Balancing a Hammer with a Ruler

A hammer can be balanced on the edge of a ruler (or even another hammer) using rubber bands. The system achieves stable equilibrium because the combined center of mass lies just below the fulcrum.

1. Wrap two rubber bands around the handle of a hammer near its head to form a loop.
2. Hook the loop around the end of a ruler.
3. Place the ruler so that its other end rests on the edge of a horizontal surface (like a table).
4. Let the hammer hang downward while the handle pushes upward on the ruler.
5. Observe how the hammer and ruler balance as a system.
6. For variation, replace the ruler with another hammer and repeat.

Incredible Gravity Tricks | Hammer Ruler and Balancing Forks - World of Engineering:

📄 The hammer-and-ruler trick - MEL Science: https://melscience.com/AU-en/articles/hammer-and-ruler-trick/?srsltid=AfmBOooeTEkXtFsKNOyfy3--lAVdjOcoQXUrqQA5ReM7kxyOoff1Yvy6

• Try using hammers of different sizes to see how the balance changes.
• Experiment with placing the rubber band loop at different points along the handle.
• Replace the hammer with another heavy object (e.g., wrench) to test the effect of shape and mass distribution.

• Ensure the hammer and ruler are securely placed to prevent falling.
• Perform the demonstration over a soft surface to avoid damage if it slips.
• Supervise younger children when handling heavy tools.

• Why does the hammer-and-ruler system balance? (Because the center of mass lies just below the support point, creating stable equilibrium.)
• What happens if the center of mass is above the fulcrum? (The system becomes unstable and topples.)
• Why does the structure oscillate when nudged? (Because small deviations shift the center of mass, and gravity restores it toward equilibrium.)