Unit C Introduction Light and Optical Systems
Completion requirements
Unit C: Introduction to light and optical systems.
Watch
Watch the following introduction video for Unit C. You will see five questions during the video. Think about the questions, and think about other things you would like to learn as you study light and optics.
Unit C Introduction: Light and Optical Systems
Figure C.I.1 โ The Sun produces light that travels to Earth.
Several natural forms of light reach our eyes on Earth. Where does this light come from?
Most of the light we see on Earth comes from nuclear reactions in the Sun. All living things on Earth depend on light energy from the Sun. Photosynthesizing organisms like plants and some bacteria use light energy to make their own food. Organisms higher in the food chain, like humans, eat photosynthesizers for energy.
Burning fuels produces light on Earth. However, fuels like wood and fossil fuels come from once-living things, so their stored energy can also be traced back to the Sun.
Dimmer lights appear on Earth at night. Light reaches Earth from nuclear reactions in far-away stars. The Moon reflects light from our Sun. The colourful Northern Lights occur when high-energy particles from the Sun collide with gas particles high in Earthโs atmosphere.
Modern humans create light using electricity. We use electricity to produce light for many technologies, like lasers. We use light to send digital information around the world. We use electric lights to see at night.
Figure C.I.2 โ Earthโs moon reflects the Sunโs light.
Figure C.I.3 โ Particles from the Sun collide with Earthโs atmosphere to create the Northern Lights.
Watch More
Northern Lights
The Northern Lights, or Aurora Borealis, are a spectacular natural light display. Watch this videography of the Northern Lights.
The Northern Lights, or Aurora Borealis, are a spectacular natural light display. Watch this videography of the Northern Lights.
An Inuit legend tells that the Northern Lights are ancestor spirits playing a traditional soccer-like ice game. Watch this video to hear more from an Inuit elder.
Questions to Think About:
- What is light and how does it behave?
- How does light create images in eyes and cameras?
- How do humans use light in useful technologies?
Words to Think About:
Check the word cloud below. It pictures the important words you will learn in this unit. Likely, you will know many, but check new words or any that seem fuzzy to you! Watch for these words and combinations of these words as you read. When you see them
highlighted, you can click them to learn more about their meanings. You can also visit the course glossary and read definitions for all of these words.
Unit C: Checklist and Key Ideas
Focus On: Light and Optical Systems
This unit has three sections. Each section has a key idea that will help you learn more about light and optical systems. As you work through the unit, you will complete four tasks (one at the end of each section and one unit project) that will count for marks.
On the next page is a checklist of the tasks you need to complete for the unit. On the page after that are the key ideas, lesson titles, and key questions for this unit. Note that you can reach these two pages whenever you want by clicking the "Key Ideas" and "Unit Checklist" on the top corner of almost every page in the unit.
This unit has three sections. Each section has a key idea that will help you learn more about light and optical systems. As you work through the unit, you will complete four tasks (one at the end of each section and one unit project) that will count for marks.
On the next page is a checklist of the tasks you need to complete for the unit. On the page after that are the key ideas, lesson titles, and key questions for this unit. Note that you can reach these two pages whenever you want by clicking the "Key Ideas" and "Unit Checklist" on the top corner of almost every page in the unit.