• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Fire Alarm Investigation

Extracts from this document...

Introduction

Jahedur Rahman        10S        Fire Alarm Investigation

Fire Alarm Investigation

Aim:

In this investigation I will be making a fire alarm for an old person’s home. I will make a model then test it to see if it is suitable for an elderly home.

This investigation is mainly on finding a resistor which will turn on only in the case of a fire by a switch which will detect the fire early thus causing an evacuation of the home.

Plan

In my investigation I plan to use an electromagnetic bell which will ring only when the switch is activated by fire. My switch will be a negative thermal coefficient thermistor which has high resistance when the temperature is cold but low resistance when the temperature is hot, which will cause it to activate the electromagnet as this will complete the circuit. When the magnet is turned on it will pull on a disc of metal towards it connected to this disc is a hammer. When the magnet is turned on the hammer will be attracted and it will hit the bell.

...read more.

Middle

Risk Assessment

There are a lot of safety issues in this investigation. There is the risk of electrocution from the wires as at the end it is only live wire and if not use properly it may be fatal.

The power supply may also cause electrocution.

Also there may be electrocution from the cup of water as it will be used to cool down the thermistor as it is very sensitive but water conducts electricity so it will have to be handled with care.

I may get burnt by the Bunsen burner as it can get very hot and this can burn my skin.

As this is electricity I don’t know if the circuit may just blows, this is another factor.

As you see there are lots of safety issues to contemplate during the investigation.

Working On the Fire Alarm

  1. Firstly I started by making my circuit connecting the power supply with the thermistor leaving out the electromagnet.
  1. Then I made my electromagnet coiling around the iron core with wire. I then connected this onto the main circuit.
...read more.

Conclusion

My idea of the electromagnet did work and my prediction of how the circuit would work is correct.

Weaknesses in the investigation are that the thermistor being made of plastic melted when it was placed on the Bunsen burner. I will show how to improve this below.

I found that I had to make the position of everything had to be precise or the circuit would not work at all as there would be no flow of electrons due to breaks in the circuit.

Improvements

I stated above that the Bunsen burner melted the thermistor so I would cover this up with a shell which would not damage the thermistor but another question arises? Will the shell affect the temperature?

The thermistor is very sensitive. It started going of at room temperature but this is because its resistance is only 100 Ω (ohms) and so its temperature at which resistance will become low is about room temperature so I will use a thermistor which is at 10 000 Ω (ohms) which will only react to high temperatures around that of fires.

Science Coursework                Dr. Mazid

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Electrical & Thermal Physics essays

  1. Investigate how the temperature affects the resistance of a thermistor.

    This means that from a temperature of absolute zero, where the resistance should be infinite, to a temperature of about 150C the rate at which the resistance in the thermistor decreases very rapid whereas after this point the rate at which the resistance decreases is a lot slower and more constant.

  2. To investigate how the temperature affects the resistance of a thermistor.

    but I do not have enough evidence to support this statement. These properties in a thermistor make it very useful in industry for things such as machinery that can be damaged if it over heats. Putting a thermistor into a circuit such as that could mean that if the machine

  1. Experiments with a thermistor

    A more sensitive means of detecting changes in output should have been used, such as a Wheatstone bridge circuit, which is an accurate way of detecting and measuring small changes in electrical resistance, and is basically made up of two potentiometers connected in parallel with a galvanometer between them.

  2. The strength of an electromagnet.

    the current in the circuit Ammeter to measure current Coil of wire to make electromagnet Piece of iron and similar sized piece of steel to use as core 200g of panel pins on a paper towel for the magnet to pick up Balance calibrated in grams to weigh the panel

  1. Using an LDR to detect the intensity of plane polarised light allowed through a ...

    I was careful to stop this happening, however, by taking each reading in succession, then restarting, thereby taking the 0o reading both early, mid- and late afternoon to eliminate possible discrepancies, among other reasons. Random Variation What is random variation?

  2. Test whether changing a certain variable in an electromagnet circuit (either the coils around ...

    There could also be an alternative conclusion to line number three because we can see that from the start it continues in quite a steep upward gradient but then curves more and levels out until it is almost continuing horizontal.

  1. Investigating how temperature affects the resistance in a wire

    A 5% value is used in the x-axis error bars because it incorporates the notion that the inaccuracy goes up with a rise in temperature. Making the x-axis error bars bigger at higher temperatures and smaller at lower temperatures. There is also the possibility of inaccuracy among the ohms readings,

  2. A2 Viscosity investigation

    Once all the above steps are complete for syrup at room temp then do the above steps for the syrup at 30 and 40�C use the water bath to heat the syrup to these temperatures. The sensitivity of the measuring apparatus must be considered and the correct procedures to obtain the most accurate readings must be discussed.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work