Master of Karate

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What kind of experiment is this?

Experimental procedure and explanation:

• Tape a styrene foam board to a stick using scotch tape. Do not tape it too firmly. It should be weak enough to come off easily.
• Strike each board. The smaller board is hard to crack, but the larger board can be cracked very easily.
• When you strike a board, the surrounding air is accelerated with the board. Hence, you need enough force to accelerate the air mass as well as the board. The apparent mass of the board increases (added mass). As explained in “Large Balloon, Small Balloon,” the air mass is substantial enough to make a difference between the two.

[Keywords]	added mass, air mass
[Related items]	Added Mass, Large Balloon, Small Balloon
[Reference]	“The Wonders of Flow” Japan Society of Mechanical Engineering, Kodansha Blue Backs pp. 198-203