lemonade learning Insulation
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Conductivity

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Insulation and Conductivity

Baking Ice Cream Black and White Cool it, Melt it Heat Sinks Air and Water Comparing Heat and Electrical Conductivity

Although temperature and conductivity are a part of our everyday lives, many people still don't have a deep understanding about them. This video from Veritasium makes a good starting point for discussion of these concepts.

Black and White

Materials:
high gloss white paint
high gloss black paint
flat (matte) white paint
flat black paint
four sheets of cardboard or heavy bristol board (use the same material for each)
four thermometers
a sunny area that will not become shady over the coming hour or so

  1. Check the thermometers to ensure they read the same starting temperature.
  2. Paint each sheet with a different paint and let dry.
  3. Lay each sheet out in a sunny spot and place a thermometer in the centre of each.
  4. After about 30 minutes, read and record the temperature for each.
  5. Repeat again 30 minutes later.
  6. What did you find? Were the temperature readings different? If so, which were hottest and which were coolest? Why do you think that might be?

Cool It, Melt It

Materials:
2-3 ice cubes per each group, all of the same size
various materials that including insulators and conductors (pieces of various fabrics, aluminum foil, newspaper, string, tape, cardboard, etc.)
a thermometer for each group
a stopwatch

The first task is to compete with either the clock or other groups to try and melt your ice cube as fast as possible.

  1. Agree ahead of time on basic rules: you may not put the ice cube in your mouth, you can only use materials provided for melting, etc.
  2. Start the timer when all materials have been distributed.
  3. Each group is given an ice cube and access to the same various materials you provide.
  4. As soon as there is no solid matter left, you may record the time.
  5. What materials and techniques worked best to help melt the ice fastest?
  6. How will you use this to try and keep your next cube from melting?
  7. Materials through which temperature/energy moves easily (such as copper) are called conductors; those through which temperature/energy move slowly (such as styrofoam) are called insulators.
  Now, using only the materials provided, take your next cube out of the freezer and try and keep it from melting.
  1. Start the timer as soon as all ice cubes have been distributed.
  2. As soon as there is no solid matter left, the time should be recorded.
  3. How well did your predictions work? What would you change next time?
  4. Repeat again if desired. Did you improve your time?

Heat Sinks

No it doesn't! Heat rises! When we speak of a heat sink, we mean the ability of materials to absorb heat and slowly release it. An asphalt driveway is an example of a heat sink. It absorbs heat (just try walking barefoot on one on a hot summer day! The grass is much cooler). If you try walking barefoot on it an hour after sunset it will still feet comparatively warm. Materials:
a large bucket or aquarium filled with water
one or more of the following:
    - a similar sized container filled with sawdust, grass clippings, or any other plant matter
    - a 3rd container filled with sand or fine gravel
    - a 4th container filled with garden soil (note if it is mainly sandy, humus or clay or compare each)
    - a 5th container filled with rice or other grains
a thermometer for each container
a sunny area
a cooler area

  1. Start off with each container reading the same temperature. Record this temperature.
  2. Place all of the containers in a sunny area so that they each recieve equal sun exposure.
  3. Record the temperature of each an hour later.
  4. After two hours, record the temperatures, then move the containers to the cooler spot.
  5. Record the temperatures every 30 minutes for about 2 hours.
  6. What did you find? Were the temperature readings different? If so, which were hottest and which were coolest? Which materials let off heat the slowest? How can we use this to help conserve energy?

Air and Water

Materials:
a small tub of distilled water
a small tub of the same size and volume of salt water (1 teaspoon salt per cup of water)
several ice cubes of equal size & shape or sealed containers of equal size, shape & volume filled with hot water
three thermometers

  1. Check the thermometers to ensure they read the same starting temperature.
  2. Let the distilled and salt water tubs sit until they reach room temperature.
  3. Set one ice cube or hot water container in each of the tubs of water and the third on a plate beside the containers.
  4. Be sure that all the samples have equal sun, heat and wind exposure.
  5. Observe your samples
  6. Which one reaches room temperature fastest? Which is slowest? Which is the best insulator: air, salt water or distilled water?
  7. If you did this with ice, try repeating it with hot water or vice versa. Do your findings agree with your first attempt?

Comparing Heat and Electrical Conductivity

Materials:
a variety of different materials of the same size and shape such as:
copper
wool
wood
aluminum
ceramic
graphite
foam blocks, etc.
a low-voltage battery in a holder attached small circuit with attachable leads and a multimeter
several thermometers, temperature sensors or infrared thermometers
a heat source such as a hot plate
a small bowl of ice or ice water
a stopwatch or other reliable time-keeping device
paper and pencil to record observations

  1. Review the meanings of the words "insulator" and "conductor".
  2. Examine the materials and make predictions as to which will conduct heat and electricity the most efficiently, and which would make better insulators. You may wish to make a chart that includes predictions and places to record your actual observations.
  3. For each material, measure the initial temperature of the material. Place one end in the ice and measure the temperature at the opposite end. When the temperature falls by 5 degrees Celsius, record the time that took. For some materials, you may need to set a maximum time since they may not cool down this much in a reasonable timeframe.
  4. Let all the materials return to the ambient room temperature.
  5. Repeat the above, but this time place one end on the heat source and measure the temperature rise at the opposite end. Record the time it took to raise the temperature by 5 degrees Celsius. Again, you may need to set a maximum time for some materials.
  6. Let all materials return to room temperature.
  7. Now measure electrical conductivity. You will need to ensure safety measures are in place and everyone is aware of them since prolonged attachment of the more conductive materials to the closed circuit could lead to battery failure. overheating and possible fire and/or explosion.
  8. Attach the circuit so that it includes both the material and the multimeter in a closed loop. Quickly measure and record the resistance on the multimeter, then disconnect the circuit. Repeat for each material used.
  9. Compare your results for temperature and electrical conductivity. What do you notice? How does this compare with your earlier predictions?




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