Ben's Box of Blocks
Ben pulls his box of blocks across the rug. The pull meter says 2, but the box does not move.
Ben is pulling. Why does the box stay still?
Page 1
Science · Grade 3 Science
Chapter 1: Forces and Motion
A force you cannot see, doing something you can measure.
Ben pulls his box of blocks across the rug. The pull meter says 2, but the box does not move.
Ben is pulling. Why does the box stay still?
Make your guess to turn the page.
Still to come: 7 pages · Words to Know · What We Learned · 4 questions · Explain It in Writing · Ask and Wonder
The idea this lesson is working on — Children treat roughness as a quality that makes things slow, not as a push. The story makes the push visible: on the rug a pull of 2 moves nothing, so something is pushing back with at least 2. Ask: Ben is pulling, so why is the box still? A force has a size and a direction, and friction has both.
Friction is often wanted — Brakes, shoe soles, tires and gripping a pencil all depend on friction. It is not simply a nuisance to be reduced; much of the time it is the thing that makes something work.