ScienceGrade 3

Does Faster Mean More Energy? A Rolling-Ball Investigation

Energy of motion (kinetic energy): anything moving carries energy, and more speed means more energy.

Learning Objective

Students will learn that a moving object's energy of motion (kinetic energy) grows with the SQUARE of its speed — so doubling an object's speed gives it roughly four times the energy of motion, not just twice as much — and will see this demonstrated by comparing the size of a crater punched into clay by the same ball rolled at two different speeds.

What You'll Learn

Speed and energy are not proportional — energy grows with the SQUARE of speed, so 2x speed ≈ 4x energy.
A fair investigation changes only ONE variable at a time (here: speed, holding the ball/mass constant).
This same relationship is why higher vehicle speeds cause disproportionately more severe collisions.

Words to Know

Energy of Motion: The pushing power something has because it's moving; "A rolling bowling ball has energy of motion — that's why it can knock down heavy pins!"
Speed: How fast something is going; "A cheetah has way more speed than a turtle."
Investigation: A fair test where you only change ONE thing at a time to find the answer; "In our investigation, we only changed the ball's speed — everything else stayed exactly the same."
Crater: A dip or hole punched into something soft when it gets hit; "The fast ball punched a much deeper crater into the clay than the slow one."
Force: A push or a pull; "It took a big push — a force — to send the ball rocketing down the ramp."

Check What You Learned

Quick Quiz

1 / 4

If you roll the SAME ball twice as fast, how much MORE energy of motion does it have?

Fun Facts

A moving object's energy of motion (kinetic energy) grows with the SQUARE of its speed — doubling speed gives roughly FOUR times the energy of motion, not two times
Source: NASA Glenn Research Center, Beginner's Guide to Aeronautics, kinetic energy overview
This is one real reason speed limits exist: a car traveling 60 mph carries about four times the crash (kinetic) energy of one traveling 30 mph — not simply double
Source: National Highway Traffic Safety Administration, driver-safety materials on speed and kinetic energy
Kinetic energy depends on BOTH an object's mass and its speed (KE = ½ × mass × speed²) — holding the object (mass) constant and changing only the speed isolates speed as the one variable responsible for a change in energy
Source: NASA Glenn Research Center, kinetic energy overview

Lesson Info

Grade 3

2026-10-12

Standards Alignment

TEKS 3.7B
investigate how forces, including gravity, affect the motion of an object — this episode extends that into the energy of motion a moving object carries
4-PS3-1
use evidence to construct an explanation relating the speed of an object to the energy of that object — the same speed–energy relationship, at the adjacent grade band