6 . Cut the wooden dowel so you have two pieces that are both about two inches longer than the width of the chassis you have made . These will serve as your axles that rotate the wheels . Stick the dowels through the eye loops . Make sure that the axles are straight and that there is room for them to spin in the eye hooks .
7 . Cut holes a little bit smaller than the dowel through the center of each wheel , then attach the wheels to the base . Put the large wheels on the back of the car , opposite the snapper arm . Wrap a small rubber band around the axle on either side of each wheel so the wheels can ’ t fall off .
8 . Tie a string very tightly to the snapper arm on the mouse trap . The string should be long enough to just reach to the back axle .
9 . You may need someone to help you with this last step . Carefully pull back the snapper arm until it reaches the other end of the trap . Hold it in place while your helper wraps the string tightly around one side of the axle . Holding the string tightly , set the car on the ground and carefully let go of the trap - the string should be wound tight enough that it holds the trap in place . Next , make sure everyone ’ s hands are out of the way and then let go of the string . The trap will snap forward , propelling your car .
RESULT :
A set mousetrap is full of potential energy which , when released , is converted to kinetic ( motion ) energy . The design of your car allowed that energy to be transferred to the axle to make the wheels turn . When the trap snapped closed , it yanked the string forward . As the string was pulled , friction between it and the axle caused the axle to rotate , spinning the wheels and moving the car forward .
SCIENCE PROJECT
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SAFETY NOTE Mousetraps are dangerous ! If one snaps back on your hand it could break a finger . This project requires adult permission and supervision .
If you want to have the fastest car , here ’ s what you need to know and to do .
• Thicker axles increase speed .
• Try using different sized wheels in front or in back .
• Adjusting the length of the body and string alters the speed of the mousetrap car .
• Make it more durable by using lightweight wood such as balsa or basswood instead of cardboard .
• Use CDs or records as the wheels .
WINSPIRE : Empowering youth | February , 2017