671 WordsMar 11, 20153 Pages
ISA CONTROLLED ASSESSMENT- Thermistors SECTION 2 ( Part 1 ) Answers 1. Yes the results support my hypothesis, which was, as the temperature increases the resistances decreases. For example the resistance at 20OC was ______ and at 50OC it was ______ which was much lower. Also the graph shows a negative correlation with a curve of best fit. This shows the relationship is not Ohmic as it is not a straight line. 2. EITHER; Yes I had an anomalous result, it was at a temperature of __OC. It was higher/lower (select the correct one) than it should have been. If the resistance at this temperature had been on my line of best fit the value should have been _____ Ohms(read this off your graph). No I did not have any anomalous results. I know…show more content…
THERE ARE NO OTHER CORRECT ANSWERS 6. The smallest interval was 10OC, i.e. the difference between 20OC and 30OC. Yes this was a suitable interval because by moving from 20OC to 30OC there was a difference in the resistance of _____ Ohms. It was also possible to see a pattern in the results using intervals of 10OC. However to create a more accurate line of best fit I could have used intervals of 5OC. If I had the resistance value of 15OC would have been ______ Ohms (read this off your graph). CIRCLE the anomalous results in BOTH the table of results and graph if you have any. Make sure you say; a. Whether each result is a higher or lower value than it should be. b. What could have caused it, the best answers for this are; i. If it was too high, the thermistor was not given time to warm to the temperature of the water bath and therefore was taking a reading at a lower temperature. ii. If it was too low the temperature must have been higher than thought. The way this could have happened is if the thermistor was held close to the heating element in the water bath and been in a hot spot. 7. The results could be useful because in the context a company is always making a product which will turn something on (a thermostat in a house central heating system, fire alarm in a room which has got hot) or off (a kettle when the water is at 100OC). The manufacture needs to know the resistance at the temperatures which are important for these functions, so that they can


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