Heating effects of a current

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Heating effects of a current

Aim- My aim is to see how the increase and decrease of the current effects the temperature of the water

Equipment List-    

  • Wires
  • Beaker
  • Water
  • Variable Resistor
  • Power Pack
  • Ammeter
  • Crocodile Clips
  • Thermometer
  • Goggles

Fair Test- I will use an equal quantity of water each time. I will make sure the equipment is working properly. I will start the experiment at the same temperature every time.

Pre Test- I am going to do a pre test to decide what voltage to use in the experiment. I will try 4 volts, 6 volts, 8 volts and 10 volts. The voltage was most effective at 10 volts because that’s were the temperature rose the most.

Method- I will gather the equipment on my list. Connect the equipment together making sure it is set up in parallel. I will fill the beaker with a 100ml of water and put the wire into it. I will then switch on the experiment. I will note down the starting temperature and the amp reading. I will then finish after 10 minutes, noting down the temperature. I will then figure out the temperature change. Then I will strengthen the variable resistor and do the procedure. I will do the experiment with the variable resistor at 5 different levels. I will then repeat this whole experiment again so I know my results are accurate.

Prediction- I predict that when the electric current runs through the wire, it will heat up. I think this because I know that the electrons will collide creating friction and therefore heat. The heat is then transferred through convection currents. Convection happens because the water that is heated becomes less dense, this is because the particles are moving a lot more. Then the water that is less dense spreads by making the rest of the water particles vibrate. I predict that the larger the current the larger the temperature will be. This is because as I said above the current will make the electrons collide, and the larger the current the faster they will move so the more they will collide so the larger the heat. I predict that the higher the resistant the more the temperature of the water will rise. This is because if the resistant is low the current will pass through the top part of the series circuit because it is a shorter distance round there and electricity always takes the shortest route. But if the resistance is high it will be easier for the current to go through the bottom part of the circuit because there is less resistance there. This will therefore mean that the wire will heat up because it will have more current running through it. If the wire heats up this will mean the water will heat up because it will conduct the heat from the wire. This is like a smaller version of an immersion heater. The wire in the experiment compares to the pipe, and when the pipe heats up the water around it heats up. I predict the graph will go toward upwards diagonally right because as the current rises so will the change in temperature.

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Average results


The evidence shows that as I predicted that the larger the current the more the temperature will rise. It also shows that the higher the resistance the more the temperature rose. I no this because the ammeter is set up in parallel to the resistor so if the current is higher on the ammeter then it must mean there is less current flowing through the resistor. This also means the current is flowing into the water.

My graph shows that the more the current increases the more ...

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