You will now create an outline for your final assignment.
In this lesson you learned about how different materials respond to heat and electrical energy. You learned about conductors that transfer heat and electrical energy easily and insulators that don't. And you learned about how some materials change size when they gain or lose heat. You took notes on almost every page of the lesson, and now it's time to use them, as well as any other evidence presented, to compose your own multimedia project, or write a final essay, in which you describe and summarize all of that knowledge you've collected.
As you compose your project, try to think of ways to connect, either graphically or in writing, the ways heat and electrical energy interact differently with materials. One idea would be to create a concept map, handbook or even write a song that describes
• Conductors and insulators for both heat and electrical energy
• Thermal expansion or how materials change size when heat energy is added or removed
• How these properties make some materials better than others for different jobs.
Make sure to include definitions, comparisons, and descriptions.
If you create a multimedia project that requires a social-media, video, or audio platform that is not directly offered by this lesson, you will need to post it to a file-sharing site (Dropbox, Google Drive, and Microsoft Teams are examples) and then upload the link to the Write It plug-in. Here are some ideas for what you might want to do:
• Take images from the lesson to create an animation storyboard.
• Expand your notes and turn them into a script for a podcast.
• Compose and perform a rap or poetry slam.
• Make a video of yourself providing an oral explanation or commentary.
Use Organize It to outline your ideas. You can review your notes in “My Work” as well as any of the following videos and glossary terms.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
Thermal energy (aka heat) travels between and through materials by conduction. But not all materials are created equal-- some materials are really good at transferring heat energy. A metal spoon, for instance, heats up if it’s in a hot cup of tea. A wooden spoon? Not so much.
Materials that transfer heat fast and efficiently, are called conductors. And materials that don’t are insulators.
Metals, for instance, are some of the best conductors there are: Silver, copper, aluminum. While things like rubber, plastic, wood and even air, are good insulators. They don’t transfer heat efficiently.
What makes a material a good conductor or insulator doesn't only apply to heat energy. It applies to electrical energy as well. Copper wires transfer electricity from here to there, and rubber insulators, well, insulate.
So, why should you care? Well, conductors and insulators are used in everything. In your house, car, clothing, food packaging, and in any device, machine, or appliance that uses electricity. And knowing how, why, and how much materials conduct or insulate keeps our lives warm and cozy or cool and connected.
Organize It!: Your work has been submitted.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
As a material heats up, its molecules move around more. And as its molecules move around more, the space between molecules increases. This is called thermal expansion. The volume, shape or area of a material changes as it heats up. And the opposite happens as a material cools down. The molecules settle down close to one another, and the material shrinks or contracts. (footnote: *exception is solid water (ice))
Thermal contraction is why that pickle jar is a bear to open. And thermal expansion is why running it under warm water is the solution. That metal lid expands as it warms up which loosens its grip on the jar.
Different materials expand and contract in different ways and at different temperatures. And knowing at what temperatures and how much materials expand and contract is key in engineering lots of things. Bridges are built with metal strips so that they can expand and contract in hot or cold weather without breaking. Tires lose pressure on cold days. Power lines droop in hot weather. And old school thermometers tell your temperature. All of these are examples of thermal expansion and contraction.