9/24 & 9/25 - 7th Grade Agenda Learning Objective: Learn the difference between Amplitude and Wavelength Collect: Reading & Note Taking p.30 – 31 Pass back Graded HW, Test Text book Reading: p. 40 – 45 Video: Wave Video: Incredible journey of the Butterfly HW: Reading & Notetaking : p. 32 – 35 HW: Signed Grade Printout

Daily Reflection Prompt: What is the crest of the wave? What is the trough of a wave? Draw a wave and label crest and trough of a wave.

Wave A wave is a disturbance that transfer ene_____ from place to place. Who can give me examples of waves? rgy

Is light a wave? Yes But why?

Picture of Light Wave Image of a pulse of light that is 2.5 billionths of a millionth of a second long

Energy In science, energy is defined as the ability to do wo___. rk

Medium The material through which a wave tra____ is called a medium Who can give me examples of medium? vels

Does Light Waves need a medium? Scientist first thought that Light needed to travel through a medium. So they invented the idea of aether in space. They look for aether in outer space but they found nothing. So, Light Waves can travel without a medium even in a Vacuum of outer space.

Crest gh Hi___ point of a wave is called a crest

Trough ow L___ point of a wave is called a trough

Amplitude imum Amplitude is the max______ distance that the particles of medium carrying the wave move away from their rest positions. Which rope has higher amplitude?

Wavelength The distance between two corresp______ parts of a wave is its wavelength. Which rope has longer wavelength? onding

Frequency Wave frequency is the num_____ of complete waves that pass a given point in a certain amount of time ber

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? 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.

How do we use Infrared Rays? Conventional Oven Heat Lamps Thermograms

Visible Light makes up only a small part of the electromagnetic spectrum