1R40.30 - Happy - Unhappy Balls
The happy - sad ball set has one ball that is much like a super ball and one ball that will absorb all of the energy and therefore will not bounce. The bouncing ball is made from polyneoprene and the non-bouncing ball is made from polynorbornene.
- Rod Cross, "Collision of a Happy Ball with a Sad Ball", TPT, Vol. 60, #1, Jan. 2022, p. 22.
- Kelley D. Sullivan, "What’s in a Name: Why Do We Call a Bouncy Ball Bouncy?", TPT, Vol. 57, #4, Apr. 2019, p. 229.
- David Kagan, "Happy Balls, Unhappy Balls, and Newton's Cradle", TPT, Vol. 48, #3, Mar. 2010, p. 152.
- Rod Cross, "The Coefficient of Restitution for Collisions of Happy Balls, Unhappy Balls, and Tennis Balls", AJP, Vol. 68, #11, Nov. 2000, p. 1025.
- Rod Cross, "The Bounce of a Ball", AJP, Vol. 67, #3, Mar. 1999, p. 222.
- Guenter Schwarz and Paul J. Haigh, "Demonstrating Elastic and Inelastic Collisions Using Bouncing and Nonbouncing Balls", AJP, Vol. 37, #3, Mar. 1969, p. 333.
- Bill Franklin, "Sad and Happy Balls", Teaching About Impulse and Momentum, p. 4.16.
- Jodi and Roy McCullough, "Energy with Happy and Sad Balls", The Role of Toys in Teaching Physics, p. 4.88.
- Pat Murphy, Ellen Macaulay, and the Staff of the Exploratorium, "That's the Way the Ball Bounces", Exploratopia, p. 138.
- Borislaw Bilash II, “Smart and Stupid Balls“, A Demo A Day – A Year of Physical Science Demonstrations, p. 204.
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