Lesson 6 — 6.4 + 6.5

Science P4

The speed of light
&
Reflection
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Slide 1: Slide
Speed of light + reflectionMiddelbare schoolhavo, vwoLeerjaar 2

This lesson contains 28 slides, with text slides and 1 video.

Items in this lesson

Science P4

The speed of light
&
Reflection

Slide 1 - Slide

This lesson
  • Completing the speed of light
  • Reflection — Phet simulation
  • The practical

Slide 2 - Slide

Learning goals
  • Name the speed of light and it's name in physics
  • Explain how the speed of light us used as a unit of distance
  •  Explain how astronomers use light to study space
  •  Be able to do calculations using the speed of light

Slide 3 - Slide

  • During class – have a question, raise your hand.

  • When working  together, do not talk with or shout to people on the other side of the class.

  • While working independently, do not disturb the class.

  •  Participate seriously in the class (also when working with our phones). do not make noise, inappropriate jokes, chat with everyone around you, shout through the class, etc.

  • After one warning, when you break the rules again— You go to olc 2 with extra work.

Slide 4 - Slide

Recap
Speed of light

What did we learn about the speed of light?

Slide 5 - Slide

what is the speed of light?

Slide 6 - Slide

300 000 000 m/s
Of  300 000 km/s

Slide 7 - Slide

What is the symbol for the speed of light?

Slide 8 - Slide

c
'Celerity'
Latin for Swift

Slide 9 - Slide

In astronomy light is used as a unit of...

Slide 10 - Slide

Distance
Light years

Slide 11 - Slide

Measuring the speed of light

Slide 12 - Slide

Calculations with the speed of light

Slide 13 - Slide

Calculate how long it would take in minutes for light to travel from the Sun to the Earth in.

Slide 14 - Slide

Given
  • Speed of light = c = 300 000 000 m/s = 300 000 km/s
  • Distance = 150 000 000 km

Asked
  • How long does it take for light of the sun to reach the Earth.

Formula
  • v = d/t        t = d/v

Calculation
  • t = 150 000 000 / 300 000 = 500s
  • 500s / 60 = 8.3 minutes (8 minutes and 18 seconds)

Slide 15 - Slide

Exercise
The closest star to our sun is Proxima Centauri. This star is 40,208,000,000,000 km away from our sun. 

The speed of light is 9 460 000 000 000 kilometers per year.

How many light years away is Proxima Centauri from our sun?

Slide 16 - Slide

Given
  • Speed of light in km/year = 9 460 000 000 000
  • distance proxima centauri Earth = 40 208 000 000 000

Asked
  • How many light years away is Proxima Centauri?


Formula
  • -

Calculation
40 208 000 000 000/ 9 460 000 000 000 = 4.2 light years

Slide 17 - Slide

  • The speed of light = 300 000 000 m/s — called 'c' in physics.

  • Light is used as a measure of distance (light years).

  • Astronomy studies the universe through the information in the light that reaches earth.

  • to measure the speed of light, technology had to invented that measures time in small enough intervals to be able to detect it.

  • calculations using the speed of light

Slide 18 - Slide

6.4 Reflection

Slide 19 - Slide


  • Plane mirror
  • Image
  • Virtual image — Real image
  • Types of reflection
  • The law of reflection
  •  Incident ray — reflected ray
  • Angle of reflection

Slide 20 - Slide

Slide 21 - Slide

Phet simulation
  • Search for: Phet bending Light 
  • Experiment with this independently for 5 minutes
  • What can you learn about reflection? Find out as much as you can 
  • Write down what you learned

Slide 22 - Slide

law of reflection

Slide 23 - Slide

Slide 24 - Slide

Slide 25 - Video

Homework
Read: 3.4 + 3.5
Do: Workbook exercises 6.4 (Including E)

Slide 26 - Slide

The electromagnetism practical

Slide 27 - Slide

Learning goals
  • Name the speed of light and it's name in physics
  • Explain how the speed of light us used as a unit of distance
  •  Explain how astronomers use light to study space
  •  Be able to do calculations using the speed of light

Slide 28 - Slide