Physical properties of materials

• Greet the learners.
• Tell the learners that we use different materials in life that are made up of matter.
• Ask them to name a few materials and say what can be made from it.

Possible answers [wool – jerseys; plastic – glasses; paper – envelopes; wood – furniture; leather – belts; etc.]

• Show them / let them show a few materials that they had brought from home.

• Show Video Clip 1: 3C Materials song. [2:25 min.] or Video Clip 2:  [1:55 min.].

• In this video the learners will be able to sing along, while different materials are shown. They will also see where it comes from and learn a few properties of the materials.

• Find out if they can identify the materials that were used to make their school uniform, the school building, their stationery, etc.
• Present an overview of physical properties of material by using Presentation 1: Physical properties of materials.
• Tell them that they must take note of the strength, flexibility, melting and boiling points of the various materials.

• Show Video Clip 3: Why have Valplast Flexible Denture? [2:25 min.] Or Show Video Clip 4:  Handmade Sunglasses // Proof Eyewear. [2:15 min.].

• Ask the learners who usually wear sunglasses:
  • Where do they buy it?
  • Do they think it can damage their eyesight?
  • Is it a fashion statement?
  • Is it prescribed sunglasses?
• Find out what the learners know about dentures [false teeth].

• The learners explain what they found interesting and what they did not know.
• They also share what they know and have learnt about dentures and sunglasses. Let them state whether they would think twice before they wear any type of sunglasses.
• Complete Worksheet A: Physical Properties of materials.
• Teacher to use Worksheet A: Memorandum to mark the learners’ work.

• Inform the learners that they must pay attention to the property details of the video that they will be watching.
• They can also write down important facts, which they can share at the end of the video clip.
• Show Video Clip 5: [7:15 min.].

• The learners share the important facts that they had jotted down.
• They can investigate and compare the strength of materials by completing
• Worksheet B: Investigate and compare the strength of material.
• The teacher monitors the groups while they are testing different materials’ strengths.
• The learners are also reminded to work as a group and record their findings.
• Teacher to use Worksheet B: Memorandum to mark the learners’ work.

• Ask one of the learners to make a cup of tea. He / she must explain the steps.  Listen carefully if they mention that the water must first boil.
• Now you can inform them about the boiling and melting points of a substance.
• Melting point:  temperature at which a substance starts to melt.

                         Water’s melting point is 0°C.

                         Candle wax melts at 50°C.

• Boiling point: temperature at which a substance starts to boil.

                       Water’s boiling point is 100°C.

                      Large bubbles rise to the surface of the liquid as it changes to the gas state.

• Show Video Clip 6: Boiling Points Demonstration. [4:00 min.].

• Investigation steps are revised.
• Learners will do an investigation to see what happens when water heats up and boils as set out in Worksheet D: Investigate what happens when water heats up and boils.
• Teacher to use Worksheet D: Memorandum to mark the learners’ work.
• This can serve as a formal assessment task. [Marks can be adapted accordingly]