Waves of the Electromagnetic Spectrum Chapter 9 Lesson 1

Standards SC.7.P.10.1: Illustrate that the sun’s energy arrives as radiation with a wide range of wavelengths, including infrared, visible, and ultraviolet, and that white light is made up of a spectrum of many different colors. (L) SC.7.P.10.3: Recognize that light waves, sound waves, and other waves move at different speeds in different materials. (L) SC.8.E.5.11: Identify and compare characteristics of the electromagnetic spectrum such as wavelength, frequency, use, and hazards and recognize its application to an understanding of planetary images and satellite photographs. (H) SC.7.P.10.2: Observe and explain that light can be reflected, refracted, and/or absorbed. (H)

Learning Goal Students will be able to identify, compare and contrast characteristics of the electromagnetic spectrum and its interaction with matter.

Essential Questions How does the sun’s energy arrive on earth? How do electromagnetic waves compare? What makes up the electromagnetic spectrum?

How Does the Sun’s Energy Arrive on Earth? The sun’s energy arrives on Earth as electromagnetic radiation. Vocabulary Radiation – the transfer of energy by electromagnetic waves *Electromagnetic wave – a wave that can transfer electric and magnetic energy

How Does the Sun’s Energy Arrive on Earth? Electromagnetic Wave Animation

How Does the Sun’s Energy Arrive on Earth? What can electromagnetic waves travel through? Empty Space Gases (ex. Air) Liquids (ex. Water) Solids

How Does the Sun’s Energy Arrive on Earth? What can electromagnetic waves travel through? Empty Space (Contains no matter) Gases (Contains matter) Liquids (Contains matter) Solids (Contains matter) *Medium – a substance that contains matter through which waves can travel through EM. Waves do not require a medium to travel through.

How Does the Sun’s Energy Arrive on Earth? *Characteristics of EM. Waves Electrical and magnetic properties Electric and magnetic field are at right angles (90°) to each other Does not require a medium to travel through Travels fastest in: vacuum (empty space) > gas > liquids > solids

Characteristics of Waves Crest Crest Crest Trough Trough Trough *Crest – highest most point on a wave *Trough – lowest most point on a wave

Characteristics of Waves Wavelength Wavelength *Wavelength - the distance between the crest of one wave to the crest of another wave

Characteristics of Waves Amplitude Amplitude *Amplitude – the maximum displacement or vibration of a particle in a wave.

Characteristics of Waves What is a complete wave?

Characteristics of Waves

Characteristics of Waves High Frequency Short Wavelength *Frequency - the number of complete waves that pass a given point in a certain amount of time. Wavelength - the distance between the crest of one wave to the crest of another wave Low Frequency Long Wavelength

How Do EM. Waves Compare? All EM. Waves travel at the same speed in a vacuum. They have different wavelengths and frequencies.

What Makes Up the EM. Spectrum? The EM. Spectrum is made up of radio waves, microwaves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays.

RADIO WAVES Have the longest wavelengths and lowest frequencies of all the electromagnetic waves.

Global Positioning Systems (GPS) measure the time it takes a radio wave to travel from several satellites to the receiver, determining the distance to each satellite.

A radio picks up radio waves through an antenna and converts it to sound waves. Each radio station in an area broadcasts at a different frequency. # on radio dial tells frequency.

(MAGNETIC RESONACE IMAGING) MRI (MAGNETIC RESONACE IMAGING) Uses Short wave radio waves with a magnet to create an image.

MICROWAVES Have the shortest wavelengths and the highest frequency of the radio waves.

Used in microwave ovens. Waves transfer energy to the water in the food causing them to vibrate which in turn transfers energy in the form of heat to the food.

RADAR (Radio Detection and Ranging) Used to find the speed of an object by sending out radio waves and measuring the time it takes them to return.

Shorter wavelength and higher frequency than microwaves. INFRARED RAYS Infrared= below red Shorter wavelength and higher frequency than microwaves.

You can feel the longest ones as warmth on your skin Warm objects give off more heat energy than cool objects.

Heat lamps give off infrared waves. Thermogram—a picture that shows regions of different temperatures in the body. Temperatures are calculated by the amount of infrared radiation given off. Heat lamps give off infrared waves. Therefore people give off infrared rays.

VISIBLE LIGHT Shorter wavelength and higher frequency than infrared rays. Electromagnetic waves we can see. Longest wavelength= red light Shortest wavelength= violet (purple) light

When light enters a new medium it bends (refracts) When light enters a new medium it bends (refracts). Each wavelength bends a different amount allowing white light to separate into it’s various colors ROYGBIV.

ULTRAVIOLET RAYS Shorter wavelength and higher frequency than visible light Carry more energy than visible light

Used to kill bacteria. (Sterilization of equipment)

Too much can cause skin cancer. Use sun block to protect against (UV rays)

Causes your skin to produce vitamin D (good for teeth and bones)

X- RAYS Shorter wavelength and higher frequency than UV-rays Carry a great amount of energy Can penetrate most matter.

Bones and teeth absorb x-rays Bones and teeth absorb x-rays. (The light part of an x-ray image indicates a place where the x-ray was absorbed)

Too much exposure can cause cancer (lead vest at dentist protects organs from unnecessary exposure)

Used by engineers to check for tiny cracks in structures. The rays pass through the cracks and the cracks appear dark on film.

GAMMA RAYS Shorter wavelength and higher frequency than X-rays Carry the greatest amount of energy and penetrate the most.

