Puff Mobile

What you need:

• 3 non-bendable, plastic drinking straws
• 4 Lifesavers™ candies
• 1 piece of paper
• 2 paper clips
• tape
• scissors

Directions:

1. Make a car using only the materials on your list.  Here's the catch: to make your car move, you can only blow on it!
2. Test it out!  How far does your car go when you blow once?  How many puffs does it take to make the car travel 6 feet?

More:

Redesign your car so that it will travel the same distance with fewer puffs.  What happens if you change the size of the car?  What happens if you use fewer materials?  Or, what happens if you add a new material like thread spools?  Choose one thing to change (that’s the variable), and make a prediction.  Then test it!

Engineering Scoop:

When you blow, you create moving air, or wind.  When wind pushes against an object, it can make the object move. Think about a sailboat. Wind pushes against the sail and makes the boat move.  so a sail is one part of your car that can help it move.  Wheels can also help your car move.  Maybe you have a bike at home. What would happen if you took the wheels off and tried to move it?  (It takes a lot of force to move something that's rubbing along the ground.)  What other parts did you design to help your car move?

© 2001 WGBH Educational Foundation