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# Aerial balancing toy

## Experimental procedure and explanation:

• Cut the top of a polystyrene foam hemisphere to create a hole in the center. Eight legs (bamboo, etc.) are attached around it, and polystyrene balls (40 mm in diameter in this experiment) that serve as weights are attached to the tips.
• If you blow the air from below with a dryer, the aerial balancing toy will float.
• There are weights around it for good balance. The longer your legs are, the easier it will be to stabilize, but be aware that if you make the weight too heavy, it will not float.
• When the wind from the dryer deviates from the center of the balancing toy (deviating to the left in the explanatory figure), the flow flows to the right, and the recoil (reaction) exerts a leftward force on the hemisphere. As a result, the balancing toy will move toward the center of the dryer wind (to the left). When the flow hits an object and bends, the object moves in the opposite direction. This is the same as the movement of the square in "circle and square".
• When the dryer wind deviates from the center of the dryer (the explanation drawing is shifted to the left), the flow flows out to the right, and a left-facing force is applied to the hemisphere because of the reaction. As a result, the ladder moves toward the center of the dryer's wind (to the left). When the flow bends against an object, the object moves in its opposite direction. This is the same as the movement of the "round and square" squares.
• The balancing toy floats in the air because of air resistance.
• Be careful not to make the whole structure too heavy.
 [Keywords] Momentum theory, air resistance [Related items] Circle and Square 1, Circle and Square 3 [Reference] “The Wonders of Flow,” Japan Society of Mechanical Engineering, Kodansha Blue Backs, P140-143
Last Update：3.3.2017