The immersion heater experiment
Aim – To see the effect of volume current on the effectiveness of an immersion heater heating 75 cm3 of water.
Current in circuit
Volume of liquid
Type of liquid
Amount of insulation
Size/shape of beaker
Size/shape of immersion heater
Time readings are taken over
Start temperature of liquid
Temperature change in 5 minutes
A small beaker was filled with 75cm3 of water at 24 degrees Celsius. A circuit was made that incorporated an immersion heater, an ammeter, a voltmeter, and a variable resistor.
The immersion heater was placed into the beaker of water and the current was set to maximum on the resistor. Two readings were taken for each set of results.
I predict that the current in the circuit will be proportional to the temperature change i.e. as the current is increased the temperature change will increase as well. This is because if the current increases there will therefore be more heat energy lost from the immersion heater.
Vol. Of H20
Temp. change 1
Temp. change 2
As I assumed my predictions have been proved correct. As the current increases, the temperature change in the water increases as well. This is because as more electrical energy flows through the circuit, the immersion heater produces more useful heat energy. This produces a convection current in the water and causes it to heat up. However, heat energy was lost in other places (parts of the immersion heater that were not in the water and the variable resistor were the main two places) and therefore the results could have been false. The insulation that we used would have helped a bit but did not stop some of the heat energy being lost.
To conclude, I would say that this experiment showed what it was meant to show. The current was directly proportional to the change in temperature i.e. as the current increased the change in temperature changed as well. However, many things still went wrong that could be corrected if the experiment was to be done again.
In my view, the experiment went well. It showed what it was meant to show. However, there were a few anomalies. For example, the temperature differed by more (10oC) when the current reading was 1.76A than when the current reading was 2.51A. This could be because the thermometer was not left for long enough to cool down. If we wanted to have a thermometer that was at the exact same temperature for each experiment then we could have used a new one each time. This may also be because the water started off at a different temperature. If I did the experiment again I would probably get my water from a container kept at constant temperature. I could also do the experiment again to see of the starting temperature of the water did affect the amount that the temperature changed in a certain amount of time.
Another thing that could have been done was to cover the container that we were doing the experiment in. There is no doubt in my mind that heat energy was lost from the top of the container. We could have used more of the insulating material on top of the beaker to prevent this. We also should have made sure that the heater was completely immersed in the water. If it was not in our experiment then the air surrounding the beaker would have been heated.
If we wanted to make sure that no heat was lost at all from our experiment then we would have to do the experiment in a vacuum. This is of course impossible in our case because we do not have the equipment to do this.
If I was to do the experiment again I would try to iron out all of the anomalies in my results by changing and adapting all of the things that affected my results this time round.