Unit 8 Lesson 1 What Is Motion? Copyright © Houghton Mifflin Harcourt Publishing Company 1

Unit 8 Lesson 1 What Is Motion? Florida Benchmarks SC.4.P.12.1 Recognize that an object in motion always changes its position and may change its direction. SC.4.P.12.2 Investigate and describe that the speed of an object is determined by the distance it travels in a unit of time and that objects can move at different speeds. Copyright © Houghton Mifflin Harcourt Publishing Company 2

Unit 8 Lesson 1 What Is Motion? Twisting and Turning Position is the location of an object in relation to a nearby object or place. The second object or place is called a reference point. An object that moves has motion. Motion is a change in position. Copyright © Houghton Mifflin Harcourt Publishing Company 3

Unit 8 Lesson 1 What Is Motion? Where Is It? You know something is moving if its position changes in relation to the background, or frame of reference. Copyright © Houghton Mifflin Harcourt Publishing Company 4

Unit 8 Lesson 1 What Is Motion? Fast or Slow? Speed tells you how the position of an object changes during a certain amount of time. An example of speed is 2 m/sec. To find an object’s speed, divide the distance the object travels by the time it took to travel that distance. Copyright © Houghton Mifflin Harcourt Publishing Company 5

Unit 8 Lesson 1 What Is Motion? Fast or Slow? Velocity is the speed of an object in a particular direction. An example of velocity is 2 m/sec, east. Copyright © Houghton Mifflin Harcourt Publishing Company 6

Unit 8 Lesson 1 What Is Motion? Pushes and Pulls A push or pull is a force. A force can change an object’s speed or direction. Gravity is a force that pulls objects down to Earth. Friction is a force that acts directly against the direction of motion. Copyright © Houghton Mifflin Harcourt Publishing Company 7

Changing It Up Acceleration is any change in velocity. Unit 8 Lesson 1 What Is Motion? Changing It Up Acceleration is any change in velocity. An object accelerates if it speeds up, slows down, or changes direction. If a force pushing against an object in one direction is greater than a force pushing in the opposite direction, the object will accelerate. Copyright © Houghton Mifflin Harcourt Publishing Company 8