Build a Magnetic Car

Materials:
Pencil
Scissors
Tape
Two Bar Magnets
Straw
Small Box
Modeling Clay
2 Tooth Picks
A Quarter
A Sheet of Card StockStep One: Measure the length of the box using the straw. Cut the straw long enough to fit the length of the box. Tape the straw pieces to the bottom of the box.Step Two: Trace the quarter on the card stock using the pencil. Cut the circles out. Put the tooth picks through the straws with the ends sticking out. Place the circles on the end of the tooth picks. To keep the tooth picks on, roll a small ball of modeling clay and place on the end of the tooth picks.
Step three:
Put one of the magnets in the small box. Then place the lid on the box.
Step 4:
Take the other magnet and hold it in front of the box. The magnets will conduct and depending on the charge the car will either roll forwards or backwards.

Explanation: Each magnet has two poles. The poles are North and South poles. When the magnets are placed together, they either attract or repel. When the magnets are held with the North or South poles facing each other, they will repel. When the magnets are held with the North pole facing the South pole they will attract.
N<- ->N
S<- ->S
N-><-S S-><-N