Hooked on Science: Potato launcher

Ingredients

• 36-inch wooden dowel rod
• 24-inch copper tube
• Potato
• Ruler

Instructions

• STEP 1: Push one end of the copper tube into the potato. Pull the tube out of the potato.
• STEP 2: Push the other end of the copper tube into the potato. Pull the tube out of the potato.
• STEP 3: Use the wooden dowel rod to push one of the potato plugs about 6 inches into the copper tube.
• STEP 4: Push the dowel rod into the copper tube and observe. Using the ruler, determine how far the potato plug launched.
• STEP 5: Repeat steps 1 through 3. This time, using more force, push the dowel rod into the copper tube and observe. Using the ruler, determine how far the potato plug launched. Describe the effects of different directions of pushes and pulls on the motion of the potato plugs. Provide evidence that a pattern can be used to predict the future motion of the potato plugs.

Explanation

As you push the dowel rod into the copper tube, the volume of the trapped air decreases, while the pressure increases. This forces one of the potato plugs out of the tube, into the air.