1. PowerPoint Slide show adapted from Mrs. Skinners Class PowerPoint Slide show adapted from Mrs. Skinners Class http://sciencewithskinner.com/index.htm http://sciencewithskinner.com/index.htm

2. Describing and Measuring Motion How do you recognize motion? An object is in motion when its distance from another object is changing An object is in motion when its distance from another object is changing

3. What is a reference point? An object is in motion if it changes position relative to a reference point An object is in motion if it changes position relative to a reference point

4. How do scientists calculate speed? Speed – the distance the object travels in one unit of time Speed – the distance the object travels in one unit of time Speed = distance Speed = distance time time

5. What is constant speed? If the speed of an object does not change, the object is traveling at a constant speed If the speed of an object does not change, the object is traveling at a constant speed

6. What is average speed? Most objects do not travel at constant speed To find average speed divide the total distance by the total time To find average speed divide the total distance by the total time Avgerage Speed = distance2-distance1 time2-time1 time2-time1

7. What is Velocity? Speed in a given direction Speed in a given direction When you know the speed and direction of an object’s motion, you know the velocity of the object When you know the speed and direction of an object’s motion, you know the velocity of the object Example 15 km/hour westward Example 15 km/hour westward

8. How do you graph motion? You can show the motion of an object on a line graph in which you plot distance against time You can show the motion of an object on a line graph in which you plot distance against time Time is along the x- axis and distance on the y-axis Time is along the x- axis and distance on the y-axis

9. How do you interpret motion graphs? A straight line indicates a constant speed A straight line indicates a constant speed The steepness depends on how quickly or slowly the object is moving The steepness depends on how quickly or slowly the object is moving The faster the motion the steeper the slope The faster the motion the steeper the slope

10. What is Acceleration? The rate at which velocity changes The rate at which velocity changes In science, acceleration refers to: In science, acceleration refers to: increasing speed increasing speed decreasing speed decreasing speed changing direction changing direction

11. How do you calculate acceleration? To determine the acceleration rate of an object, you must calculate the change in velocity during each unit of time To determine the acceleration rate of an object, you must calculate the change in velocity during each unit of time Acceleration = Final velocity – Initial velocity Acceleration = Final velocity – Initial velocity Time Time