infrared radiation practical

• Leslie Cube


  A device used to explore the principle of thermal energy and emission of infrared radiation.
• Leslie Cube


  a hollow, watertight cube typically made of metal with different surfaces on each side:

  • MATTE BLACK paint 
  • MATTE WHITE paint
  • Shiny silver
  • shiny black

  The varying surfaces allow us to investigate how different materials and textures emit infrared radiation differently.

  A) matt black

  B) matt white

  C) shiny silver

  D) shiny black

  
• • By using a Leslie cube we can understand how the surface material of an object affects the amount of INFRARED RADIATION it emits.
  • By comparing different surfaces, to learn which materials are good emitters of infrared radiation and which are not.
• In the Leslie Cube, you'll find more INFRARED RADIATION from:

  • the BLACK surface compared to the WHITE.
  •  MATTE surfaces than SHINY ones.

  This tells us that MATTE BLACK colours emit INFRARED RADIATION more than SHINY WHITE colours.
• 1. measurements can be taken at the same time.
  2. results will be more accurate.

  
• Investigating Infrared Radiation:

  • Place a LESLIE CUBE on a heatproof mat.
  • Boil water and fill the cube with the boiling water.
  • Allow the cube to warm up, then check that each side is at the same temperature with a THERMOMETER.
  • Position an INFRARED DETECTOR at a fixed distance from one face of the cube and record the INFRARED RADIATION it detects.
  • Do the same for each of the cube's faces, keeping the detector at the same distance each time.
  • REPEAT the experiment to ensure reliability.

  
• Leslie Cube




  A hollow, watertight cube made of metal with different finishes on each side such as:

  • MATTE BLACK paint 
  • MATTE WHITE paint
  • Shiny silver
  • shiny black

  The varying surfaces allow us to investigate how different materials and textures emit infrared radiation differently.

  
• Objects are constantly emitting and absorbing electromagnetic radiation with its surroundings & The balance of this will affect the object's temperature:


  • when absorbing radiation, the object gets warmer.
  • when emitting radiation, the object cools down.

  
• An object that's hotter than its surroundings:

  • More radiation will be emitted than absorbed.
  • It will lose energy and cool down.

  
• An object that's cooler than its surroundings:

  • less energy will be emitted and absorbed.
  • It will warm up.

  
• When an object absorbs and emits the same amount of energy:

  • The temperature stays the same.
  • It's gaining and losing the same amount of heat.

  
• Intensity:


  The power of radiation per unit area.

  • A measure of how much energy the radiation transfers to a given area in a certain amount of time.

  
• Graph of emitted radiation:


  Shows how much of each wavelength is emitted.
• • As the temp. of an object increases, the intensity of every emitted wavelength increases.
  • intensity of shorter wavelengths increase more than the longer wavelengths, which is why they seem to shift to the left

  
• The colour of Bunsen burner flames change as they get hotter:

  • Hotter the flame, the shorter the wavelengths of light emitted.
  • The colour changes from an orangey red to blue.

  Objects at room temp.:

  • The emitted radiation is all in the infrared range rather than visible light.
  • which is why we can't see the emitted radiation.

  
• The earth is constantly being bombarded by electromagnetic radiation from the sun and is emitting its own infrared radiation, as it's basically a big warm object.

  
• The earth has an atmosphere that can reflect absorb and emit radiation:


  During the day, more energy is being absorbed by the earth and atmosphere than is being emitted:

  • It increases the local temperature.

  whereas at night time less energy is absorbed than emitted:

  • The local temperature decreases.

  some part of the earth is always in the sun:

  • The overall temp. stays constant.