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Reflection. Reflection occurs when a wave strikes an object and bounces off of it. Light. Mirror. Reflection. Reflection occurs when a wave strikes an object and bounces off of it. Light. Mirror.
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Reflection • Reflection occurs when a wave strikes an object and bounces off of it Light Mirror
Reflection • Reflection occurs when a wave strikes an object and bounces off of it Light Mirror
The law of reflection says that light reflects (bounces) off of an object at the same angle at which the light hits it.
LAW OF REFLECTION The angle of reflection must equal the angle of incidence
Examples of Reflection • Light bounces off a mirror • Bats use echolocation (sound waves bounce off of other objects)
REFLECTION EXAMPLE #2 Tinted windows on a car • Tinted windows make it cooler inside cars by reflecting light away from the window. • Reflection keeps heatout! • What wave carries heat that we learned about from the EM spectrum?
Two Types of Reflection Flat surfaces reflect perfectly! Rough surfaces reflect all over the place!
Refraction • Refraction is the bending of a wave caused by the change in its speed as it moves from one medium to another • What are some mediums that waves travel through? • Does light need a medium to travel? Liquids, Air, Solids NO! It can travel through SPACE!
New Vocabulary • Opaque- not able to be seen through • Transparent- see through
When does it reflect/refract? • If an object is opaque, the light will reflect because light cannot pass through a solid object. • Mirror • A book • If an object is transparent, the light will refract because light can pass through the object. • Water • Prism
Refraction of Light in Water • Light travels faster in air than in water • (water is more dense than the air…same goes for glass or any other medium more dense than air) • Because of this difference in speed, refraction causes underwater objects to appear closer to the surface than they really are
Refraction (Slowing Down) • When a wave passes into a medium that makes it slow down,the wave will bend toward the normal Air Water
Refraction (Slowing Down) • When a wave passes into a medium that makes it slow down,the wave will bend toward the normal Air Water
Refraction (Speeding Up) • When a wave passes into a medium that makes it speed up,the wave will away from the normal Air Water
Refraction (Speeding Up) • When a wave passes into a medium that makes it speed up,the wave will away from the normal Air Water
Will this light wave reflect or refract as it hits the water? AIR WATER
1) What is the angle of incidence? 2) Will the light bend toward the normal or away? 3) Who will see the light bulb directly? AIR WATER
A B Glass Air 1) What is the angle of incidence? 2) Will the light bend toward the normal or away? 3) Who will see the light bulb directly?
Glass Air 1) What is the angle of incidence? 2) Will the light bend toward the normal or away? 3) Who will see the light bulb directly?
1) Which medium is more dense? 2) Will the light bend toward the normal or away? 3) Who will see the light bulb directly? AIR WATER
Practice • Level 0 • If you have a question raise your hand and I will come to you. • If I am working with someone else, look back at your notes before I can come help you.
Exit ticket 1. ____________ Which of the following statements is true? a) refraction refers to a wave bouncing off of an object b) reflection refers to a wave bending as it travels from one medium to another c) refraction occurs due to a change in the speed of a wave d) reflection occurs due to a change in the amplitude of a wave 2. ____________ In which of the following situations would refraction occur? a) light hits a mirror and bounces off b) a person shouts inside a large cave, creating an echo c) bats use echolocation to develop an awareness of their surroundings d) light bends as it passes from water to air