1. Optics What is Light?

2. Light: A wave of energy that travels in straight lines which illuminates things.

3. Light travels at 300 000 km per second. (or 3 000 000 000 m per second) If light circled around the surface of the earth, it would travel 7 1 / 2 times around the earth in one second.

4. From the sun 149,600,000 km Can you figure out How long it takes For light to reach Earth?

5. The two types of light sources are luminous and non- luminous. Luminous light can be from natural or artificial sources. Some examples of natural sources of luminous light are the Sun, the Northern Lights, lava from volcanoes, and light produced from fireflies. Various artificial light sources include computer and television screens, a light bulb, and neon signs. Some non-luminous sources of light include mirrors, humans, the moon, books, and houses.

6. travels through different types of mediums (materials) 1.Transparent mediums - All light passes through Eg. Window (plate of glass)

7. 2. Translucent: - some light passes through, but not all Eg. Stained glass

8. 3. Opaque: - no light passes through object Eg. Wood, walls (drywall/cement)

9. Class Activity Can you think at least 3 everyday objects of each: transparent, translucent and opaque?

10. There are many different types of light emitted. The wave of each type has a different wavelength.

11. Electromagnetic Waves Believe it or not, you are being “showered” all the time, not by rain but by waves. DO NOT COPY DOWN

12. All waves are included on Electromagnetic Spectrum :

13. Different Wave Uses: 1.Radio waves: TV signals, Cell phones 2.Microwaves: microwaves, radar guns 3.Infrared waves: burglar alarms, infrared goggles, night vision 4.Visible Waves: Rainbows, Astronomy, human vision 5.Ultraviolet waves: Disinfect drinking water, Sun Rays, detective work, Gone in 60 Seconds car list 6.X-rays: Customs at airports to check luggage 7.Gamma rays: Very dangerous, used to kill cancerous cells (not make the Hulk).

14. Visible Light Spectrum: Light waves that we can see Different wavelengths emit different colours. ROY G. BIV are the colours we can see, if all wavelengths are shone together, white light is produced.

15. Colour Wavelengths

16. https://www.youtube.com/watch?v=gtgBHsSzCPE