Design A: The cardboard parts were cut in different sizes before the tower was assembled.
AIC Kewdale • Year 7 Science
Gravity
Lift Tower
How can a falling weight make a string move? This project investigates the pull of gravity using a handmade cardboard tower, yarn, wooden sticks and rocks.
Created by Zunaira Zeeshan
Materials
Cardboard, brown paint, glue, hot glue gun, wooden skewers, white yarn, rocks, ruler, pencil and scissors.
Question
How does the mass of the rock weight affect the distance the yarn moves through the gravity tower?
Gravity connection
Gravity pulls objects towards Earth. The rocks have weight, so they are pulled down. Their movement pulls the yarn.
Prediction
If the rock weight has more mass, then the yarn will move further because a heavier mass has a greater weight force caused by gravity.
Design change: The final model used a strong vertical backboard and a box support at the bottom to keep the structure stable.
27 July 2026 - Cut: Cardboard pieces were measured and cut for the backboard, base and shelves.
27 July 2026 - Paint: The cut cardboard pieces were painted brown and left to dry.
27 July 2026 - Support: A small cardboard box was made to support the lower section.
27 July 2026 - Final assembly: The tower was completed with yarn, sticks and rock weights.
1
Build the frame
Glue the tall backboard to the base with hot glue. Add the shelf and lower support, then let the glue dry.
2
Add holes and sticks
Mark positions and carefully make holes. Put wooden sticks through the cardboard to guide the yarn.
3
Add yarn and rocks
Tie yarn around the rocks and thread it through the tower. Check that the yarn can move smoothly.
Safety: Use adult help for sharp tools and keep the model on a stable table when testing.
Variables
Independent: Mass of the rock weight (g)
Dependent: Distance the yarn moved (cm)
Controlled: Same tower, yarn, starting point and measuring method.
Weight force
The force due to gravity is F = m × g.
For a 100 g mass: 0.100 kg × 9.8 N/kg = 0.98 N.
More mass means a greater downward weight force.
Practice data for rehearsal only: These example values show how to calculate averages and draw a graph. Replace them with Zunaira’s measured results before submitting.
| Rock mass (g) | Trial 1 (cm) | Trial 2 (cm) | Trial 3 (cm) | Average (cm) |
|---|---|---|---|---|
| 100 | 7.2 | 7.4 | 7.3 | 7.3 |
| 200 | 14.8 | 15.0 | 14.9 | 14.9 |
| 300 | 22.1 | 22.4 | 22.2 | 22.2 |
| 400 | 29.5 | 29.8 | 29.7 | 29.7 |
Practice conclusion: In this example, increasing the rock mass increased the distance the yarn moved. This matches the idea that heavier masses have a greater weight force.
Claim
Gravity pulls the rock weight down, which makes the yarn move through the tower.
Evidence
The finished model has rocks tied to yarn at the top and yarn threaded between wooden sticks. When the rock weight moves downward, the yarn changes position.
Reasoning
Gravity pulls the rocks down because they have mass. The weight force can be written as F = m × g, where g ≈ 9.8 N/kg on Earth. As the rocks move down, they pull the yarn and transfer movement through the tower.
Reflection: I am proud that I created a working model using recycled cardboard. A challenge was making the tower straight and strong. Next time, I would measure more carefully and test more than one design before my final test.