Science Grade 6 - Chapter 4.2 - Light

Science Grade 6 - Chapter 4.2 - Light

Science Grade 6 Revision Period

Light Waves

• Peak or crest is the top of a wavelength

• Trough is the bottom of the wave length

• The amplitude of a wave is the maximum distance between the equilibrium position of a wave and its peak or trough. 

• The wavelength is the distance between two successive crests or troughs of a wave.

Electromagnetic Waves

• Light is energy

• Light is carried by electromagnetic waves through empty space and matter.

• All the electromagnetic waves from the electromagnetic spectrum

• All light travels in straight lines.

Visible light spectrum

• The visible light spectrum is the part of the electromagnetic spectrum that humans can see.

• Violet light - most energy - Short wavelength

• Red light - least energy - long wavelength

Light and shadows

• A shadow is formed when an object reflects or absorbs light

• It is affected by the angle and distance of the light source.

Absorption, Reflection, Refraction

• Absorption - When an object absorbs light - Particles move faster - objects get warmer!

• Reflection - When light bounces off an object - a red apple looks red because it reflects mostly red light.

• Refraction - bending of light - When light moves from one material to another the speed changes, causing refraction.

Types of lenses

• Concave - Looks like a cave entrance - Thin in the middle - Light bends outwards.

• Convex - Large in the middle - Light bends inwards.

Multiple Choice

Which of the following colours on the visible light spectrum has the greatest amount of energy?

• Red

• Indigo

• Violet

• Yellow

Multiple Choice

Which of the following colours on the visible light spectrum has the least amount of energy?

• Red

• Indigo

• Violet

• Yellow

Fill in the Blanks

Multiple Choice

How would the size of the dark area change when the sun reaches position 1? Choose the answer.

• The shadow will get larger

• The shadow will get shorter

• The shadow will not change size

Multiple Select

Which statements are true about the absorption of light energy?

• Absorption is the taking in of light energy

• A substance will become cooler

• A substance will become warmer

• The absorb light will turn into thermal energy

Multiple Choice

Light rays strike the left side of the lens shown below.

Select the letter that best shows how the light rays emerge from the right side.

• A

• B

• C

• D

Multiple Select

Which of the following factors affect shadows?

• The distance of the light source from the object

• The colour of the object

• The angle of the light source

Multiple Select

Which of the following are true about this lens?

• Concave lens

• Convex lens

• Light bends inwards

• Light bends outwards

Multiple Select

Which of the following are true about this lens?

• Concave lens

• Convex lens

• Light bends inwards

• Light bends outwards