Thermistors

You are to investigate a factor that may affect the resistance of a

thermistor

HypothesisRemember• A hypothesis is a

prediction• It should say how you

expect the DEPENDENT VARIABLE to change when you change the INDEPENDENT VARIABLE

• These variables need to be measured

The graph of resistance against temperature for an NTC thermistor looks like this:

The graph of resistance against temperature for an NTC thermistor looks like this:

Now write your hypothesis

Now write your hypothesis:

Planning

• You must research one method that will enable you to test your hypothesis

• You need to find at least two sources that have details about the same method

• You need to think about why one source is good and why the other source is not so good

Risk assessment

You must consider:• What are the hazards in your method that

may cause harm?• What is the harm that they may cause?• What will you do to reduce the risk of them

causing harm?

ContextTemperature control in a refrigerator

ContextTemperature control in a refrigerator

As part of your research, you need to find out how the results from your investigation could be used by a manufacturer of thermostats for refrigerators.

Range and interval

What values of range and

interval have you chosen?

Why have you chosen these values?

To get full marks for writing a method, you must include all the following:

• Most of the necessary equipment is stated.

• Most of the necessary equipment is stated.

• The method is written in an organised, logical sequence containing relevant specialist terms.

• Most of the necessary equipment is stated.

• The method is written in an organised, logical sequence containing relevant specialist terms.

• The measurements to be made or calculated are stated.

• Most of the necessary equipment is stated.

• The method is written in an organised, logical sequence containing relevant specialist terms.

• The measurements to be made or calculated are stated.

• Control variables are clearly identified, with details of how they will be controlled.

• Most of the necessary equipment is stated.

• The method is written in an organised, logical sequence containing relevant specialist terms.

• The measurements to be made or calculated are stated.

• Control variables are clearly identified, with details of how they will be controlled.

• Any significant hazards are identified, together with an assessment of risks and control measures.

• Most of the necessary equipment is stated.

• The method is written in an organised, logical sequence containing relevant specialist terms.

• The measurements to be made or calculated are stated.

• Control variables are clearly identified, with details of how they will be controlled.

• Any significant hazards are identified, together with an assessment of risks and control measures.

Choosing your equipment

What are the advantages and disadvantages of using each of these two to measure voltage?

If you had to measure a voltage in your investigation, which would you use and why?