10/13 & 10/14 - 7th Grade Agenda

Collect: HW: Reading & Note Taking : p. 35 & 36Pass back HW & TestTransparent, Translucent and OpaqueChap1 Test & Reflection for Absent studentsStereo Microscope Lab Class Reading: p. 45 - 48HW: Cell Activities (Stereomicroscope)

Electromagnetic Wave

• An electromagnetic wave consists of vibrating electric and magnetic field that move through space at the speed of lig____ht

What are some examples of electromagnetic waves?

• Radio Waves• TV Signals• Microwaves• Infrared rays• Light• Ultraviolet rays• X-Ray

How fast do electromagnetic waves travel?

• It is the fastest thing in the universe• 300,000 km per second• 186,000 miles per second• It takes 8 minutes for light to travel from the sun

to the earth• It takes 3 million years for light to travel from the

nearest galaxy (andromeda) to the earth

Electromagnetic Wavelength

How do we use Radio Waves & Microwaves?

• Radio & TV signals

• Microwave Oven

• Radar

• MRI

• Cell phone

Using Microwaves

• Why do you see sparks you put metal objects in a microwave?

• Because of the build up of electrical energy in the metal

• The long wave length of Microwaves can pass right through glass and plastic. That is why microwaves do not heat glass and plastic containers.

Cell phone towers• These towers are placed 1 -2

miles apart in a city• They use M______wave to

communicate with cell phones

• They can be used to locate the loc_______ of the caller.

icro

ation

How do we use Infrared Rays?

• Conventional Oven• Heat Lamps• Thermograms

Visible Light makes up only a small part of the electromagnetic

spectrum

Transparent Materials

• Transparent material trans_____ most of the light that strike it.

mit

Translucent Materials

• A translucent material sca____ light as it passes through, just as smoke, fog, and clouds scatter light as it passes through the air.

tters

Opaque Materials

• An opaque material refl_____ or absorbs all of the light that strikes it.

ects

Why does the apple appear red?

• Because the red light reflect it.

• All other light are absorbed.

What do you notice about the apple when it is shown in red

light?

What do you notice about the apple when it is shown in green

light?

What do you notice about the apple when it is shown in blue

light?

What are the three primary colors of light?

• Red, Blue, Green

What are the three primary colors of pigment?

• Yellow, Magenta, Cyan

• What color do you get when you combine the three primary colors of pigment?

Why do three primary colors of pigments produce black instead

of white?• As pigments are added together, fewer

colors of light are reflected and more are absorbed