Used in radiation treatment to kill cancer cells. Can be very harmful if not used correctly.

The Incredible Hulk was the victim of gamma radiation.

Exploding nuclear weapons emit gamma rays.

Brief SUMMARY A. All electromagnetic waves travel at the same speed. (300,000,000 meters/second) in a vacuum. B. They all have different wavelengths and different frequencies. Long wavelength-lowest frequency Short wavelength highest frequency The higher the frequency the higher the energy.

Electromagnetic Spectrum Foldable Activity

Step 1: Fold the paper given to you in half hot dog style.

Step 2: Using a ruler, make 6 marks across your paper of about equal distance (40 cm apart) along the crease.

Step 3: Cut from the side of the paper towards each mark to make flaps Step 3: Cut from the side of the paper towards each mark to make flaps. Do not cut past the crease (fold) on the paper.

Step 4: Draw the waves illustrated below on your paper.

Instructions: On the outer flaps above the wave, label the appropriate EM. Wave from left to right Above or below the wave you drew, label which side has the following: a. long/short wavelength b. high/low frequency c. high/low energy On the back of the flap, write: a. Characteristics b. Uses c. Useful and/or hazardous

Instructions: On the outer flaps above the wave, label the appropriate EM. Wave from left to right

Outside Flaps Ultraviolet Rays Infrared Rays Radiowaves Microwaves Visible Light Ultraviolet Rays X-rays Gamma Rays

Instructions: Above or below the wave you drew, label which side has the following: a. long/short wavelength b. high/low frequency c. high/low energy

Outside Flaps Ultraviolet Rays Infrared Rays Radiowaves Microwaves Visible Light Ultraviolet Rays X-rays Gamma Rays Long Wavelength Short Wavelength Low Frequency High Frequency Low Energy High Energy

Instructions: On the back of the flap, write: a. Characteristics b. Uses c. Useful and/or hazardous

Radiowaves Longest wavelengths, Lowest frequencies Used in broadcasting to carry signals for radio programs Useful

Microwaves Have shorter wavelengths and higher frequencies than radio waves Used in microwaves to cook food, cellular phones, radar guns Useful

Infrared Rays Have shorter wavelengths and higher frequencies than microwaves Used in heat lamps to keep things warm. Also used in infrared cameras to detect heat. Useful

Visible Light Have shorter wavelengths and longer frequencies than infrared rays. White light can be separated into red, orange, yellow, green, blue, and violet (ROY G BIV) Red has the longest wavelength and lowest frequency. Violet has the shortest wavelength and highest frequency.

Ultraviolet Rays Shorter wavelengths and higher frequencies than visible light. Energy is great enough to damage or kill living cells. Too much exposure can burn your skin. Small doses can cause skin cells to produce vitamin D. Useful and Hazardous

X-rays Shorter wavelengths and higher frequencies than ultraviolet rays Can penetrate most matter. Can be used to make images of bones and teeth. Too much exposure can cause cancer. Useful and hazardous

Gamma Rays Shortest wavelengths and highest frequencies Most penetrating of all waves. Can be used to examine the body’s internal structures. Useful and hazardous.

Reflection Chapter 9 Lesson 2

Learning Goal Students will be able to identify, compare and contrast characteristics of the electromagnetic spectrum and its interaction with matter.

Essential Questions What are the kinds of reflection?

Things You Need to Know About Light Light travels in straight lines as rays Each line is called a light ray

What’s the difference in reflection?

What’s the difference in reflection?

What’s the difference in reflection?

Let’s Test Our Hypothesis! What happens when we shine a laser pointer at a smooth surface? What happens when we shine a laser pointer at a rough or uneven surface?

What Are the Kinds of Reflection? The two ways in which a surface can reflect light are regular reflection and diffuse reflection.

What’s the difference in reflection? Diffuse Reflection Regular Reflection

What Are the Kinds of Reflection? Regular reflection – reflection that occurs when parallel rays of light hit a smooth surface and all reflect at the same angle. Diffuse reflection - reflection that occurs when parallel rays of light hit an uneven surface and all reflect at different angles.

Refraction Chapter 9 Lesson 3

Learning Goal Students will be able to identify, compare and contrast characteristics of the electromagnetic spectrum and its interaction with matter.

Essential Questions What happens when light hits an object? What factors affect the speed of an electromagnetic wave?

What Happens When Light Hits an Object? When light hits an object, it can be reflected, refracted, and/or absorbed. What absorbs more light? Your science table or a window? The more transparent an object is, the less light it will absorb. Objects absorb all but one specific color (specific wavelength/frequency). That one specific color is reflected, which is why objects appear to be that color.

What Happens When Light Hits an Object? We already know how light reflects. What does refracted mean?

Have you ever seen something like this before? What about this?

What has happened to the light rays coming from the straw? The light rays are bending!

What Happens When Light Hits an Object? Refraction – the bending of light rays as they pass from one medium to another. Why do you think the light ray depicted to the right are bending that way as they pass from air to water to glass and back into air?

What Happens When Light Hits an Object?

The water droplet is transparent, so the light does not get absorbed. Each color of light reflects off the back surface of the water droplet. When white light enters the water droplet, each color is refracted by a different amount. Each color of light is refracted again as it exits the water droplet.

What Factors Affect the Speed of an Electromagnetic Wave? The speed of an electromagnetic wave through a substance is determined by the substance’s physical properties.

Class work/Homework Pages 311-312 #1-6, 13-15 Page 313