape of V with 2 equally measuring arms.
- If you’re using a straight straw, cut in half and use 1 half of straw. Discard the other half or put away for later use.
- Fit one end of straw into the mouth (nozzle) of the balloon and fold the balloon mouth over it. Seal the balloon mouth over the straw with a rubber band or sticky tape making sure the air does not escape.
- When using rubber band make sure that it doesn’t squeeze it too hard. Seal the balloon just right and make sure the straw isn’t squeezed or bent tightly. (See picture below)
- Blow air into the balloon using the open straw end and fill it up.
- Place your finger at the open end of the straw so that air does not escape.
- Place the balloon on the floor and let go.
You will see that it will spin beautifully in circles on the floor. Have fun making the balloon spin. (See video below)
The air being forced out of the balloon through the straw is called Thrust.
By law of Science, the thrust should ideally push the balloon forward. However this air comes out with enough force to displace the mouth/nozzle of the balloon slightly to shift to the side, thereby pushing the balloon into a helical screw like motion, which appears to be circular due to the speed at which the balloon spins.
Gauri Parulkar is founder of Science Quotient, an activity lab where science is taught via fun and easy to learn experiments. She believes her effort of making science fun for children will help them develop a lifelong love for the subject. A strong advocate of STEM in education, she spends time gardening and drinking copious amounts of tea when she is not thinking of a new way of teaching kids about science.