★Time : about 20 minutes (including setup and cleanup)
★Cost $: suppose to be $0, if every materials are in the home. (maybe you only have to buy insulationg rubber tape, and a balloon. about $1~2)
★Area of Science and Topic: General Science / Physics
★Learning objectives (what kids should learn as a result of performing this experiment): Students will learn how vibration can make sounds.
★Materials:
＊A plastic cup (better if transparent)
＊A long and thick paper roll (should be longer than the cup and strong enough endure the pressure of the stretched balloon, and it is easily found with cooking foils.)
＊Insulating rubber tape (to make the inner side of side of the cup vacuum)
＊A cutter and a pair of scissors (to make a whole and to cut)
*A balloon
★Procedure:
1. Make a hole on the bottom of the plastic cup. It should be as big as the size of the paper role.
2. Make one more hole on the upper part of the cup. This time the hole should be small. It should be small enough to be covered by mouth of anyone.
3. Put the paper role into the hole of the plastic cup. The paper role should be extended a little bit to out side of the mouth of the cup.
4. Make the paper role be fixed in the cup, and seal it with rubber tape. It should have no space of air to come out. 5. Stretch the balloon, and cut little of the narrow part. Stretch it again, and reach it on the mouth part of the cup.
6. Seal it with the rubber tape again. Make sure it is fully sealed and there is no air coming out of that part.
7. Finally, blow through the small hole on the upper part of the cup. It should make sounds.
★Tips for making the experiment work best with kids:
- Sealing might be difficult for the kids, but sealing will decide a great role, if the experiment is a successful experience, or it is not.
★Online resources for this experiment: Videos (links) Pictures (links) Websites (links)
http://blog.naver.com/chemijhy?Redirect=Log&logNo=100125945245
http://todaudrhkwkd.blog.me/140160435175
★How does this work?
When you blow into the small hole, there will be no way for the air to go out, thus the balloon increases as the air pressure increases. The air vibrates, and the balloon will also vibrate as the air is blown. The vibrating air passes through paper role, creates normal wave, and it makes sounds.
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