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Astronomy Year / Week 09 / Wednesday
3/6
Week 09 · Star Colors and Brightness

Wednesday

Near and far
// Hot stars, cool stars, near and far
⏱ about 15 min

Wednesday: Near and far

Rocket holds a small flashlight. Raven stands far away with a big one.

"Mine looks brighter!" Rocket says. "But Raven's light is stronger."

Raven asks, "What do you notice about distance?"

Nova hums. "Hint: walk closer and see what changes."

Brightness depends on two things

How bright a star looks depends on two things.

One: how much light the star really gives off.

Two: how far away the star is.

A dim light up close can outshine a strong light far away.

Try it
Use two flashlights in a dark room.
Your grown-up stands far away with one.
You hold the other one near you.
Which looks brighter? Then trade places.
Safety first
Point flashlights at a wall, not at eyes.
Clear the floor so you do not trip.
BRIGHTNESS CHECK
  • Read the question.
  • Tap your answer.
A light moves farther away. How does it look?
Two stars give off the same light. One is much closer. Which looks brighter?
Bright ideaTrue or false?
Distance changes how bright a light looks.?
A star that looks dim must give off little light.?
WHY THIS EXERCISEBrightness depends on light and distance together.

Flashlight results

TestWhich looked brighter?
Small light near, big light farOften the small light near
Same light, near and farThe near one

Your results may be different.

Write down what you really saw.

NEAR AND FAR THINKING
  • Read the question.
  • Tap your answer.
A strong light is very far away. How can it look?
Brightness depends on a star's light and what else?
Your test came out a little different. What do you do?
A dim star looks faint. Does it surely give off little light?
RUN THE FLASHLIGHT TEST
  • Tap a card.
  • Then tap its spot.
1First
2Next
3Then
4Last
Draw a small light close by and a big light far away.

You tested brightness like a scientist! Tomorrow we look at our brightest star.

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