Student Exploration: Measuring Motion
Vocabulary: distance, speed
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The speed of an animal is how fast it is moving. A speed of 6 m/s (meters per second) means that the animal moves a distance of 6 meters every second.
How would you measure the speed of an animal?
What do you think are the fastest animals?.
You have been sent on an African safari by International Geography magazine. Your assignment is to find the fastest land animals in the world. Your only tool is a video camera.
The safari is shown in the Measuring Motion Gizmo™.
On the SAFARI ADVENTUREtab, wait for an animal to pass by. Press the record button (). Press stop () when the animal has passed by.
Which animal did you record?
Was the animal walking or running?
Select the PLAYBACKtab. Practice using some of the different buttons on this tab:
Use the Play () button to replay the simulation.
Click Rewind () to go back to the beginning.
Click Advance frame () to move forward exactly one second at a time.
Click Tools at upper left, and drag some arrows () onto the recording to mark the positions of the animals at different times.
Use the Time slider to go to a specific time.
Get the Gizmo ready:
Question: How do you measure speed?
Run Gizmo: Record an animal running. Then switch to the PLAYBACKtab and watch your recording. Which animal did you record?
Measure: Click Rewind (). Use Advance frame () to advance the recording one second. Mark the animal’s position with an arrow () and repeat. Estimate the distance the animal traveled in one second. (Note: The trees in the background are 5 meters apart.)
About how far did the animal travel in 1 second? ____________________________
How did you make your estimate?.
Calculate: The distance an animal travels each second is its speed. What is the estimated speed of this animal? (Units are meters per second, or m/s.)
Measure: You can get a more accurate estimate of distance and time using these steps:
Use the Time slider to position the animal so that its nose is even with the first tree. Record the current time in the table below as Time 1.
Position the animal so that its nose is even with the last tree and record Time 2.
Subtract the first time from the second to get the Time difference.
Record the Distance from the first tree to the last. (The trees are 5 meters apart.)
Calculate: The speed of the animal is equal to the distance divided by the time difference.
What is the estimated speed of the animal now?
Is this value close to the speed you calculated before?