Name: Date:
Student Exploration: Free-Fall Laboratory
Vocabulary: acceleration, air resistance, free fall, instantaneous velocity,
terminal velocity, velocity, vacuum
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Suppose you dropped a feather and a hammer at the same time. Which
object would hit the ground first? Hammer
2. Imagine repeating the experiment in an airless tube, or vacuum. Would
this change the result? If so, how? Yes, since there is no air resistance
in the vacuum, they would fall at the
same time.
Gizmo Warm-up
The Free-Fall Laboratory Gizmo™ allows you to measure the
motion of an object in free fall. On the CONTROLS pane
check that the Shuttlecock is selected, the Initial height is 3
meters, and the Atmosphere is Air.
1. Click Play ( ) to release the shuttlecock. How long
does it take to fall to the bottom? 0.90 s
2. Select the GRAPH tab. The box labeled h (m) should
be checked, displaying a graph of height vs. time.
What does this graph show?
Shows that the shuttlecock is accelerating downwards.
Page 1| 8
, 3. Turn on the v (m/s) box to see a graph of velocity vs.
time. Velocity is the speed and direction of the object.
Velocity is also referred to as instantaneous velocity.
Because the shuttlecock is falling downward, its
velocity is negative.
Does the velocity stay constant as the object drops? No
4. Turn on the a (m/s/s) box to see a graph of acceleration vs. time.
Acceleration is the rate at which the velocity changes over time. What
does this graph show?
Shows that the shuttlecock accelerates, then starts to steady its velocity
with a slight deceleration at the end.
Activity A:
Falling objects
Question: What factors affect how quickly an object falls?
1. Observe: Drop each item through Air from a height of 3 meters. Record
how long it takes to fall below. For the tennis ball, try to click Pause ( )
when it hits the ground.
Shuttlecock Cotton ball Tennis ball Rock Pebble
0.90 s 1.36 s 0.80 s 0.79 s 0.80 s
2. Form a hypothesis: Why do some objects fall faster than others?
Some objects fall faster that others because they have a larger
weight.
3. Predict: A vacuum has no air. How do you think the results will
change if the objects fall through a vacuum?
They will fall at the same velocity.
4. Experiment: On the Atmosphere menu, select None. Drop each item
again, and record the results below.
Page 2| 8
Student Exploration: Free-Fall Laboratory
Vocabulary: acceleration, air resistance, free fall, instantaneous velocity,
terminal velocity, velocity, vacuum
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Suppose you dropped a feather and a hammer at the same time. Which
object would hit the ground first? Hammer
2. Imagine repeating the experiment in an airless tube, or vacuum. Would
this change the result? If so, how? Yes, since there is no air resistance
in the vacuum, they would fall at the
same time.
Gizmo Warm-up
The Free-Fall Laboratory Gizmo™ allows you to measure the
motion of an object in free fall. On the CONTROLS pane
check that the Shuttlecock is selected, the Initial height is 3
meters, and the Atmosphere is Air.
1. Click Play ( ) to release the shuttlecock. How long
does it take to fall to the bottom? 0.90 s
2. Select the GRAPH tab. The box labeled h (m) should
be checked, displaying a graph of height vs. time.
What does this graph show?
Shows that the shuttlecock is accelerating downwards.
Page 1| 8
, 3. Turn on the v (m/s) box to see a graph of velocity vs.
time. Velocity is the speed and direction of the object.
Velocity is also referred to as instantaneous velocity.
Because the shuttlecock is falling downward, its
velocity is negative.
Does the velocity stay constant as the object drops? No
4. Turn on the a (m/s/s) box to see a graph of acceleration vs. time.
Acceleration is the rate at which the velocity changes over time. What
does this graph show?
Shows that the shuttlecock accelerates, then starts to steady its velocity
with a slight deceleration at the end.
Activity A:
Falling objects
Question: What factors affect how quickly an object falls?
1. Observe: Drop each item through Air from a height of 3 meters. Record
how long it takes to fall below. For the tennis ball, try to click Pause ( )
when it hits the ground.
Shuttlecock Cotton ball Tennis ball Rock Pebble
0.90 s 1.36 s 0.80 s 0.79 s 0.80 s
2. Form a hypothesis: Why do some objects fall faster than others?
Some objects fall faster that others because they have a larger
weight.
3. Predict: A vacuum has no air. How do you think the results will
change if the objects fall through a vacuum?
They will fall at the same velocity.
4. Experiment: On the Atmosphere menu, select None. Drop each item
again, and record the results below.
Page 2| 8
