Happy Sad Balls or Happy Unhappy Balls are one of our all-time favorites! Side by side, these two black rubber spheres look identical. But, when you throw them to the ground, one bounces wildly about the room (Happy Ball), while the other just lies there (Sad Ball), no matter how hard you throw it. What's the secret? That's up to your students to find out.
Easy to use and endlessly intriguing, our Happy Unhappy Balls are great for teaching discrepant event science, polymerization and the coefficients of friction and restitution. Each set comes complete with two balls approximately 1", information on their physical and chemical properties, plus a ton of fascinating experiments for you and your students to try.