Electromagnetic Radiation Ms. Samayoa Birmingham Community Charter High School Chemistry

Learning Objectives: Students will be able to name the properties of waves and be able to understand that electromagnetic radiation is composed of light that has a broad range of wavelengths Academic Vocabulary: Wavelength, frequency, amplitude, crest, trough, electromagnetic radiation, electromagnetic spectrum

Warm-up Doctors constantly tell you to put sunscreen to protect your skin from UV radiation. Cell phones also release radiation called radio waves but doctors don’t tell you to protect yourself from this type of radiation. With that said, what do you think is the difference between UV radiation and radio wave radiation?

Types of waves Mechanical waves are waves that require a medium Example: Sound Sound can travel through air, water, or solids, but it can’t travel through a vacuum It needs a medium to travel Electromagnetic waves are waves that can travel through a vacuum Example: light, microwaves, radio waves, and X-rays Doesn’t need a medium to travel

Think About It Sound cannot travel through a vacuum because it is a mechanical wave. Space has a vacuum. Taking that into consideration, how do you think astronauts communicate with each other in space?

Properties of Transverse Waves All electromagnetic waves are transverse waves Wavelength is the distance from one wave crest to another The frequency of a wave expresses the number of times a wave passes a given point in one second Amplitude of a wave is the height of the crest or depth of the trough with respect to the center line of the wave

Think About It Looking at the waves below, what can you say about the relationship between frequency and wavelength? In addition, how do the two waves below differ in energy?

Learning Check Frequency and wavelength have a _____________ (direct/inverse) relationship. As frequency increases, wavelength ______________ (increases/decreases). As frequency decreases, wavelength ______________ (increases/decreases). Frequency and energy of a wave are _____________ (direct/inverse) relationship. As frequency increases, energy of the wave _______________ (increases/decreases). As frequency decreases, energy of the wave ______________ (increases/decreases).

Learning Check Frequency and wavelength have an inverse relationship. As frequency increases, wavelength decreases. As frequency decreases, wavelength increases. Frequency and energy of a wave have a direct relationship. As frequency increases, energy of the wave increases. As frequency decreases, energy of the wave decreases.

Electromagnetic Radiation Electromagnetic radiation is a form of energy that is produced by a vibrating electric and magnetic field Electromagnetic radiation is both a particle and a wave

Electromagnetic Radiation Electromagnetic radiation travels at the speed of light = 299,792,458 meters per second How would we rewrite this number in scientific notation to only one significant figure? Write it as 3 x 108 meters per second

Electromagnetic Spectrum Light is a type of electromagnetic wave

Electromagnetic Spectrum The human eye can only see between 700nm (red) and 400 nm (violet) 1 nm = ___ m ROYGBV

Electromagnetic Spectrum

Brain Games Watch a video for ten minutes Please pay attention since you will have to answer questions about the video that is due at the end of the period Beginning Fast forward to 7:09