When Things Collide
Aligned to 4-PS3-3 — Next Generation Science Standards.
What this lesson teaches
Moving objects carry energy. When two objects crash into each other, energy passes between them, which can make objects speed up, slow down, or change direction.
Worked examples
Example 1
When a rolling marble hits a still marble, the first one stops and the second one shoots forward — the energy passed from one to the other.
Example 2
A bowling ball knocks the pins flying and barely slows down; a ping-pong ball bounces back and the pins stay put.
Example 3
Collisions make sound and heat too. Some of the energy leaves as the crack you hear, which is why the balls never bounce forever.
Practice questions
- Roll a marble into a line of still marbles. What happens to the marble at the end of the line?
- Predict what happens to a fast toy car when it crashes into a wall. Where does its energy go?
- Explain why a ball makes a louder sound when it hits the ground harder.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Cuando las cosas chocan
Los objetos en movimiento tienen energía. Cuando dos objetos chocan entre sí, la energía pasa de uno a otro, lo que puede hacer que aceleren, frenen o cambien de dirección.
Ejemplo 1: Cuando una canica que rueda golpea a una canica quieta, la primera se detiene y la segunda sale disparada hacia adelante — la energía pasó de una a la otra.
Ejemplo 2: Una bola de boliche manda a volar los pinos y casi no se frena; una pelota de ping-pong rebota y los pinos se quedan.
Ejemplo 3: Los choques también producen sonido y calor. Parte de la energía se va como el golpe que oyes, por eso las pelotas nunca rebotan para siempre.
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