What is a wave?• A wave is a disturbance that transfers energy

through space and/or some medium. • There are two main types of waves:– Electromagnetic Waves transfer electric and

magnetic energy.• Can travel through empty space or a medium such as air.• The sun’s energy arrives on Earth as EM radiation.

– Mechanical Waves require a medium to transfer energy.• Cannot travel through empty space.• Examples: Sound waves, water waves, etc.

Wave Characteristics• All EM waves travel at the same speed in a vacuum,

but they have different wavelengths and different frequencies.

• Wavelength - the distance between the crest of one wave and the crest of the next wave.

• Frequency – the number of waves that pass a given point in a certain amount of time.– Higher frequency = more energy– Lower frequency = less energy

• Amplitude – the height of the wave

Electromagnetic Spectrum(EM Spectrum)

Foldable

Goal: Students will create a foldable that will help them understand the

electromagnetic spectrum.

Directions

• Follow the next 7 slides to create your Electromagnetic Spectrum Foldable

Fold your paper in half (hot dog style)

Make 6 marks across your paper of about equal distance as shown below.

Draw lines from the marks to the edge of the paper as shown below.

Cut across the red dashed lines shown below.

Draw this wave on your paper. Does not need to be exactly the same. The waves do need to get closer together as you move the right.

Add the information above the EM Spectrum diagram

__________ Wavelength__________ Frequency__________ Energy

__________ Wavelength__________ Frequency__________ Energy

Fill in the flaps below.Ra

dio

wav

es

Mic

row

aves

Infr

ared

w

aves

Visi

ble

light

Ultr

avio

let

wav

es

X-ra

ys

Gam

ma

rays

__________ Wavelength__________ Frequency__________ Energy

__________ Wavelength__________ Frequency__________ Energy

Electromagnetic Spectrum

• You will watch a short video about each kind of electromagnetic wave. While watching these videos, write down the following information about the kind of wave. Fold your foldable in half. This information should go underneath the flap of the specific kind of wave. If you are writing down information about radio waves, then flip the radio wave flap up and write down the information about radio waves.1. Relative wavelength2. Relative frequency3. Uses4. Hazards

Radio waves

• Longest wavelengths• Lowest frequencies• Used in broadcasting• No known hazards

Microwaves

• Wavelengths are shorter than radio waves• Frequencies are higher than radio waves• Used in radar guns, microwave ovens, cell

phones• No known hazards

Infrared waves

• Wavelengths are shorter than microwaves• Frequencies are higher than microwaves• Used in heat lamps, infrared cameras, and

remote controls• No known hazards

Visible light

• Wavelengths are shorter than infrared waves• Frequencies are higher than infrared waves• White light can be separated into the colors

red, orange, yellow, green, blue, and violet (ROY G. BIV)

Visible light

• Red light has the longest wavelength and shortest frequency of visible light• Violet has the shortest wavelength and highest

frequency of visible light• Uses: We can see it!• No known hazards

Ultraviolet waves

• Wavelengths are shorter than visible light waves• Frequencies are higher than visible light waves

Ultraviolet waves

• Used in bug zappers, black lights, tanning beds, fluorescent bulbs, and in detecting real versus forged documents, money, and credit cards

• Energy is great enough to damage or kill living cells. Can cause sun burn, which may eventually lead to skin cancer.

X-rays

• Wavelengths are shorter than ultraviolet waves• Frequencies are higher than ultraviolet waves• Can penetrate most matter. Used in x-ray machines to

view bones or items in luggage.• Too much exposure can damage cells leading to

cancer or even kill cells.

Gamma rays

• Shortest wavelengths• Highest frequencies• Most penetrating of all waves. Gamma

radiation is used to kill cancer cells.

Gamma rays

• Exposure to good cells can damage them causing cancer or even kill them.