Parents, Educators & Engineers

# Balloon Drive

English PDF (1.5MB)

Make a helium balloon hover in one spot, then move it through an obstacle course using air currents.

## MATERIALS

• 1 helium-filled Mylar® balloon
• Paper
• Paperclips of various sizes
• Clear tape
• Scissors
• Corrugated cardboard

## BRAINSTORM

1. How can you stop a balloon from floating upward?
2. How will you know when your balloon is neutrally buoyant?
3. Once your balloon hovers, how will you move it?

NOTE: Neutral buoyancy is when the force pulling down (gravity) is equal to the force floating up (lift), so the balloon doesn't move up or down.

## DESIGN AND BUILD

### Part 1: Make it hover

Balance lift and gravity. Add or subtract weights one at a time. Is it neutrally buoyant? When it floats in the same place for about five seconds, you've done it!

### Part 2: Explore air pressure — "drive your balloon"

Test it. Which moves the balloon best—one swift stroke right next to the balloon? Big swoops? Fanning? Quick swipes? HINT: When you sweep the cardboard beside the balloon, you temporarily remove some air. Other air nearby rushes in to fill the space, carrying the balloon with it.

### Part 3: Make it move!

Drive the balloon up and over or in between objects—chairs, a table, or a friend!

## INSIDE THE ENGINEERING

Balloons drift wherever the wind takes them. But if you add a way to control where the balloon goes, say by adding an engine, you've engineered a blimp—a balloon that you can fly wherever you want!