Balanced and Unbalanced Forces

What You'll Learn

Balanced forces are equal in size and opposite in direction, so an object stays still or moves at constant speed. Unbalanced forces cause an object to accelerate or change direction.

Key Words

voltage
current
resistance

Materials Needed

rubber bands
blocks
spring scale
stopwatch

Safety First

Handle glass items carefully to avoid breakage.
Do not mix unknown chemicals together.
Tie back long hair before starting the experiment.

Steps

Step 1 — Read

Read the introduction and identify the main idea of this lesson.

Step 2 — Do

Test friction: pull a weighted box across 4 surfaces (carpet, tile, sandpaper, foil). Use a spring scale to measure the force needed for each.

Step 3 — Observe

Look for patterns in your observations.

Step 4 — Record

Make a graph or chart showing your results.

Check Your Understanding

Question 1

1 of 3

What do balanced forces result in?