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? I believe the hammer falls faster since it weighs more.
2. Imagine repeating the experiment in an airless tube, or vacuum. Would this change the
result? If so, how? The result would be different since there will be no air the feather won’t
glide; it will do a free fall. 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 DESCRIPTION tab, 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? 0.90s
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?
It shows that the shuttlecock is accelerating downwards.
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?
2019
, Get the Gizmo ready:
Activity A:
• Click Reset ( ).
Falling objects
• Select the DESCRIPTION tab.
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
0.71 0.79 0.80
2. Form a hypothesis: Why do some objects fall faster than others? Some objects fall faster
since they weight more.
3. Predict: A vacuum has no air. How do you think the results will change if the objects fall
through a vacuum?
Both items will fall at the same time.
4. Experiment: On the Atmosphere menu, select None. Drop each item again, and record the
results below.
Shuttlecock Cotton ball Tennis ball Rock Pebble
0.78 0.78 0.78 0.78 0.78
5. Analyze: What happened when objects fell through a vacuum? They all touched the bottom
at the same time.
6. Draw conclusions: Objects falling through air are slowed by the force of air resistance.
Which objects were slowed the most by air resistance? Why do you think this is so?
The shuttlecock and cotton ball were slowed the most by air resistance. This is due to
(Activity A continued on next page)
2019
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? I believe the hammer falls faster since it weighs more.
2. Imagine repeating the experiment in an airless tube, or vacuum. Would this change the
result? If so, how? The result would be different since there will be no air the feather won’t
glide; it will do a free fall. 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 DESCRIPTION tab, 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? 0.90s
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?
It shows that the shuttlecock is accelerating downwards.
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?
2019
, Get the Gizmo ready:
Activity A:
• Click Reset ( ).
Falling objects
• Select the DESCRIPTION tab.
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
0.71 0.79 0.80
2. Form a hypothesis: Why do some objects fall faster than others? Some objects fall faster
since they weight more.
3. Predict: A vacuum has no air. How do you think the results will change if the objects fall
through a vacuum?
Both items will fall at the same time.
4. Experiment: On the Atmosphere menu, select None. Drop each item again, and record the
results below.
Shuttlecock Cotton ball Tennis ball Rock Pebble
0.78 0.78 0.78 0.78 0.78
5. Analyze: What happened when objects fell through a vacuum? They all touched the bottom
at the same time.
6. Draw conclusions: Objects falling through air are slowed by the force of air resistance.
Which objects were slowed the most by air resistance? Why do you think this is so?
The shuttlecock and cotton ball were slowed the most by air resistance. This is due to
(Activity A continued on next page)
2019
