Just follow the step by step instructions and have fun by trying out by yourself!!
Things Required are:
2 toothpick
1 dc motor
1 9v battery
1 battery connector
1 on/off switch
4 bottle caps
1 big straw
1 gear
1 thumbpin with some hot glue
Step 1
Make a hole at the centre of each bottle cap using thumbpin
Step 2
Stick the gear to the toothpick using hot glue or strong liquid glue
Step 3
Cut an appropriate length of straw to hold the toothpick to rotate
Step 4
Stick bottle caps to toothpick using hot glue or strong liquid glue
Step 5
Make another arrangement without gear
Step 6
Stick motor upon the battery using hot glue
Step 7
Stick the battery motor arrangement to straw
Step 8
Stick the on/off switch
Step 9
Put the battery connector and make the connections.
Step 10
Stick the remaining wheel arrangement below the battery and you are ready to play with it.