Lesson Overview

Students will explore how heat transfers between systems. Students will experiment with different materials to determine which one’s serve as conductors and which one’s serve as insulators. Students will then determine which insulators should be used to limit heat loss from homes and our bodies.

Target Grades: 6-8

Set Up Time: 30 minutes

Class Time: 2 hours

Lesson Resources

Objectives

  1. Explain how people use insulation.
  2. List the three kinds of heat transfer: conduction, convection, and radiation
  3. Describe which materials are the best conductors and insulators of heat.

Guiding question: What materials act as insulators and conductors of heat?

Educational Standards

ALASKA CULTURAL STANDARDS: B1, B3

ALASKA ENGLISH LANGUAGE ARTS:
Reading for Information Text: 6-8 RST.KI.3
Writing: 6-8 W.TT.2, 6-8 W.RW.10
Speaking and Listening: 6-8 SL.CC.1 (a,c)

ALASKA MATHEMATICS STANDARDS: 6.EE.9

ENERGY LITERACY CONCEPTS: 1.1, 1.2, 6.1, 6.2

NGSS: MS-PS3-4

Lesson preparation:
  • Read the Background section below.
  • Decide which version you want to do with the students: either comparing different types of cups (standard lab) or using one type of jar and testing different insulation materials (alternative lab). 
Gather Materials:
  • One insulation lab worksheet per student (standard or alternative – download from “Lesson Resources” above)
  • Pot/Kettle of hot water (NOT boiling for safety)
  • One tub filled with ice or snow per group of 3-4 students
  • One stop watch per group OR one class timer
  • Optional “Gear Up” activity materials per group: two pieces of ice or small snow balls; two rubber bands or O rings; Ice melting blocks or one metal item and one plastic item; infrared thermometer
  • Standard lab materials per group: 3-5 vessels made of different types of materials (paper cup, ceramic mug, mason jar, tin can, styrofoam cup, wooden cup, thermos, plastic cup); two plastic cups with some sort of insulation between them (fleece, newspaper, aluminum foil, fiberglass cloth/insulation, etc.)
  • Alternative lab materials per group: two jars of same size; insulation such as aluminum foil, plastic wrap and cotton balls; packing tape

Properly insulating our homes and buildings in Alaska reduces our energy use and keeps us warm. The parts of the house that separate the indoors from the outdoors and keep heat inside form the house’s “thermal envelope.” The thermal envelope includes the walls, floors, windows, and doors.

Heat is transferred through conduction, convection, and radiation through the thermal envelope. Conduction is heat transfer through solid materials and is slowed by insulation. Convection is heat transfer through gas or liquid. For example, when warm air comes out of a floor register in a forced air heating system, it rises. This rising of heat is called thermal buoyancy. As the air cools, it becomes denser and falls. This rising and falling movement is called a convection current. This explains why upstairs rooms are often warmer than downstairs rooms. Convection can be interrupted by a physical barrier such as a ceiling. In a typical house in a cold climate, plastic sheeting behind the drywall serves as an air barrier that stops heat losses through convection.

Radiation is heat transfer through electromagnetic waves. Radiant heat transfer doesn’t require contact between objects or the movement of fluid.  Instead, radiant heat energy is transported through empty space. Sunlight is radiated through space to our planet without the aid of fluids or solids. The heat energy from radiation can be interrupted by a material that reflects it, such as a window coating or aluminum foil. 

In order to reduce energy use and heating costs, a home’s thermal envelope must be able to control all three types of heat loss.

Conduction – The transfer of heat through solid objects that are in contact with each other. Heat travels through a solid material across a thermal gradient. Conduction is slowed by insulation.

Conductor – A material that transfers energy (such as heat) quickly.

Convection – The transfer of heat energy by the movement of a gas or liquid. 

Insulation – Material used to prevent or interrupt the transfer of energy (including heat, electricity, or sound).

Radiation – Heat transfer through electromagnetic waves. Radiant heat transfer doesn’t require contact between objects or the movement of fluid. Instead, radiant heat energy is transported through empty space. Sunlight is radiated through space to our planet without the aid of fluids or solids. The heat energy from radiation can be interrupted by a material that reflects it, such as the coating on a window or aluminum foil. 

Scientific Method (Scientific Process) – The methodological steps involved to pursue knowledge, which includes asking a question, conducting background research, creating a hypothesis, collecting data through observations and/or an experiment, analyzing the data, drawing a conclusion, and communicating the results.

Gear Up:
  • Discuss the importance of insulation in Alaska, especially during the winter.  We insulate our bodies by wearing warm clothing and snow gear to prevent body heat loss; insulating our houses with different materials is a similar concept.
  • Connect to local cultures and resources used for building, such as the traditional St. Lauwrence island home video linked in “Additional Resources” below

Optional “Ice melting block” mini lab (or demo):

  • Each lab station/group has two ice melting blocks, or one metal item (a conductor) and one plastic item (an insulator). Ask students to make observations about each one (without telling them what they are) and record on the worksheet. Students may notice that one “feels” colder.
  • Ask them to predict which one would melt an ice cube faster.
  • If available, use an Infrared thermometer to measure the blocks – they should be about the same temperature. Ask them if this changes their hypothesis.
  • Place an ice cube on each and have the students observe how quickly the ice melts on a conductor compared to an insulator. You can use a rubber band or o-ring to keep the ice cube in place.
  • Ask them to explain what happened, and guide them to understand how different materials transfer heat faster than others, which is why it is important to use good insulating materials for our houses to keep our heat in.
  • Explain how even though one ice block felt “colder” the items were the same temperature before ice was placed on them: the heat was transferring from our hand quicker than the plastic item which meant it felt cold. (BrainPop video on heat transfer).
  • After describing insulation (with physical examples or pictures if possible), ask what else can be done to save energy in a house. Examples might include shutting doors and windows, turning lights off, turning the heat down, or sealing cracks around windows and doors.
Activity:
  • Explain the concepts of conduction, convection, and radiation and write these definitions on the board. Provide examples of each form of thermal transfer. Discuss ways of insulating homes and buildings. Divide students into groups to perform the experiment.
  • Distribute the Insulation Lab worksheet to each student and explain each step of the experiment including: writing a hypothesis on which vessel will transfer heat fastest, setting up the experiment, conducting the experiment, and recording data and observations in lab notebooks.
  • Each student should be assigned a role: data recorder, thermometer reader, and time keeper. Have students practice reading the thermometer before they start. Decide the interval that the students will measure the temperature – 30 seconds, 1 minute, 3 minutes, etc.
  • Students can either test different types of vessels or you can choose one vessel (such as glass jelly jar or plastic cup) and each group can use a different insulation.
  • The Insulation Lab Alt worksheet is set up for this second type of experiment. After students have conducted their experiment, lead them through the graphing and interpretation steps. Students will then write a lab report to communicate their scientific process and results. 
Extension:
  • Have students research different insulation materials used in housing and write a report on how to properly insulate a house, discussing the pros and cons of different insulation materials. Ask students to think about traditional insulation materials used for housing. How did cultures thousands of years ago stay warm using local, natural materials?
  • Alternatively, ask students to consider the types of clothing we wear during different times of the year. Have students list the clothes they wear during the different seasons and the materials they are made of.
Evaluation:

Ask students to:

  • Turn in the completed Insulation Lab worksheet
  • Provide an example of and illustrate each type of thermal transfer (conduction, convection, and radiation)
  • Ask students to rank different materials and clothing as best to worst insulators.