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# Force and Motion

In Activity 1, the Big Ball Challenge guides students to make predictions, ask questions, gather evidence, and build on their understanding of motion. Round up as many different balls as you can find and head outdoors or to the gymnasium. Balls roll, stop, and change direction as students explore force and motion. In Activity 2, students go "on the move" as they explore different ways things move in the world around them. Using science notebooks is encouraged.

### Activity 1: Big Ball Challenge

Adapted from the Building Blocks of Science® Kindergarten unit, Push, Pull, Go

Activity objectives

1. Begin building an age-appropriate understanding of force and motion.
2. Observe, measure, and record the change in position of an object over time.
3. Explore the movement of a rolling ball and begin to build an understanding that motion is predicable; the ball travels in a straight line until a force stops it or changes its direction.

Teacher procedure

1. Head outdoors or to the gym with a variety of balls. Encourage students to roll the different sizes and colors of balls and make observations about how the balls move. Use some or all of the following questions to guide an active discussion about the balls and their motion:
• What starts the big ball moving? (A push)
• What stops the big ball?
• How is what stopped the ball a force?
• What can change the direction of the ball?
• How is what changed the direction of the ball a force?
• What is the same about the movement of the big ball and the small ball as we roll them back and forth?
• Do any of the balls take more force to move than another? How do you know?
• Do any of the balls take more force to stop? Change direction? (Reminder: A ball with more mass, more stuff in it, will take a greater force to move, stop, or change direction.)
2. Is there a slide on the playground? Ask students to make a prediction.
• What might happen if we put this ball at the top of the slide?
• What is needed for the ball to move?
• How might the ball move? What makes you think so?
3. Encourage students to try their ideas. Use a variety of balls.
4. Have students complete the following sentences. You may choose to have students do this as a class, and record their responses on a class chart, or to complete this individually, recording their own responses in their science notebooks.
• Today I found out ________________.
• Now I wonder ___________________.

### Activity 2: On the Move!

SCIENCE MAGNIFIER™, Primary (yellow dot)

Teacher background information

Force

A force is any push or pull. Students push a ball and the ball moves. The harder the push, the greater the move. The ball travels in a straight line unless another force causes it to stop or change direction.

Predictable patterns

With ample time to explore, students collect evidence to build the concept that the ball always rolls in a straight line until another force stops the ball or changes its direction. Student emphasis is on exploring, observing, and using a rich vocabulary to describe how objects move and the pushes and pulls (the forces) that move them.

Friction

Friction is the force of 2 objects rubbing together. A rolling ball is rubbing against the gym floor (or playground grass, pavement, etc.) and the floor is rubbing against the ball. The ball is rubbing against the air and the air is rubbing against the ball. Friction is the main force stopping the ball, but gravity plays a part, too.

Gravity

Gravity is the invisible force that pulls on objects on or near Earth's surface. Gravity pulls objects toward Earth's surface (the ground) unless something else gets in the way. For example, a student positions a ball at the top of a slide or ramp. When a force (a push) starts the ball rolling down the ramp, gravity will pull the ball to the ground (the floor) every single time unless something else stops it (e.g., a student reaches out and stops the ball before it hits the ground). At this grade level, students have an intuitive sense of gravity and how it affects the motion of objects.

Make the Connection: On the Move!