Specific Heat Capacity

Apparatus

• Immersion heater
• 13 volts on PSU
• 3 minutes on stop-watch
• Ammeter
• Voltmeter
• Leads
• Thermometer
• 1500g of water
• 5 beakers of different sizes measuring:  100g

                                                                       200g

                                                                       300g

                                                                       400g

                                                                       500g

Variables

• Amount of water (mass)
• Energy supplied (voltage × current × time)
• Energy loss
• Temperature of water before being heated

The variable that I will change is the mass of water as I think that measuring the

Temperature rise in different masses of water for a set period of time would produce the most accurate results. I also believe that it will give the best understanding of the whole experiment. I will be using five different masses of water which are 100g, 200g, 300g, 400g, 500g and I will be heating it up for 3 minuets. I will be doing a preliminary run, which will help me to determine which aspects of my experiment will need to be changed

Diagram

Method

1. Put on a pair of safety goggles, clear worktop of books and tie longhair back.
2. Get all the apparatus needed for the experiment.
3. Connect the PSU and set it up to 13 volts.
4. Add the ammeter and a 50-watt immersion heater in a series circuit with the power pack.
5. Add the voltmeter in a parallel circuit to the50-watt immersion heater.
6. Measure out the 5 different measurements of water into 5 different beakers. The variables of water needed to be measured out are: 100g, 200g, 300g, 400g and 500g.
7. Check the temperature of the water now and record it down.
8. Place the immersion heater into 100g of water and start the stopwatch for 3 minutes.
9. Record down the amp readings and the volt readings.
10. After 3 minutes, place the thermometer in the water and record down the temperature of the water.
11. Repeat experiment 4 more tomes increasing the water by 100g each time.

Risk Assessment

• Mind the water as it will be hot and you might burn yourself
• Mind the immersion heater as it might burn yourself
• Mind the water on the electric’s

Trial Results

3 minutes

Changes to plan

After looking at my preliminary results and having done the trial, I have decided to make a single change. From 3 minutes, I am going to let the experiment run for 5 minutes because it may be easier to get a final conclusion from the results. This is because the change in the temperature after 3 minutes is too close to the starting temperature. Therefore if I allow I to run for 5 minutes the results I collect will be easier to put in to a graph and so I will be able to produce a more accurate conclusion.

Results after making changes

After doing the experiment once, I decided to repeat the test another 2 times to get more accurate results. I then found out the average results from the 3 by adding them and dividing them by 3. Now I am going to put the average results onto a graph.

Graph

Conclusion

After observing the results on the table, I came to a conclusion that my results came out with a very good pattern. As you can see from this graph, my hypothesis was correct. I predicted that the that the bigger the mass of water, the lower the temperature will be at the end of the time period I heated it up for because the immersion heater is having to heat more molecules and the heat energy will be equally spread. I also noticed, from looking at this graph, that there is an even pattern. The larger the mass, the less the temperature increase. This is because there are much more particles and the voltage and current stays the same, which leaves the individual particles with less energy, as they have to share it with every particle in the matter. There were not any anomalous results, I reckon this is because the test was very accurate and there was a fair test made.

Evaluation

My method worked very effectively as it was very straightforward and I got very reliable results to enable me to evaluate my aim which was to find out what affects how quickly a substance such as water heats up. I followed my plan very well and my prediction came true, however, if I was to do it again, I would not change the mass but the voltage as I believe it would be interesting to see how it turns out. I also would use some sort of insulation as it would prevent heat loss and help the experiment to be much more accurate. If I was to re-do this experiment I would do it with solids not liquids as solids conduct heat much better then liquids do. I also think that it would produce much more accurate results. I believe that my experiment was a success but I should have used a digital thermometer. The only difficult part of this experiment was measuring out exactly the amount of water that I wanted because it will either be a tiny bit above or below. Overall I got reliable results and I fulfilled my criteria so I am happy with the results I got to prove them onto a graph.