Energy Unit Week 34 Directions 1.Prepare your desk for science. Science notebook 2.Use voice level 0...
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Transcript of Energy Unit Week 34 Directions 1.Prepare your desk for science. Science notebook 2.Use voice level 0...
Energy UnitWeek 34
Directions1.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
Table of Contents
Date Title Page5-19-15 Behavior of Light 84
Once you are finished with the Table of Contents, go to page 84 and add the title and date to the top of the page.
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 & LightWhat color is reflected? What color(s) are absorbed?
Reflected: RedAbsorbed: All other colors
Reflected: NoneAbsorbed: All colors
Reflected: All colorsAbsorbed: 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
TelescopesConcave and convex lenses are often used together to make details look sharper
StudyJams Video
Light absorption, reflection, and refraction
http://studyjams.scholastic.com/studyjams/jams/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
Subject Homework Due DateScience Light Energy worksheet Wednesday
(tomorrow)