K-5 friendly lesson
Try one idea, then jump into the activity.These lessons are designed to feel short, friendly, and easy to follow.
Muscles Work in Pairs
When one muscle pulls, its partner relaxes.
Lesson 3
Concept
Muscles move bones by pulling. Pairs like biceps and triceps work together: one contracts while the other relaxes.
Short Answer
Explain how biceps and triceps move your arm.