What kind of material makes an object work well?
1. Ask the question
Students have been thinking about objects and the materials they are made of. Today’s question:
Some materials are better than others for a particular object; in fact some objects won’t work at all if they are made of the wrong materials. Provide an example:
- What are windowpanes usually made of?
(Glass, and possibly plastic) - What is it about glass and plastic that makes them good materials for windowpanes?
(Light can pass through them but they block the wind. They are transparent materials.) - Why not use wood for windowpanes? Wood is stronger and will not break as easily.
(Light can’t pass through wood.)
Have some fun with this discussion by encouraging some outlandish examples — e.g., a spoon can’t be made of butter because it would melt or get eaten. This will encourage flexible thinking and introduce a wider range of material properties, which will be useful in the next lesson.
To make a useful object, you have to choose your materials carefully. Today students will investigate some objects and think about what materials work well for them. They will also think about materials that would not work well for those objects.
Complete the first row of the classroom table using the windowpane example. Next hold up a plastic spoon and ask the students what to record in the table. Use the terms row and column as you refer to places in the table.
| Object | What it is made of | Other materials that might work well | Materials that would work badly |
|---|---|---|---|
| Window pane | Glass | Plastic | Wood |
| Spoon | Plastic | Metal, wood | Butter |
| (Student use) | |||
| (Student use) | |||
| (Student use) | |||
| (Student use) | |||
| (Student use) |
