Adding a propeller to a cart
Use scissors to trim the ends of the plastic propeller (approximately 1cm) so that the ends of the propeller won't hit the ground.
Press the propeller onto the shaft of the motor. The white dab of paint should face toward the motor.
Turn the propeller with your finger. Look at its shape. How can you tell which way the air will blow? Record your explanation in Notes on your handheld computer.
Now test your prediction. Choose the direction the propeller should turn to make the air blow away from the cart. While holding onto your cart, connect the battery wires to the motor. You can use the springiness of the wires to hold them lightly in place.
If the propeller doesn't blow away from the cart, reverse the wires.
Was your prediction correct? If not, write a better explanation. Write in Notes on your handheld computer.
While still holding onto your cart, carefully hold your other hand in front of and behind the propeller while it is on. Do you feel air moving in both locations or only in one? Is this the same as what you predicted? What is the difference you observe and why do you think it's that way? Record your answer in Notes on your handheld computer.
