investigating thermal conductivity

• dark ,matt surface are good

  emitters and absorbers
• light, shiny surfaces are poor

  absorbers and emitter of infrared radiation
• in this practical you should

  • make and record measurements of temperature and time accurately
  • measure and observe the effect of different materials as thermal insulators
  • use appropriate apparatus and methods to measure the effectiveness of different materials as thermal insulators

  
• the aim of this experiment is to

   compare the effectiveness of different materials as thermal insulators.

  A) small beaker

  B) large beaker

  C) cardboard

  D) stopwatch

  E) thermometer

  
• Method

  1. Place a small beaker into a larger beaker

  2. Fill the small beaker with hot water from a kettle

  3. Put a piece of cardboard over the beakers as a lid. The lid should have a hole suitable for a thermometer

  4. Place a thermometer into the smaller beaker through the hole

  5. Record the temperature of the water in the small beaker and start the stopwatch

  6. Record the temperature of the water every 2 minutes for 20 minutes

  7. Repeat steps 1-6, each time packing the space between the large beaker and small beaker with the chosen insulating material
• Plot a graph of temperature (y-axis) against time (x-axis)
• Plot all of the curves on the same axes. This will make the materials

  easier to compare.

  
• • The curve which takes the longest time for the water temperature to drop (the shallowest)

  should be the material which is the best insulator.

  
• The temperature falls quickly at high temperatures and slowly at low temperatures.

  
• • When the beaker is at a high temperature, there is a big difference between the temperature of the beaker and the temperature of the surrounding air.


  there is a high rate of transfer

  
• • When the beaker is at a lower temperature, there is less difference between the temperature of the beaker and the temperature of the surrounding air. 


  This means there is a lower rate of transfer.

  
• do not overfill the kettle to prevent

  burnt skin form boiling water
• to prevent scald skin from knocking off the beaker it is advisable to

  Place the beaker away from the edge of desk.

  Carry out the experiment whilst standing.