Gravity Demonstration Tower

Quick Answer: The Gravity Demonstration Tower is a clear-framed physics display for showing how gravity acts. As pictured, a plumb bob hangs on a thread to mark the true vertical, and a transparent drop tube lets students watch objects fall, supporting lessons on free fall, gravitational acceleration and air resistance.

What the Tower Shows About Gravity

The listing image of the gravity demonstration tower shows a two-level transparent frame held by corner connectors, a clear vertical tube and a pointed plumb bob hanging on a thread from the middle shelf. The plumb bob is the simplest gravity detector there is: whatever surface the tower stands on, the thread settles along the direction of gravity’s pull, which is why builders use a plumb line to check that walls are vertical.

The drop tube turns the display into a free-fall experiment. When air resistance is negligible, every object near Earth’s surface accelerates downward at about 9.8 metres per second squared whatever its mass, so two steel balls of different weight released together land together. Dropping a coin beside a flat piece of paper gives the opposite result, and crumpling the paper into a ball closes the gap, showing that air resistance, not mass, made the difference.

Older students can use the distance fallen and the time taken to estimate g from s = ½gt². Because the fall is short, hand timing with a stopwatch adds a large reaction-time error, so filming the drop with a phone camera at a high frame rate and counting frames gives better data. Timers, light gates and the objects to be dropped are not assumed to be included.

Specifications

Applications

• Showing that gravity acts vertically downward with a plumb line
• Comparing the fall of objects of different mass and shape
• Estimating g from drop height and fall time
• Discussing Galileo’s reasoning on falling bodies and air resistance

Care & Handling

• Place the tower on a level, stable surface and let the plumb bob come to rest before observations.
• Drop only small, smooth objects that pass freely through the tube, and cushion the landing point at the bottom.
• Clean the transparent panels with a damp soft cloth; solvents craze clear plastics.
• Check the corner connectors for tightness if the frame starts to wobble.

Why Choose LabEquip

Physics teachers usually buy this tower for demonstrations at the front of the class, where its clear frame lets everyone see the plumb line and the drop path. LabEquip lists it in the STEM kits range, and it complements the Newton’s Second Law Demonstration Apparatus when a unit moves from free fall to force and acceleration. Contact us through the contact page.

Frequently Asked Questions

Do heavy objects fall faster than light ones?

Not when air resistance is negligible. All objects accelerate at the same rate under gravity, about 9.8 metres per second squared near Earth’s surface. A heavy ball and a light ball of the same size dropped together land at almost the same moment.

Why does a sheet of paper fall more slowly than a coin?

The flat paper has a large surface area compared with its weight, so air resistance slows it a lot. Crumple the same paper into a tight ball and it falls almost as fast as the coin, showing that shape and air resistance, not mass, caused the difference.

What does the plumb bob show?

A plumb bob hanging freely lines up with the direction of gravity, pointing towards the centre of the Earth. The thread therefore marks the true vertical, a principle builders and surveyors still rely on.

How can students measure g with the tower?

Measure the drop height, time the fall and calculate g as twice the height divided by the time squared. Because the fall lasts only a fraction of a second, filming it in slow motion and counting frames gives a more reliable time than a hand-held stopwatch.

Would a feather and a hammer fall together in a vacuum?

Yes. Without air, everything falls at the same rate. Astronaut David Scott showed this on the Moon in 1971 during Apollo 15 by dropping a hammer and a feather, which landed together.

Which classes use the gravity tower?

It suits middle-school lessons on forces and gravity and senior classes studying free fall and the equations of motion. It is also a useful exhibit for science days, where visitors can try the coin and paper comparison themselves.

Last Updated: September 2026