---
title: "Speed and energy"
description: "Use evidence to construct an explanation relating the speed of an object to the energy of that object"
canonical: https://lightmysky.com/learn/science/speed-and-energy-mt_2Um22lTBZV
source: https://lightmysky.com/learn/science/speed-and-energy-mt_2Um22lTBZV.md
retrieved: 2026-10-19
---

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# Speed and energy

Use evidence to construct an explanation relating the speed of an object to the energy of that object

Subject: Science · Area: Energy · Ages 9 to 10
Page: https://lightmysky.com/learn/science/speed-and-energy-mt_2Um22lTBZV

## Ready when they can

- Explain that kinetic energy increases with speed at fixed mass, and that changing direction alone does not change kinetic energy when speed and mass stay the same
- Use observations from matched trials, such as greater target movement, as evidence about changes in kinetic energy
- Use the term 'kinetic energy' or 'energy of motion' appropriately

## Lesson: Speed and energy

Kinetic energy is energy of motion. An object at rest relative to the ground has no kinetic energy of motion relative to the ground. Mass is how much matter an object has. Using the same unchanged object keeps its mass the same.

For the same object, greater speed means more kinetic energy. Changing direction alone does not change kinetic energy if speed stays the same. Different masses also affect kinetic energy, so speed alone cannot rank objects with different masses.

After pushing a toy car, compare its observed speed. A harder push is not itself a speed measurement. If the same car moves faster after one push, it has more kinetic energy then. For a fair speed test, keep the target, surface and collision direction unchanged.

**Example.** Mia rolls the same ball at identical skittle setups. A slow roll knocks down one skittle; a faster roll knocks down five. A repeated pattern of greater effects supports greater kinetic energy at impact. Energy transferred from the ball can make the skittles move.

Matched dent tests use identical vehicles and identical panels hit in the same way. Repeated larger dents suggest more energy transferred at impact. Different panel materials can change the dents. Different surfaces can change how far a block travels. Subtract the shorter travel distance from the longer one to compare the movement.

Stopping time alone does not tell you kinetic energy. Stopping conditions can change that time. For the same object, compare its speed before stopping: the faster motion has more kinetic energy. Time over a whole ramp also does not establish speed at its bottom.

*(drawing: Keep car mass, block, surface and collision direction the same. Repeat trials to check the prediction.)*

**Recap.** For the same object, greater speed means more kinetic energy. Matched, repeated collision trials can provide evidence; different targets or surfaces can change the result.

## Practice

14 questions on this page, each with its working shown.

## Needs first

- [Naming types of energy](https://lightmysky.com/learn/science/naming-types-of-energy-mt_akBotspaf2)
- [Pushes & Pulls](https://lightmysky.com/learn/science/pushes-and-pulls-mt_B3W5EfimJw)

## Opens up

- [What happens when things collide](https://lightmysky.com/learn/science/what-happens-when-things-collide-mt_1MLi55bPnt)
- [Energy stores and transfers](https://lightmysky.com/learn/science/energy-stores-and-transfers-mt_Jvg_r4yWaY)