Light and Optics

Question 1

Pythagoras

Answer 1

~500 BC
Thought light was beams that came out of your eyes in straight lines, like lasers
Issue: If this were true, we would be able to see in the dark.

Question 2

Euclid

Answer 2

~300 BC
Light Travels in a straight line
Light reflects off a mirror from the same angle it came

Question 3

Ptolemy

Answer 3

160 BC
Light beams bend when moving from air to glass

Question 4

Al Haytham

Answer 4

1000 AD
Accuratly identified how vision works
Light Bounces off objects and those rays travel to our eyes

Question 5

Isaac Newton

Answer 5

1672
Took an interest in light and the colour spectrum
He shone light through a prism and saw how white light is a mix of multiple colours

Question 6

Ole Rømer

Answer 6

1676
First to time the speed of light
214 000 m/s - outdated

Question 7

Albert A. Michelson

Answer 7

1879
Timed the speed of light between 2 mountains
This experiment allowed him to calcultae the speed of light as it travels through the Earth’s atmosphere
He won the 1907 Nobel Prize in science for his work

Question 8

What is Light?

Answer 8

Light is the energy in the form you can see.
- Radiant energy
- Travels in rays
- Can be transformed into other energy types when absorbed

Question 9

Name the 3 forms of light energy

Add examples for each

Answer 9

• Electrical Energy (solar panels)
• Thermal Energy (sunlight)
• Chemical Energy (photosynthesis)

Question 10

Properties of light

Answer 10

Light…
- Travels in straight lines
- Can be reflected
- Bends
- Form of Energy

Question 11

Name 2 Types of Light

Explain Each

Answer 11

BIOluminescence:
Light emitted by a living organism (plankton/jellyfish)
CHEMIluminescence:
Production of light from a chemical reaction (snapping glow stick)

Question 12

1.2

What is an Optical Device?

Answer 12

Any technology that uses light
(mirrors, telescopes)

Question 13

Microscope

When was it invented? What’s it do? What science originated from it?

Answer 13

• Has 2 lenses (ocular & objective)
• Invented in 1595
• Used to make smaller objects (blood cells, bacteria) appear larger
• Microbiology
• CONVEX LENS

Question 14

Binoculars

What do they do?

Answer 14

• Making far away objects appear closer
• Made up of 2 short refracting telescopes

Question 15

Telescopes

When/Where was the 2st T made? Who is a key individual?

Answer 15

1st Telescope was made in the Netherlands in the late 1600s
Galileo Galilei built himself a telescope and improved it. His discoveries:
- Craters on moon
- Objects circling Jupiter
- Venus has phases - like moon

Question 16

What are the 2 Types of Telescopes?

Answer 16

Refracting telescopes
Reflectng telescopes

Question 17

REFRACTING Telescopes

What do the lenses do?

Answer 17

Refracts light by using 2 lenses (one on each end of the long tube).
Larger Lens: Gathers light and focuses the rays towards the eyepiece

Question 18

REFLECTING Telescopes

Answer 18

Reflects light using 2 mirrors
A large circular mirror carves inward (concave mirror)
A second mirror takes the reflected light and directs it to the eyepiece

Question 19

2.1

Ray Diagrams

Why are they used? What do they do?

Answer 19

Scientists use ray diagrams to show how light travels in directions (by using straight lines that come from the source).
Ray diagrams help us see…
- how light travels in all directions
- how brightness (intensity) light changes with distance
- how shadows appear

Question 20

Describe 3 scenarios of ray diagrams

Answer 20

1) Looking up close at a flashlight (high intensity)
2) Looking far away from a flashlight (low intensity)
3) Shadow Information (picture sun and opaque person)