Graphing Motion How Scientists Record and Plot Motion

Graphing Motion How Scientists Record and Plot Motion Data

Notes Write down the words in yellow. The words in white are discussion points, you may write these down, but are not required.

Important Vocabulary Data – pieces of information including words & numbers Data Table – a chart made up of columns and rows, used to organize data

Important Vocabulary Line Graph – graph that shows data as a line on a grid. Can show changes over time. X-axis – graphs horizontal line Y-axis – graphs vertical line

Distance-Time Graphs Scientists use line graphs to show the motion of an object. These line graphs are called distance-time graphs; they show the relationship between distance and time. X-axis = time an object travels Y-axis = distance an object travels

Types of Graphs Suppose a scientist measures how far a cheetah has run after a certain amount of time. The scientist records the data in the table below. Cheetah’s Motion Time (seconds) Distance (meters) 10 15 20 25 30 100 150 200 250 300

Types of Graphs The scientist makes a line graph to show the cheetah’s motion. Distance-Time Graph for Cheetah Distance (meters) 500 400 300 h a t e he 200 C 100 0 10 20 Time (seconds) 30

Constant Speed Graph Straight line – the speed did not change (remained constant for the time measured) Distance-Time Graph for Cheetah Distance (meters) 500 400 300 ah t e he 200 C 100 0 10 20 Time (seconds) 30

Distance (meters) 500 Constant Speed Graph Distance-Time Graph for Cheetah 400 300 To find the cheetah’s speed, divide the total distance by the total time. h a t ee h C 200 100 0 10 20 Time (seconds) 30 Speed = Distance/Time = 300 m/30 sec = 10 meters per sec The cheetah moved 10 meters during every second it was running.

Stopped Motion Graph A flat line on a d-t graph = shows an object has stopped moving. Distance-Time Graph for Cheetah Distance (meters) 500 400 300 200 h ta e e Ch 100 0 10 20 Time (seconds) 30 40

Stopped Motion Graph Distance (meters) 500 Distance-Time Graph for Cheetah Suppose after 30 sec the cheetah stops moving. After another 10 sec, at 40 sec, the distance traveled is 300 m. 400 300 200 h ta hee C 100 0 10 20 Time (seconds) 30 40 The graph shows that the cheetah had stopped moving.

Graphing Faster Motion A steeper line on a d-t graph = a faster, or greater, speed. Distance-Time Graph for Cheetah Distance (meters) 500 400 300 tah e e Ch 200 100 0 10 20 30 Time (seconds) 40 50

Graphing Faster Motion Distance (meters) 500 Distance-Time Graph for Cheetah 400 300 h ta ee Ch 200 100 0 10 20 30 Time (seconds) 40 50 Now suppose after 40 sec, the cheetah starts moving again. It travels 200 m in the next 10 sec. The new part of the graph is steeper. It shows that the cheetah moved 200 m in 10 seconds. The cheetah moved faster than it did for the first 30 sec.

Distance Cat Travels over Time 1. What does the x-axis show? 2. During which period of time did the cat stop moving? Ex: 0 -30 sec 3. During which period of time did the cat move faster? Ex: 0 -30 sec Distance (meters) Let’s Practice 100 90 80 70 60 50 40 30 20 10 0 20 40 60 80 100 Time (seconds)

Exit Ticket 1. What is speed? How is it calculated? Find the speed of this object: Distance: 525 cm, Time: 3 seconds 2. What does a flat, straight line on a Distance/Time graph mean?

Practice Motion Graphs information sheet and practice. http: //camillasenior. homestead. com/motion_graph s. pdf