Required Practicals Flashcards
Resistance
1) set up a circuit with a battery , switch. Place your ammeter before the wire and the voltmeter in parallel to the wire.
2) using tape attach a wire to a meter ruler
3) use crocodile clips to attach the wire to the rest of the circuit. You can change the length of the wire by moving the crocodile clips further apart
Issues :
Zero error with a small resistance being recorded at start when it should be zero. This is caused by the crocodile clips not being exactly on zero at meter ruler. The contact between crocodile clips and the wire.
Heating effects :
If the temperature increases the resistance will also increase. To reduce use a low potential difference this will keep current low reducing any heating in wire. Only turn on current when taking a reading.
Specific heat capacity
1) Place a beaker on a balance and press zero
2) Now add the oil to the beaker and record the mass of the oil
3) Place a thermometer and immersion heater into the oil
4) Read the starting temperature of the oil
5) Wrap the beaker in insulating foam to reduce thermal energy transfer to the surroundings
6) Connect a joulemeter to the immersion heater ( the joulemeter tells us how many joules of electrical energy passes into the immersion heater )
7) Time for 30 minutes to
Allow the temperature to rise enough for an accurate read on the thermometer
8) read the number of joules of energy that passed into the immersion heater
9) Read final temperature of the oil
10) calculate the specific heat capacity
Thermal insulators
1) Place a small beaker inside a large beaker
2) Use a kettle to boil some water
3) Transfer 80cm*3 of the hot water into the small beaker
4) We then use a piece of cardboard as a lid for the large beaker
5) The lid must have a hole for a thermometer
6) Place a thermometer through the hole in the cardboard lid with the bulb end must being in the hot water
7) Record the starting temperature of the water and start the stopwatch
8) Record the temperature of the water every 3 minutes for 15 minutes
9) Repeat the experiment with the same volume of hot water however using a insulating material like bubble wrap to fill the gap between the two beakers. A range of insulating materials should be tested like cotton wall and polystyrene balls. The same mass of insulating materials should be used in each case.
Thermal insulators (thickness)
1) Start with a beaker fill with 80cm*3 of hot water and a thermometer in the water with the bulb end down.
2) Record the temperature of the water every 3 minutes for 15 minutes
3) Repeat the experiment however adding 2 layers of newspaper around the outside of the beaker
4) Repeat using 4 and 6 layers of newspaper
