1. My hypothesis is that the resistance decreases as the temperature increases. I predict my results will have a negative correlation, and that as the temperature
2. http://www.gcsesciencemethods.co.uk/2014/05/thermistor-resistance-dependent-on.html http://www.nuffieldfoundation.org/practical-physics/effect-temperature-thermistor
The first method contained a risk assessment as well as a choice of two methods, one with a digital multimeter as well as one with a power supply and an ammeter. The second method has an explanation as to how a thermistor works, but I chose the first method because it had a multimeter method, which is easier than using a power supply and an ammeter, as it reads resistance directly in Ohms.
3. The equipment I will use is an NTC Thermistor, Hot Water (200ml), Cold Water (200ml), Beaker (500ml), Thermometer (0-100c), Digital Multimeter, and Connecting leads. You will need to boil water (at least 200ml) and put it in a beaker of at least 250ml, and then the same with normal water. You will then need to use connecting leads to connect the digital multimeter to the thermistor. You will need to turn the multimeter on, and set it to read Ohms, which is the unit for Resistance (Pd/current). You will then pour the hot water in the 500ml beaker, and immerse the thermistor into the 500ml beaker. You will then wait until the hot water reaches 70c, and then measure the resistance in Ohms. You will then repeat the experiment, to increase accuracy and to spot anomalies that might affect your final results. You will take a mean by adding up both results and dividing them by two.
My control variable is to immerse the thermistor until it reaches it’s maximum temperature, then wait for it to drop down to my desired temperature (70c), to prevent the temperature from rising after testing. I will also use the same thermistor as different thermistors will have a different internal resistance. I will try to close all windows, as wind of drafts...
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