Science Smarts: Scientific Stampede preview

By Patty Rooks on July 20, 2024.

I can hardly believe it is time for the Medicine Hat Exhibition and Stampede! If you have been putting off getting ready, I suggest that you get your boots and hats ready as it is next week already! At Praxis we are super excited to be part of the Methanex Kiddies Day’s in Pioneer Village once again.

All of my volunteers look forward to this event every year and this is no exception. We have all be pitching in getting activities ready for those young scientists that will be stopping by our booth. Just in case you cannot make it by, I thought I would share one of the activities we will have there.

*Remember to ask an adult before doing this experiment.

Materials

• cup (large plastic)

• string

• button

• small piece of sponge

• water

• ruler

• scissors

• nail

Procedure

1. Find the centre of the cup. Using the ruler, measure one centimetre from the left of centre and place a mark here. Measure one centimetre to the right of centre this time, and place a mark there.

2. To make the hole, BE CAREFUL, have an adult help you. You can do this by pushing a nail slowly into the cup until it punctures the cup all of the way through. Do this for the two holes you marked AWAY from centre.

3. Using the ruler, measure 50 cm of string and cut with the scissors.

4. Insert the end of the string into one of the holes in the top of the cup and pull it through the other hole.

5. Tie a knot in the string at the top of the cup. Hold the cup upside down, and the string should be dangling down.

6. Using the scissors carefully cut a small piece of sponge. About 2cmx2cm will be large enough.

7. Carefully poke a hole in the middle of the piece of sponge. Again, be careful you do not cut yourself.

8. Pull the string through this hole in the sponge.

9. Hold onto the string and sponge carefully and tie a button onto the end of this piece of string to keep it from pulling through the sponge. Make sure you have a good knot in the end to keep the sponge and button on the string.

10. Dip the sponge in a bit of water, and wring it out entirely. You just want it to be damp.

11. Pull the piece of sponge to the top of the string just below the mouth of the cup.

12. Wrap the wet sponge around the top of the string.

13. Squeeze the sponge against the string as you move the sponge down the string using jerky movements.

14. If you have time, you can decorate your “chicken” with the materials provided to make it look more life-like.

What is going on?

A sound should have been produced that made it sound like a clucking chicken. The water allows the sponge to move down the string, but there is enough friction to cause the string to vibrate, because the sponge skips and pulls at the string. The irregular touching on the string produces tiny taps that force the string’s molecules to move back and forth. The vibrating string strikes the molecules in the cup, and the cup’s molecules strike the air molecules causing them to move back and forth in rhythm with the cup and string. The sound is made louder because the inside of the cup acts like a megaphone that concentrates the sound waves and sends them out in one direction.

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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