properties of light

P4 Properties of light

Light travels in a straight line

light coming out from its source travels in a straight line,

​Light helps us to see things.

Light travels in a straight line.

Light can be reflected from surfaces, such as mirrors, which are used in periscope.

Light can pass through transparent materials and partially pass through translucent materials

Light cannot pass through opaque materials

If the light is blocked, it creates shadows.

Light can be reflected from surfaces

Many objects around us are not sources of light ,however we are able to see them because they reflect light into our eyes

Light cannot bend over the wall to enable us to see the objects behind the wall

Based on this experiment we know that we can see object in straight line

Light reflected from different surfaces

• 1. A smooth surface reflects light in the same direction

• 2. A rough surface reflects light in different directions

Reflected of light from a mirror

Based on this picture we know the process:

Object reflects light from the lamp onto the mirror then the mirror reflect the light into our eyes

Multiple Choice

What happens to light when it is refracted?

• it hits a surface and bounces off

• it is absorbed by an object

• it passes through different medium

• it disappears when it is bright

The mirror allows us to see parts of the shop that are not easily seen otherwise

Periscope

A periscope allows us to see objects that cannot be seen directly from where we are

Periscope

• 1. Light from an objects strikes the top mirror

• 2. The light is then reflected down the periscope tube

• 3. the light strikes another mirror at the bottom. The light is then reflected into observer's eyes

It is the bending of light as it moves from one material to another like air to water. When it goes through water, which is denser than air, it moves slower. When it happens, the light is refracted making an object seems to be divided into 2 parts.

Refraction

Translucent Object

is the object that allow only some light to pass through them

For examples: some paper, plastic cloth , frosted glass

Transparent Object

is the object that allow light to pass through them, so we can see it clearly

For examples: glass, some plastics appear clear

Opaque Object

is the object are not allow light to pass through them at all

For examples: wood, metal, some plastics, cardboard, and clay

Shadows and sizes of shadows

• 1. Shadows formed when tin is placed upright

• 2. Shadows formed when tin is placed lying down

• 3. Shadows formed when light source is close to object

• 4. Shadows formed when light source is far from object

Shadows

is formed because light travels in a straight line, it cannot bend to move around objects.

Multiple Choice

We are able to see objects around us because they ..... light into our eyes

• transfer

• share

• reflect

• erase

Multiple Choice

light travels from a ...... and travels in a straight line

• source

• reflect

• non straight

Multiple Choice

A ..... surface reflect light in the same direction

• rough

• thick

• thin

• smooth

Multiple Choice

A rough surface reflect light in ..... directions

• same

• different

• right

• left

Multiple Choice

Why is the reason based on this picture Jos is able to see Sue?

• Because sue is in front of Jo

• Because there is big mirror

• because Sue body's reflects light from the lamp onto mirror and then that mirror reflect the light into Joe's eyes

• because Sue body's cannot reflects light from the lamp onto mirror and then Sue's voice comes into Joe's ear

Multiple Choice

A periscope allow us to see objects that ............. be seen directly from where we are

• can

• can not

• both of them

• none of them

Multiple Choice

the object that allow some light to pass through them we call it .....for examples paper, plastic, cloth, frosted glass

• opaque

• transparent

• translucent