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Bike Shop 3-5 / Week 09 / Tuesday
2/6
Week 09 · Be Seen

Tuesday

Smooth and rough
// Light, reflectors and bright colors
⏱ about 15 min

Tuesday: Smooth and Rough

Rocket shines a flashlight at a shiny spoon on the bench. A bright spot lands on the wall.

Then he shines it at his wool hat. No bright spot appears.

"Why is the spoon so different?" he asks.

Raven runs a finger over each one. "What do you notice about the surfaces?"

Nova hovers over the hat. "One is smooth. One is rough," she says.

Two ways to reflect

Smooth, shiny surfaces like glass, still water and polished metal reflect like a mirror.

Light bounces off them all in the same direction.

A very smooth mirror reflects almost all the light that hits it.

Rough surfaces scatter the light in all directions.

That scattered light is how we see most things around us.

SurfaceSmooth or rough?Where the light goes
mirrorsmoothbounces all one way
still watersmoothbounces all one way
wool hatroughscatters in all directions
paperroughscatters in all directions
MIRROR OR SCATTER?
  • Read the question.
  • Tap your answer.
Light hits a mirror. Where does it go?
Light hits a rough wool hat. Where does it go?
Why did the spoon make a bright spot on the wall?
A smooth surface reflects light all one ____.
A rough surface ____ light in all directions.
Try it
Gather a spoon, a sheet of foil and a piece of cloth.
In a dim room, a grown-up shines a flashlight at each one.
Point the light at the object, never at anyone's face.
Look for a bright spot on the wall or table.
Safety first
Never shine a flashlight into anyone's eyes.
Use a small flashlight, not a laser.
No flashlight? Look at each object near a sunny window.
Do not look at the Sun.
Object I testedSmooth or rough?Bright spot? (yes or no)
spoon
foil
cloth
StatementTrue or false?
Still water can reflect like a mirror.?
Rough paper reflects light all one way.?
We see most things by scattered light.?
WHY THIS EXERCISESmooth surfaces mirror light. Rough ones scatter it.
In your Bike Shop Notebook, draw light hitting a mirror and light hitting a hat. Use arrows.

Shiny science! Tomorrow we test which colors are easiest to spot.

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