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Unit 4 · Light Energy1 / 14
MISSION 3

Light Explorer

How do we see? Can light pass through?
Welcome back, Explorer! Today we find out how light helps us see,
and which materials let light pass through.
Explorer's name:
How to play
1. Read what Glow says on each page.
2. Do the mission under it.
3. Win 3 badges. Colour each badge when you win it!
Eye Expert
Material Detective
Light Professor
Light Explorer · Mission 32 / 14

Remember Mission 2?

Warm-up time! Show me what you remember about light and shadows.
Fill in the blank.

Light travels in a line away from its source.

Circle the correct words.
  1. A shadow forms when light passes throughis blocked.
  2. At midday, my shadow is shortlong.
Ploy holds a ball between a lamp and a wall. She moves the lamp closer to the ball. What happens to the shadow?
Why is the shadow of a red ball dark, not red?
Light Explorer · Mission 33 / 14

The Moon mystery

Remember your guess about the Moon? The Moon has no light of its own. Sunlight hits the Moon and bounces off it. This bouncing is called reflection.
SunMoonGlow's friend
Was your guess right? Circle the correct words.
  1. The Moon reflectsgives out light.
  2. Moonlight really comes from the MoonSun.
Ray drawing. Use a ruler. Draw rays with arrows to show how light helps Glow's friend see the Moon.
At night, we cannot see the Sun. So why can we still see the Moon?
Light Explorer · Mission 34 / 14

How do we see a source of light?

A source of light gives out its own light. Its light travels in straight lines. When some of that light reaches us, we can see the source.
Ben looks at a lamp, which is a source of light. Which picture shows how Ben sees the lamp? Circle it.
A
B
C
D
Fill in the blank.

We see a lamp because its light goes into our .

Mali closes her eyes and faces a bright lamp. Can she see the lamp? Explain.
Glow says, "My eyes send out light so I can see." Is Glow right? Why?
Light Explorer · Mission 35 / 14

Seeing things that are not sources

Most things are not sources of light. We see them because light from a source hits them and reflects off them. Some of that light comes to us.
How does Glow see the book? Write 1, 2 or 3 to put the steps in order.
The light reflects off the book.
The reflected light goes into Glow's eyes.
The lamp gives out light.
Ray drawing. Draw rays with arrows to show how the girl sees the parrot.
Fill in the blank.

Light bounces off the parrot. We say the parrot light.

Light Explorer · Mission 36 / 14

Source or not?

Some things give out their own light. Other things only reflect light. Careful! Shiny things can look bright, but that does not make them sources.
Sort them. Write each thing in the correct column.
a mirror · the Sun · the Moon · a firefly · a white wall · a candle flame · a disco ball · a TV that is on
Gives out its own lightOnly reflects light
At a party, a disco ball sparkles. Ploy says it is a source of light. Is she right? Explain.
Write one thing in your home that reflects light but is not a source.
Light Explorer · Mission 37 / 14

Can we see in the dark?

To see an object, we need light and our eyes. Light has to travel from the object to us. No light, no seeing!
Science story. Long ago, many people believed that our eyes sent out light to see things. About 1,000 years ago, a scientist called Ibn al-Haytham showed that light travels into our eyes.
Circle the correct word.

In a room with no light at all, we cancannot see a red ball.

Glow switches off every light in a room with no windows. Why can't he see his book?
How does a dark room show that Ibn al-Haytham was right?
Light Explorer · Mission 38 / 14

Mirror or board?

Every object reflects some light. Smooth, shiny surfaces like mirrors send the light off neatly in one direction. Rough, dull surfaces spread the light out in many directions.
wallSharif: mirror
wallMajid: wooden board
Sharif shines a torch at a mirror. Majid shines a torch at a wooden board. Who sees a bright spot of light on the wall?

SharifMajid sees a bright spot.

Circle the three things that reflect light best.
a wooden boarda mirrorkitchen foila towela carpeta shiny spoon
Why can you see yourself in a mirror but not in a wooden door?
Light Explorer · Mission 39 / 14

Can light pass through?

Transparent materials let almost all light through. Translucent materials let only some light through. Opaque materials let no light through.
1
tracing paper
2
wood
3
clear glass
Label each material. Use the words in the box.
opaque · transparent · translucent

1   2   3

Match each word to what it means. Write the letter.
1.transparenta. Some light passes through. Things look blurry.
2.translucentb. Light bounces off it.
3.opaquec. We can see clearly through it.
4.reflects lightd. No light passes through it.
Glow shines a torch at tracing paper. What will he see on the other side?
Light Explorer · Mission 310 / 14

Sort the materials

Every material lets light through in its own way. Sort these like a scientist. Then think about their shadows!
Write each material in the correct column.
frosted glass · cardboard · window glass · wax paper · a metal spoon · clear plastic · a wooden door · clean water · tracing paper
TransparentTranslucentOpaque
A torch shines on each object. What kind of shadow does it make? Circle one answer.
1.a wooden blockdarkpalealmost none
2.a clear glassdarkpalealmost none
3.tracing paperdarkpalealmost none
Bathroom windows are often made of frosted glass. Why?
Light Explorer · Mission 311 / 14

Eye Expert

Careful, Explorer! Some of these are tricks. Get 7 or more right to win your first badge!
Circle True or False.
1.We see the Moon because it gives out its own light.TrueFalse
2.A mirror is not a source of light.TrueFalse
3.Light from a lamp travels into our eyes.TrueFalse
4.Our eyes send out light so that we can see.TrueFalse
5.Tracing paper is transparent.TrueFalse
6.Frosted glass makes a paler shadow than wood.TrueFalse
7.A disco ball is a source of light.TrueFalse
8.We see a book because light reflects off it into our eyes.TrueFalse
Eye Expert
My score: / 8
7 or more? Colour your badge on page 1!
Light Explorer · Mission 312 / 14

Material Detective

Detective time! Solve the mystery words. Then choose the best material for each job.
Who am I? Write the answer.
1.“You can see yourself in me.”
2.“Things look blurry through me.”
3.“I shine at night with the Sun's light.”
4.“I let no light through at all.”
Choose the best material for each job. Use the words in the box.
thin paper · glass · thick cloth
1.a fish tank window
2.curtains for a dark bedroom
3.a lampshade for soft light
Material Detective
All correct?
Colour your badge on page 1!
Light Explorer · Mission 313 / 14

Book Challenge

These are the big questions you will meet at school. Answer in full sentences to win your third badge!
How do we see a source of light?
How do we see non-sources of light?
What is the difference between transparent, translucent and opaque materials? Give an example of each.
Light Professor
Finished? Colour your last badge on page 1!
Light Explorer · Mission 314 / 14

Mixed challenge

Last page! Here is the boss question. Then get ready for your next mission.
Glow wants to hide a present so nobody can see it. Should he use a glass box or a cardboard box? Why?
Boss question! In this pinhole camera, the picture of the candle on the screen is upside down. Use what you know about light to explain why.
pinhole camerascreen