energy unit week 34 directions 1.prepare your desk for science. science notebook 2.use voice level 0...
TRANSCRIPT
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)