Unit 3: Light and Optics

The unit goal: We have been commissioned by the Telus Spark to develop exhibits that allow our visitors to experiment, try things, build things and play. Our exhibits will use the concepts of light and optics that we will study over the next 3 weeks.

The grade 8’s will create a science center for the grade 5’s, and then open it up to the community.

The unit goal:

It takes a core set of skills to create something new, whether it’s a groundbreaking discovery or a toy robot. At MCMS Spark, we want to invite our visitors to hone their skills: use imagination to see beyond what exists, curiosity to formulate a question and persistence and problem-solving skills to take a risk, and to keep going and growing confidence.

We don't just relay information; we are a role model and force for innovation that drives positive change, we’re here to provide the tools to empower visitors to engage in the process of science -MCMS Spark’s goal is to help visitors engage in the process of science and inspire people to ask questions and seek out answers through investigation and reflection.

Our participatory exhibits are designed to encourage visitors, from children to adults, to pursue new ways of discovering the science behind light and optics and the ways in which this science improves our world or solves a problem.

Our goal is to create exhibits that encourage the following in our visitors •Engagement •Creation of conversation and new ideas •Creativity and Innovation •Collaboration •Risk Taking •Problem Solving Adapted from Telus spark Watch this video:

Light and Optical Systems Science 8: Unit 3

Topic 1, Lesson 1: What is light?

I can: • Define Light • Identify types and sources of light

What is Light?

• • Light is all around us

What inventions use light?

Can you think of more than Mrs. D did? She got 9 • • • • • • • Light bulbs/flashlights Infrared remote controls Microwave oven Lasers Camera Eye glasses Microscope/telescope/binoculars

What will we learn in this unit?

• • • • • • What is light?

• • • How does light behave?

Geometric Ray Model Reflection (in different types of lenses) Refraction (through different mediums) • • • Light-based technology that extends our vision binoculars, telescopes, microscopes • Color spectrum, primary colors What kind of energy comes from light?

Radiant energy Infrared, radio, ultraviolet, X rays, gamma rays • How does light travel?

The Wave Model

Think of some natural light sources:

(i.e. NOT man made) • • • • The sun stars fire sparks

The Sun’s Energy

• • How does light spread out from the sun?

it radiates in all directions • What does that look like?

The Sun’s Energy

con’t • • Energy transfer that does not require matter is called radiation.

Energy/light that travels by radiation is called radiant energy.

Cool fact

• Less than one tenth of one millionth of a percent (1/10 000 000% or 0.000 000 01%) of the sun’s rays actually reach us on earth.

What would we do without you?

• Why are we totally dependent on the sun’s energy?

• • • it is our largest natural light source it keeps us warm • • it lets plants (producers) carry out photosynthesis continues the oxygen cycle • we (consumers) eat plants. No plants = no food!

When the sun is asleep...

• We use artificial lights • • Do these lights have energy?

If so, they should be able to cause changes in matter...

What would happen if...

...we placed a black piece of paper under a lamp for a few minutes?

It heats up!

Can you think of some real-life examples of light changing to heat?

What would happen if... It’s a sunny day and you...

• Wear a black shirt • Sit on dark upholstery in a car

1st principle of light:

• Light is a form of....

Energy !

• When it is absorbed by a surface, it can be transformed into several forms of energy • • • • thermal energy (heat) i.e. temperature rises • electrical energy i.e. solar powered calculator • chemical energy i.e. during photosynthesis

Sources of light

• Imagine if we had no artificial light...

• • • • • • We wouldn’t have: TV computers lamps theatre lighting life after dark!

The sources of light

Let’s look at the sources of artificial light...

Fill the information into your chart

Incandescent Source

• What is it?

• When something gets so hot that it gives off visible light • ever touched an old-style light bulb and gotten burned?

• Energy transformation: • Electrical Energy --> Thermal Energy --> Visible Light Energy 95% of the energy given off by an incandescent light bulb is released as HEAT.

Fluorescent Sources

• What is it?

• • High energy UV light is absorbed by particles • The particles emit this light.

ener gy as visible This ‘glow’ is called fluorescence Energy transformation: Electrical energy -->Ultraviolet light Energy --> Energy absorbed by particles --> Visible Light Energy

Fluorescent tubes

Look at the next page in your handout • filled with mercury vapour.

• an electric current stimulates the vapour, causing it to give off UV rays • UV rays are absorbed by the particles in the phosphor coating • causes the coating to glow --> and we have light.

Benefits?

• energy efficient (less energy wasted as heat)

Phosphorescent Sources

• What is it?

• • • Similar to fluorescent: Particles absorb light energy, but they can store it for a while.

• The result?

Glow-in-the-dark!

Chemiluminescent Sources

• What is it?

• Chemicals mix, react, and give off visible light • • In the glow stick: • 2 chemicals are kept separated by a barrier. • Break the barrier by bending the stick • the chemicals mix --> chemical reaction that emits visible light Energy transformation: Chemical Energy --> Visible Light Energy

Bioluminescent Sources

• • What is it?

• An animal has a chemical reaction inside its body that causes it to emit visible light Examples?

• • • Some fish/jellyfish: To attract prey & warn off predators fire flies: To attract a mate fungi in caves

Do you get it?

With your table group, brainstorm more examples of each source of light Add your examples to your table.