80
Lesson 80 of 84 · Forces
ExperimentBalanced and Unbalanced Forces (Part 3)
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
- potential
- work
- power
Materials Needed
- ruler
- cardboard
- marbles
- paper clips
Safety First
- Adult supervision recommended.
- Do not taste any materials.
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 3What do balanced forces result in?