Random error Essay
The fixed resistance that gives me the greatest range of results is 1000 ?. Interestingly this happens to be the same resistance as the resistance of the thermistor at 25 i?? C Response time The response time of my sensor depends upon how quickly the thermistor reacts to a change in the temperature of the surrounding environment. The response time of my sensor does not need to be particularly fast under or around ten seconds would be sufficient. This is mainly because the plants in the greenhouse will not be affected be a short period of time at a slightly cooler temperature than the optimum growing temperature of 25 i??
C. The thermistor that I am using will be able to detect the temperature in one second or less, a period of time that will not affect the plants. Random error There is a chance that a random error could occur in my sensor. This however is a small chance, mainly due to the fact that the sensor will be working permanently, rather than taking results every hour for example. Systematic errors There is a possibility that a systematic error could occur in my sensor, these are mainly down to instances such as zero errors, and usually all of the results are affected.
In my sensor, temperature could change the resistance of the fixed resistor in the potential divider. I do not think this should be a problem in my sensor though because the sensor will not become hot enough for this to be a factor. Now that I have taken these things into consideration I am going to perform an experiment to find out what the output potential difference will give at certain temperatures. I will place the thermistor inside a small coin bag, so that I can put the thermistor into a beaker of water.
Due to water having a high specific heat capacity, it cools down quite slowly. As a result of this, I will put my thermistor in the bag into a beaker of water. I will read the potential difference across the thermistor at different temperatures of water, starting at 50i?? C letting the water cool and taking readings every 5i?? C. When the water temperature reaches about room temperature, I will put some ice cubes into the beaker of water to lower the temperature of the water further. The potential difference output from the lab pack transformer will be 10v.
University/College: University of Arkansas System
Type of paper: Thesis/Dissertation Chapter
Date: 6 July 2017