How I Actually Used the Free Fall Tower Gizmo in Class
The Free Fall Tower Gizmo from ExploreLearning is one of those simulations that looks simple on the surface but catches students off guard if they don't know what they're doing. I've run this lab multiple times with different groups, and the gap between "I clicked around" and "I actually understand free fall physics" is wider than most teachers expect. Here's what happens when students open it. They see a tower, a platform, and two objects they can drop. The interface gives them controls to set height, mass, and whether to include air resistance. Easy enough. The exploration questions that follow are where things get messy.
Student Exploration Free Fall Tower Gizmo Answer Key
When I looked for a complete answer key online, I found scattered responses on random study sites, most of which were either incomplete or outright wrong on the analysis questions. The reason is straightforward: the Gizmo generates slightly different numerical results each time you run a trial, especially when air resistance is enabled, so a static answer key can't cover every permutation. What I ended up doing was building my own reference by running the simulation methodically and recording the patterns. The core relationships don't change even when the numbers do, and knowing those patterns lets you answer every question correctly without needing someone else's key. Start with the basic warm-up. Set both objects to zero mass and drop them from the same height with air resistance turned off. You'll notice they hit the ground at the same time regardless of shape or size. This isn't intuitive to a lot of students because everyday experience tells us heavier things should fall faster. The Gizmo data contradicts that, and the exploration questions push you to explain why.
The key insight most answer keys gloss over is that gravity accelerates all objects at the same rate in a vacuum, approximately 9.8 meters per second squared on Earth. Mass doesn't appear in the kinematic equation for distance under constant acceleration. The equation is d equals one-half times g times t squared. If you rearrange for time, mass cancels out entirely. That's why the two objects land together. When you turn air resistance on, everything changes. Now mass matters because the drag force depends on cross-sectional area and velocity, while gravitational force depends on mass. A heavier object of the same size will reach a higher terminal velocity and land first. I've seen students miss this distinction completely because the Gizmo doesn't explicitly label terminal velocity during the basic exploration. You have to infer it from the velocity-time graphs. One specific edge case tripped me up the first time I ran this lab. The Gizmo allows you to set the height of the tower, but if you set it below roughly 10 meters with air resistance enabled, the objects never reach terminal velocity during the drop. The velocity curve stays linear, and the simulation results look almost identical to the vacuum case. Students writing up their conclusions often report that air resistance had no effect, which is technically true for that height range but misses the pedagogical point. The workaround is to set the tower height to at least 50 meters when testing air resistance, which gives the objects enough time to diverge noticeably.
Get the Full Details
The analysis questions typically ask you to compare velocity-time and position-time graphs between trials. The velocity-time graph under gravity alone is a straight line with a negative slope equal to g. With air resistance, the slope becomes less steep over time as acceleration decreases toward zero. Recognizing this shape tells you everything you need to answer the graph interpretation questions without memorizing specific values. Another thing that catches people is the difference between the Gizmo's default Earth gravity setting and the option to switch to other planets. The Moon setting uses approximately 1.6 meters per second squared, which makes the fall noticeably slower and gives you a clean comparison trial. Running the same drop on Earth and Moon side by side is the fastest way to confirm the relationship between gravitational acceleration and fall time. If you're looking for a downloadable answer key, most sites offering one are either outdated or pulling from cached sessions that won't match your current Gizmo version. ExploreLearning itself doesn't publish official answer keys for student explorations, which is by design. The learning value is in working through the questions with the simulation data, not copying predetermined responses.
The practical approach is to run each configuration three times, record the average fall time, and compare across variables. This takes about twenty minutes total and gives you reliable data that matches whatever numbers the Gizmo generates for your specific session. The patterns hold: equal acceleration without air resistance, divergent acceleration with it, and a clear visual link between the graph shapes and the underlying physics.
