# Physics coursework : temperature change of water heated with an immersion heater

Kate Robinson 11HC

## Physics coursework : temperature change of water heated with an immersion heater

Planning

I am going to investigate the temperature change of water heated with an immersion heater. The following variables are going to be kept constant throughout the investigation.

Amount of water in the beaker

Length of the coil

Room temperature

Voltage

The variable I am going to investigate is how long the heater will be heated for. I am going to record the temperature of the water every two minutes for twenty minutes. I am going to repeat this test three times so that I will be able to get an average reading and improve the reliability of my results.

To ensure that my investigation will be fair, I am going to use the same equipment throughout the experiment. I am going to keep all of the variables constant except time. I am going to keep the voltage and the current the same during the investigation. I am going to make sure that I use the same amount of water throughout the experiment.

To make sure my experiment will be accurate, I am going to use suitable equipment and carefully record my results in sensible units.

To carry out my investigation I need to prepare an immersion heater. To do this I am going to use some copper wire and wrap it around a glass rod. I am going to attach a crocodile clip to each end of the wire and attach this to wires that lead to the power pack. Before I begin to time my investigation I am going to make sure that the ammeter, volt metre and power pack are kept at a constant reading.

I am going to use the following equipment; power pack, thermometer, (so that I will be able to record the temperature) beaker, crocodile clips, volt metre and an ammeter (so that I can ensure that the voltage and current remain the same during the experiment), a measuring cylinder (to precisely measure the amount of water), stop clock (to time how long the heater has been heated for), glass rod with a coil wrapped around it which will be used as the heater.

I predict that the amount of time the heater is heated for will be proportional to the change in temperature.

I will be able to predict my results by using the following formula.

P = V x I

Where V is 2.75 and I is 3.4. I know this because I carried out a preliminary test.

P = 2.75 x 3.4

= 9.35W or 9.35 J/s

Therefore the energy in two minutes = 9.35 x 120

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