​The hot air mobile challenge asks kids to engineer a four wheeled mobile that can move from point A to point B with one simple breath of air. This STEM activity can be set up quickly with little to no cost.

Supplies

• wooden wheels (4 per team)
• Drinking straws
• Craft sticks
• Printer paper
• Tape
• Scissors
• Stapler
• Tissue Paper

How to build the Car

Use the straws to create an axle for the wheels; slide two life savers or wheels into each straw. Wrap tape around the ends of each straw so that the life savers cannot slip off.

Next, connect the two straws center to center using another straw or craft sticks. Then construct a sail and attach it to the base of the car.

How run a Hot Air Mobile Challenge

Before the activity starts use tape to mark off a starting line on the ground.  Then mark each foot beyond the starting line up to 6 feet. This will be the challenge course.

Give each team four wheels, set out the remaining materials on a communal table. You can get the wheels at any craft store. I found good deal on a set of 24 wheels on Amazon. Click here to see the current price. Show the kids your example car.  Tell them their first challenge is to create a car using the life savers and the supplies available.  Leave your car out as an example.

Depending on the age of the children you are working with they may need some help.  Try to be as hands off as possible, the objective of this activity is to get kids thinking and trying things on their own. 

After each team has successfully made a car that will roll, challenge them to build a car that will travel 1 foot with a simple breath of air.  Ask kids to think about sail boats, sail boats are powered by wind similar to their cars.  Encourage them to use their thoughts about sail boat in their car.

As children finish up, bring them to the starting line and have them give it a try.  If the car is successful, challenge them to move their car another foot.  If the car is unsuccessful, ask them to think about what changes can be made to improve their car, have them make those changes and come back and try it again. Repeat until each group has had a few chances to be successful.