1. Reflection and Refraction of Light

2. Reflection of Light Every object absorbs some light and reflects some light Why is the sun different? – The sun makes its own light – The light that comes from your table to your eyes is from the sun or a lamp and then reflects to your eyes How can we trace light? – Ray diagrams are used to trace the path of light

3. Ray Diagrams

4. How does light reflect? Light reflects at an angle Rough surfaces - light that strikes the surface will be reflected at all angles – Called DIFFUSE REFLECTION Smooth surfaces – light that strikes a smooth surface like a mirror will all reflect in a single direction

5. How do you see something? Light from the sun appears white, however when shone through a prism, it will separate into various colors (visible spectrum of electromag. waves) Objects have color because they reflect certain wavelengths of light

6. Why does a plant appear to be green? It absorbs the other wavelengths and reflects the green light (550 nm) Light really is not “green” – your brain interprets light at certain wavelengths as certain colors Petals of a red rose look red because they absorb wavelengths and then reflect the red light

7. Black is not a color – it is the absence of color

8. Refraction of Light What happens to light waves when they travel? Through empty space – travel in straight line Refraction – how light bends when passing from one medium to another Light changes direction because the speed of light is different in different mediums

9. How is light refracted? When light goes from traveling fast to a medium where it is traveling more slowly, the ray will be bent toward the normal Like one wheel of a lawnmower hitting the grass Like a car wheel going into the sand When light goes from traveling slower to a medium when it is traveling faster, the ray is bent away from the normal

11. How do objects appear if light is refracted? Objects appear to be in a different position The path of the light is changed as it goes from one medium to another However the brain still sees it as though the light traveled in a straight line So, the position of the object (cat of fish) looks different than where it really is

12. Diffraction Diffraction is the BENDING of waves around an edge. – Ex- Hearing sound waves from around a corner – When waves pass the edge of an object or pass through an OPENING, they spread out as if a new wave were created there. – Diffraction is the reason a SHADOW never has perfectly sharp edges.