Standard Grade Physics Practical Investigations

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Standard Grade PhysicsPractical Investigations
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You will be given a problem to investigate !
e.g. What effects the resistance of a wire?
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You can discuss the problem with others in the
class.
the length of a wire will effect the resistance
thickness of the wire
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• Having thought about the problem and talked about
  it with others in your class, write
  down the factor which you are going to
  investigate.

I am going to investigate the length of the wire.
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2. What is the aim of your investigation?
To find out how the length of a wire effects its
resistance.
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3. What is your hypothesis? (What do you
expect to happen?)
As the wire gets longer its resistance will get
smaller.
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4. Describe briefly how you are going to
carry out your investigation.
I will cut some wire into five different
lengths. I will measure the length and
resistance of each piece of wire.
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5. State clearly what variable you are going
to change.
I am going to change the length of the wire.
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6. What variables are you going to keep the
same?
I will use the same type of wire. I will use the
same thickness of wire.
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7. You should now carry out your investigation in
a safe way. Use the space below to note results
or for rough notes.

• 1.1 1 1.2
• 1.4 1.5 1.5
• 2.1 2 2.1
• 2.6 2.5 2.4
• 50 3.1 3 2.9

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8. Make a table of your results.
length resistance (W)
(cm) reading 1 reading 2 reading 3
average 10 1.1 1 1.2 1.1
20 1.4 1.5 1.5 1.5 30 2.1 2
2.1 2.1 40 2.6 2.5
2.4 2.5 50 3.1 3 2.9 3
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• On square ruled paper or graph paper draw a graph
  or a chart based on your results.

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10. What conclusion can you draw from your
results?
The longer the wire the greater the resistance.
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• What can you say about your hypothesis? (circle A
  or B or C below. If you circle B, complete the
  sentence.)
• A My hypothesis in part 3 is correct
• B My hypothesis in part 3 should be changed to
• C My results do not allow me to choose A or B

As the wire gets longer its resistance increases.
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12. Describe clearly how you set up and
carried out your investigation.
ohmmeter
wire
Using a ruler, I measured and cut five different
lengths of wire. Each length was connected to a
ohmmeter and its resistance was measured. I
repeated the measurement of resistance three
times for each length. I used the same type and
thickness of wire.