A Jumping Toy

Materials you need : 2 pieces of thick cardboard (about 4 cm x 6 cm) (or two phonecards) Rubber bands Masking tape Scissors Metre rule (or measuring tape)

Let’s make a jumping toy!

Procedure :

1. Making the toy

 (a) Cut out two slits near the edge of each piece of cardboard.

(b) Join the two pieces of cardboard together using masking tape.

(c) Tie a rubber band over the toy as shown below.

(d) Spread out the toy flat on a table and let it go. Watch it jump!

2. You are to increase the number of rubber bands used in your toy and record the height at which the toy jump for each rubber band.

(a) What is the aim of your experiment?

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(b) Which of the following variable(s) should you keep the same and which variable(s) should you change? Tick ( P ) the correct boxes in the table below.

Variables	Keep the same ( P )	Change ( P )
Thickness of cardboard (card)
Number of rubber band
Size of rubber band
Size of cardboard

(c) Where did the toy obtain the energy to jump?

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(d) Record your results in the table below.

Number of rubber bands	Height at which the toy jumped
	1st try	2nd try	3rd try	Average
1
2
3

(e) How does repeating the experiment make the results more accurate?

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(f) What is the relationship between the number of rubber bands used and the height at which the toy jumped?

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(g) Conclusion : How did the toy work? Fill in the blanks with the correct words given below. You may use each word more than once.

When the toy was spread out, the _________________________ rubber band had more ____________________________________. When the toy was let go, the rubber band which is ________________, returned to its original length, making the toy ____________. This is because the _____________________________  in the rubber band had changed to ____________________________.

elastic

jump

kinetic energy

stretched

elastic potential energy

 

(of the stretched rubber band)

(h) Write down the main energy change in this experiment.