1. What is Light? A wave of energy that can pass through transparent and translucent substances

2. Learning Goals All students will know the properties of light Students will be able to explain the electromagnetic spectrum

3. Light… can pass through a vacuum like the one found between the Sun and the Earth – a vacuum is an area with no matter, not even air is a type of electromagnetic wave – These include radio waves, microwaves, infrared light, visible light, UV light, x-rays and gamma rays (used in cancer treatment)

4. Electromagnetic Spectrum Visible light makes up only a small fraction of the spectrum

5. Sources of Light

6. 2.Fluorescence: when a substance absorbs high-energy UV radiation and then immediately releases energy as visible light

7. 3.Light-Emitting Diode (LED): special materials create various colours of light, but very little heat, using electricity

8. 4.Chemiluminescence: production of light through a chemical reaction that produces no heat Some animals use this process to create light in a process called Bioluminescence

9. To Do: Complete questions 1-5 on page 429