Learn on PengiAmplify Science (California) Grade 3Chapter 2: Why does the train rise without anything touching it?

Sesson 1: Contact vs. Non-Contact Forces

Key Idea.

Section 1

Touching and Non-Touching Forces

Key Idea

A force is a push or a pull. Some forces only work when objects are touching each other. These are called contact forces. For example, when a foot kicks a soccer ball, the foot must physically touch the ball to make it move.

However, other forces can work even when objects are not touching. These are called non-contact forces. They can act on an object from a distance.

Section 2

Magnets Push and Pull from a Distance

Key Idea

A magnet is a special object with an invisible force. Unlike a hand that must touch a door to push it, a magnet does not have to touch an object to move it. The force reaches across the empty space.

This magnetic force acts as a non-contact force. It can pull certain metal objects toward it, or it can push another magnet away, all without any physical contact.

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Chapter 2: Why does the train rise without anything touching it?

  1. Lesson 1Current

    Sesson 1: Contact vs. Non-Contact Forces

  2. Lesson 2

    Sesson 2: Magnetic Properties

Lesson overview

Expand to review the lesson summary and core properties.

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Section 1

Touching and Non-Touching Forces

Key Idea

A force is a push or a pull. Some forces only work when objects are touching each other. These are called contact forces. For example, when a foot kicks a soccer ball, the foot must physically touch the ball to make it move.

However, other forces can work even when objects are not touching. These are called non-contact forces. They can act on an object from a distance.

Section 2

Magnets Push and Pull from a Distance

Key Idea

A magnet is a special object with an invisible force. Unlike a hand that must touch a door to push it, a magnet does not have to touch an object to move it. The force reaches across the empty space.

This magnetic force acts as a non-contact force. It can pull certain metal objects toward it, or it can push another magnet away, all without any physical contact.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 2: Why does the train rise without anything touching it?

  1. Lesson 1Current

    Sesson 1: Contact vs. Non-Contact Forces

  2. Lesson 2

    Sesson 2: Magnetic Properties