Infrared absorption and emission

• What is the main focus of the practical described by Mr. Reese?

  Infrared absorption and emission
• What is the purpose of the Leslie cube in the experiment?

  To test infrared radiation emission from surfaces
• What surfaces are compared in the Leslie cube experiment?

  Matte black and shiny surfaces
• Why is the cap placed on the Leslie cube?

  To reduce heat loss to convection
• How does heat loss occur in the Leslie cube experiment?

  Through conduction into the table
• What is the distance maintained for the infrared thermometer during the experiment?

  10 centimeters
• What temperature was recorded for the shiny side of the Leslie cube?

  35.1 degrees Celsius
• What temperature was recorded for the matte black side of the Leslie cube?

  83.8 degrees Celsius
• What conclusion can be drawn about matte black surfaces from the experiment?

  They emit more infrared radiation than shiny surfaces
• What experiments can be conducted to test absorption of different surfaces?

  • Use copper tubes covered in different materials
  • Measure temperature inside tubes exposed to infrared lamp
  • Use boiling tubes with different surfaces and record temperatures
• What materials are used to cover the copper tubes in the absorption experiment?

  Shiny, matte white, and matte black materials
• Why should cotton wool be used around the thermometer in the copper tubes?

  To prevent the thermometer from touching the sides
• What happens to the temperature of boiling tubes filled with water when exposed to infrared radiation?

  Their temperature increases
• What is the relationship between surface type and infrared radiation absorption?

  Matte black surfaces are best absorbers
• What is the expected temperature outcome for matte black surfaces after exposure to infrared radiation?

  They should have the highest temperature
• How do shiny surfaces perform in terms of infrared emission and absorption?


  They are poor emitters and absorbers
• Why is a white t-shirt preferable on a sunny day compared to a black t-shirt?

  It absorbs less infrared radiation
• What are the properties of different surfaces regarding infrared radiation?

  • Matte black: best emitter and absorber
  • Shiny: poor emitter and absorber
  • Matte white: intermediate emitter and absorber