EXPERIMENT - Electric Jug
Aim: To determine how much electrical energy is changed into heat energy with a simple
electric jug circuit.
Diagram:
Power
supply
Thermome
ter
Wire
Beaker
Nichrome
wire
Ammeter
Voltmeter
Power supply
Wire
A
Resistor (nichrome wire)
Ammeter
Voltmeter
V
EXPERIMENT - Electric Jug
Method:
1. Set up the equipment as shown in the diagram
2. Pour 100mL of water into the beaker
3. Set the power pack to 6 volts (so that no more than 4 amps flows through the
ammeter otherwise the wires will melt)
4. Turn the power pack on, measure the voltage and current and then turn the power pack
off again.
5. Measure the temperature of the water to get a start value for the water.
6. Turn on the power pack and measure the temperature of the water every minute for 15
minutes.
7. Record your results in the table below
Results:
Variable
Value
Amount of water
100 mL
Voltage across nichrome wire
Current through wire
Time (minutes)
0
1
2
3
4
5
6
7
8
9
10
11
Temperature (˚C)
EXPERIMENT - Electric Jug
12
13
14
15
●
Graph the results from your table and put them in here.
Discussion:
1. Do the calculations below to work out how much energy came from the power pack and
how much energy got to the beaker of water.
This is the energy delivered by the power
pack
This is the energy absorbed by the water in
the beaker
Energy = Voltage x Current x Time (in
seconds)
Energy = mass of water x specific heat of
water x change in temperature
Energy = Voltage x Current x 15 x 60
Energy = 100 x 4.18 x (temp at 15 mins temp at 0 mins)
Energy =
Energy =
2. The two amounts of energy above should be the same but they are not (the energy
absorbed by the water in the beaker should be less than the energy delivered by the
power pack). Why is there a difference in the energy delivered by the power pack
and absorbed by the water?
3. What could be done to reduce the amount of energy lost in this experiment?
4. Using your graph, predict how long it would take for your jug of water to come to the boil.
Conclusion: