How Efficient is an Immersion Heater

Prediction 1

I predict that as the wire gets longer the resistance will increase. This is because the electrons are being “pushed” around the circuit and they will collide with atoms in the resistor, as the atoms in the resistor are given more energy by the electrons they will vibrate faster and cause heat.

                           +---------------- Electrons are pushed this way (Figure 1)

 As the Electrons collide with the atoms they cause them to vibrate faster producing heat. So if the wire is longer the Electrons are more likely to collide with the atoms, and make the resistor hotter, thus the longer the wire the greater the resistance.

I predict that as I double the length of the wire the resistance will double. This is because the Wire is twice as long resulting in double the amount of collisions.

(Reference source Physics matters)

Prediction 2

I predict that as the Voltage increases the resistance will increase. This is because the electrons (see Fig 1) will be travelling faster and thus colliding more often and with greater energy with the atoms producing greater resistance.

I predict that as I double the voltage the resistance doubles. This is because Resistance= Voltage

                                                                                                                                                                         Amperes

And the larger the voltage the greater the resistance, so as I double the voltage the resistance will double as well.

R=V/A         R=4/2         R=2

R=V/A         R=8/2         R=4

Plan

Equipment                  

 Power Source

 Leads

 Voltmeter

 Ammeter

 Thermometer

 Stopwatch

 Measuring Cylinder

 Beaker

Method

 I will set up the equipment as shown in the diagram above. I will pour out 70ml of water into the measuring cylinder, I will measure to 1dp to insure a fair test. The water will then be poured into the beaker. I will then place the Immersion heater and the thermometer into the beaker. In the interests of reliable and accurate evidence I will be using the same equipment for all experiment’s. I will then switch the power pack on and start the stopwatch. I will be measuring the temperature every minute and check twice to make sure that the data is accurate. I will change the water every timeand make sure it is the same as the previous runs. I will change the variable factor every three runs of the experiment.

Results 1st variable

Length 20cm

Length 80cm

Length 30cm

Length 50cm

Conclusion