# Energy Unit Week 34 Directions 1.Prepare your desk for science. Science notebook 2.Use voice level 0 (no voice) to review your light energy notes from.

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Energy Unit Week 34 Directions 1.Prepare your desk for science. Science notebook 2.Use voice level 0 (no voice) to review your light energy notes from notebook pg. 83.

Targets & Warm Up Targets: Students will understand how light can be reflected, absorbed, or refracted. Warm Up: How does light travel?

How does light travel? Light travels in straight lines called __________ that fan outward from the source of light. BUT Light can change when it strikes (hits) an object. Reflect Absorb Refract rays

Reflection Occurs when light waves bounce, or reflect, from a surface back to our eyes Some objects reflect more light rays than others

Absorption Occurs when an object takes in the light wave After a light wave is absorbed, it becomes a form of heat energy

Color and Light We see colors because objects reflect and absorb light. An object is a certain color because it absorbs all colors except for the color that it reflects back to our eyes.

Color and Light

Reflect? Absorb?

Color & Light What color is reflected? What color(s) are absorbed? Reflected: Red Absorbed: All other colors Reflected: None Absorbed: All colors Reflected: All colors Absorbed: None

Letting Light Through (Transmission) Transparent: Let most light rays pass Translucent: let some light rays pass Opaque: Do not let any light rays pass

How Light Changes Direction Light travels fastest through outer space where there is no matter Light slows as it travels through various mediums – Travels slowly in a gas – Travels more slowly in a liquid When light moves at an angle from one medium to another, some light… – Is reflected or absorbed – Passes through and changes directions (bends)

Refraction The bending of light caused by the change of speed that occurs when the wave passes from one medium into another Light travels from the pencil through water, though a glass, and through the air to your eye

Refraction

Lenses Lenses are curved pieces of clear glass or plastic that refract light that passes through them Two types: – Concave – Convex

Convex Lens Thicker in the middle than at the edges Light rays bend in toward the middle of the lens Makes things appear larger Found in magnifying glasses and microscopes

Concave Lens Thinner in the middle than at the edges Light rays bend out and spread apart Makes things appear smaller

Telescopes Concave and convex lenses are often used together to make details look sharper

StudyJams Video Light absorption, reflection, and refraction http://studyjams.scholastic.com/studyjams/jam s/science/energy-light-sound/light-absorb- reflect-refract.htm

Extra Time? Pretend that you are shining a flashlight on these objects. Do the objects reflect, absorb, or refract light?

Reflection Questions What is reflection? What is absorption? What is refraction? What are some examples of when light is reflected, absorbed, or refracted?

Homework

Targets (Revisited) Students will understand how light can be reflected, absorbed, or refracted.

Homework SubjectHomeworkDue Date ScienceLight Energy worksheetWednesday (tomorrow)

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