Heat Flow Experiments

Question:

How does heat flow in solids?

Materials:

Conduction: Popping balloons to explain conduction.

Materials:

  • Bin
  • Candle
  • Lighter
  • Balloons
  • Thermometer
  • Water (hot, cold)
  • Aluminum foil
  • Soil
  • Corn syrup
  • Glue
  • Stop watch (phone)

Convection: Use of food coloring agents in water currents to explain convection.

Materials:

  • Thermocouples and readers
  • Tall beaker (1000 mL)
  • Conical flask (25 mL)
  • Food coloring agents
  • Ice cubes
  • Oil
  • Tongs

Radiation: Use of infrared cameras to study radiation

Materials:

  • IR camera
  • Glass plate
  • Styrofoam
  • Plastic cover
  • Glass slide
  • Metal piece
  • Laptop
  • Candle

Instructions:

Conduction:

  1. Inflate a balloon with air and ask the students what will happen if they bring the balloon near the candle. Also ask them to note down how long it takes for the balloon to pop.
  2. Now, ask the students to fill the balloon with ~10 mL of water (30 °C) and inflate with air. Ask them to hypothesize what will happen for this case?
  3. Discuss about good and bad conductors.
  4. Now repeat the experiment for different materials (cold water (30 °C), hot water (50 °C) aluminum foil, soil, corn syrup, glue)

Convection:

  1. Fill ¾th of the beaker with water at room temperature.
  2. Fill the conical flask with water and add ice. Mix well to get cold water and then add a food coloring agent
  3. Ask students to hypothesize what they will see if they place the flask in the beaker.
  4. Using tongs, carefully place the conical flask inside the beaker.
  5. Now ask the students to observe the convection current through color change.
  6. Discuss with the students about the density difference arising from temperature difference between water in the beaker and the conical flask.
  7. After some time, float an ice cube on water in the beaker and observe what happens.
  8. Repeat the experiment with water in conical flask at different temperatures (10 °C, 30 °C, 50 °C)
  9. Use a thermocouple to measure the temperature change with respect to beaker height.
  10. Repeat the experiment, except for this time, pour water from the conical flask into the beaker and observe the color change.

Radiation:

  1. Help students learn to use IR camera (focusing and taking pictures)
  2. Through IR camera, look at glass, Styrofoam and an object inside a plastic cover through IR camera. What do you observe? Talk about reflection, transmission and emission of thermal radiation.
  3. Cover a glass plate with the plastic cover in front of the IR camera. Position a candle behind the camera directly opposite to the glass plate. What do you see on the glass plate? This will help students understand that thermal radiation does not require medium to travel.
  4. Now ask the students to explore different objects with the camera
  5. Examples: Simultaneously eat glass and metal using a candle, Backside of a laptop during operation, Take selfies. Encourage them to take a cool picture, and we can project them at the end.