In this lesson students identify sources of heat around the home and in the environment. They learn and identify the terms ‘conduction’ and ‘convection’ as forms of heat transfer and identify everyday situations where these forms of heat transfer occur.
Review the concepts from Lesson 1 by asking students to explain the concept of heat transfer.
Introduce the students to the context for the lesson by reading/showing them Letter 2 from apprentice chef Pierre – sources of heat. Explain to the students that in order to assist Pierre in understanding heat, he needs to know about sources of heat and ways heat can be transferred from one object to another.
Ask students to think about familiar sources of heat around the home – heaters, appliances like hair dryers, and fires. Ask students to write a list of the items in their science journals. Have students share the items they identified.
Show students the images of different sources of heat around the home. Point out sources of heat that students may not have identified.
Ask students to list ways they think that heat is produced by these items. Students may nominate electricity (electrical energy) or burning (chemical energy).
BBQ with flames
Gas oven BBQ
Pot on stove
- Inform students that heat is transferred from object to object/place to place (system to system) in a variety of ways, and that they are going to explore two of these ways – conduction and convection – completing two activities that demonstrate each type of heat transfer.
- Heat transfer activities. Put students into groups of three (preferable).
- Conduction activity – Distribute to each group a stopwatch and one ice cube in a plastic resealable bag. Instruct students to hold the bag in their hands and measure the time it takes for the ice cube to melt. Students record their observations in their science journal as they work.
- Convection activity – Distribute to each group a coloured ice cube and a clear-plastic cup of warm water. Instruct students to place the ice cube in the water and to observe what happens to the colour from the melting ice cube in the warm water. Students record their observations in their science journal as they work. Have students share their observations with the class.
- Conduct a teacher-led discussion explaining the concepts covered during the activities. Ideas for this discussion can be found in Background information.
- Ask students to draw an example of heat transfer by conduction and convection in their science journals to demonstrate understanding. Then ask them to write a letter (collaboratively or individually) to Pierre suggesting the sources of heat he might find in his kitchen, along with an explanation of heat transfer for each source.
Students participate in the learning object How is the melting of ice affected by heat? to consolidate their understandings from the lesson.
Inform students that during the next lesson they will explore conductors and insulators.