Light

Science FUNdamentals

Outline

• Electromagnetic Radiation
• Controlling light
• Colourful Fire

Electromagnetic Radiation

01

What is light?

• Form of energy called

“electromagnetic (EM) radiation.”

• We can see a very small portion of electromagnetic radiation → visible light.
• Other types: infrared, microwave, ultraviolet, x-rays

Snakes use Infrared radiation to aid them in hunting prey

LORDZB. “10 Unusual Animal Senses.” ListVerse, 13 Apr. 201AD, listverse.com/2013/04/13/10-unusual-animal-senses/?utm_source=more&utm_medium=link&utm_campaign=direct.

Fractured Leg

Scientist use x-rays to check the lungs of a patient

Human Butterfly Bee

Different animals can see different spectrums of light

Bees and Butterflies can see the ultraviolet spectrum

How Can We Tell the Type of Electromagnetic Radiation?

Question Time!

By the length of the wave!

Crest

Crest

Trough

Called Electromagnetic radiation because light has both an electrical component and a magnetic component

"Electromagnetic Spectrum - SNC2D." Google Sites. N.p., n.d. Web. Aug. 2020.

Invisible Ink

Credit: Chemistry Experiment Vector Illustration By Vecteezy

Controlling Light

02

How does light travel?

Fast

• Travels 300,000 kilometers per second!

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Straight

• Travels straight until something bends it. These straight paths of light are called light rays.

How can you control light?

Blocking it with something

• This creates a shadow.

Change its path with a mirror

• This is called a reflection.

Bend it

• Light changes direction when passing transparent material of a different density.

This is called a refraction.

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Reflection

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Light can reflect off surfaces like mirrors and water

Refraction

Water and ice are denser than air so light bends more

Can you name a few things that either emit or control light?

Question Time!

Arrow Refraction

Credit: Chemistry Experiment Vector Illustration By Vecteezy

Exploring Refraction

• Light can change its direction passing through transparent material
• Light’s Journey in this experiment: Air->Glass->Water->Glass->Air

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Light bending due to different materials

"Introduction to Shading." Introduction to Shading (Reflection, Refraction and Fresnel). N.p., 15 Aug. 2014. Web. 27 Aug. 2020.

Splitting up light

• White light is actually a combination of all the colors of the rainbow.

Spectroscopes

• Spectroscopes can show the different colors of light that make up white light

"Experiment #7: Light as a Tool." Lab #7: Analyzing Light: The Spectroscope. 2011. Web. Aug. 2020.

Candle Spectrometer

Credit: Chemistry Experiment Vector Illustration By Vecteezy

Can you split light without a spectroscope?

• YES! With a prism!

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Prism: Splitting Light

Credit: Chemistry Experiment Vector Illustration By Vecteezy

What else can produce this rainbow effect?

Question Time!

What about a laser?

• A laser is a special source of light of only one pure color (or wavelength).
• Since it is only one color, you can’t separate the laser light into different colors- but you can reflect it!

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Lasers

Credit: Chemistry Experiment Vector Illustration By Vecteezy

Polarizing Light

When the arrows are pointing up, they block the wave that is like the red wave. When the arrows are pointing sideways, they block the wave that is like the blue wave.

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Polarizing Filters

Credit: Chemistry Experiment Vector Illustration By Vecteezy

When one arrow is pointing up and one arrow is pointing sideways, all light is blocked

Colourful

Fire

03

Colourful Fire

• Sometimes chemicals give off specific colored waves of light when they are burned.
• An example of this in real life are fireworks!

Let’s look at some fireworks!

Fireworks Chemistry

• Light is a form of energy.
• Burning things makes light as heat energy. Ex-burning candles
• The substance burned is made of particles.
• Particles get excited by a flame & sometimes release energy (light!)

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The Chemistry of Fireworks

QUESTIONS?

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