Dollar Bill Inertia Challenge

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★★☆ Some safety precautions required to perform safely

Categories: Force, Motion

Alternative titles: Newton’s Bottle Trick

Summary

This demonstration uses a dollar bill, coins, and soda bottles to show Newton’s First Law of Motion. When the bill is quickly pulled away, the coins or bottle remain in place due to inertia, as long as friction is minimized.

Procedure

Place a dollar bill across the mouth of an empty soda bottle.
Stack several heavy, identical coins (such as six quarters) directly on top of the bill, centered over the bottle opening.
With a quick motion, karate-chop the bill out from under the coins without striking the coins or the bottle. The coins should remain on top of the bottle.
For a variation, place another bottle on top of the first one, mouth-to-mouth, with the bill between them. Snap the bill away quickly and watch as both bottles remain in place.

Links

The Bottle Inertia Challenge - Dollar Bill Snap - Sick Science!:

📄 Dollar Bill Inertia Challenge - Steve Spangler: https://stevespangler.com/experiments/dollar-bill-inertia-challenge/

Variations

Try different types or thicknesses of paper (e.g., cardstock vs. currency).
Test with objects of different masses (empty vs. full cans, lighter vs. heavier coins).
Experiment with different friction levels by using rougher paper, smoother bills, or lubricated surfaces.
Place the bill between other balanced objects and test inertia.

Safety Precautions

Practice with plastic bottles before trying glass to avoid breakage.
Be careful not to hit the coins or bottles directly—objects may fall and cause injury.
Avoid placing heavy objects where they could fall on feet or toes.
Supervise children attempting this trick.

Questions to Consider

Why do the coins (or bottles) remain in place when the bill is pulled away quickly? (Because of inertia—the objects resist changes to their state of rest.)
What role does friction play in this experiment? (Less friction between the bill and objects makes it easier for the bill to slide out without moving the objects.)
How would using sandpaper or sticky paper instead of a bill change the outcome? (Increased friction would pull the objects along, making the trick fail.)
How does this experiment illustrate Newton’s First Law of Motion? (Objects stay at rest until acted upon by a strong enough outside force.)