Large Ball and Small Ball

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What kind of experiment is this?

Experimental procedure and explanation:

• You simultaneously drop a large ball and a small ball; both balls weigh the same. The small ball falls faster.
• In physics class, you learned that if we disregard air resistance, two objects fall at the same speed, regardless of their shapes and sizes. However, in real life, you probably experienced that the falling speed varies depending on size and shape. This is because air resistance acts as a brake.
• Air resistance depends on things like the shape and size of an object, and the speed with which it falls. Since the two balls have the same weight, the same gravitational force acts on both. However, the larger ball receives greater air resistance because the area at which air hits the ball (i.e., the frontal projected area; this is the area of an object when looked at from the front) is larger; therefore, its air resistance is larger. This force acts as a brake, and the larger ball falls slower.
• A parachute utilizes this principle. When you open a parachute, the frontal projected area becomes large (the shape also has an effect), increasing air resistance, so the fall becomes slower.

[Keywords]	Drag, Air resistance
[Related items]	Heavy Ball and Light Ball
[Reference]	“Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natsume Publishing, pp. 72–75.