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Science Launch G5 / Week 12 / Wednesday
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Week 12 · Stars and Shadows

Wednesday

Investigation: Shadow tracker
// Our star, our shadows and the turning sky
⏱ about 15 min

Wednesday: Investigation: Shadow tracker

Rocket tapes a pencil upright onto a square of cardboard. He sets it in a sunny spot on the porch.

"The Sun moves across the sky every day," he says. "So the shadow should move too."

Raven draws an arrow on the cardboard pointing north. "And we mark the shadow three times," she says. "Morning, midday and afternoon."

Nova hovers beside the pencil. "Remember the rule," she says. "Look at the shadow, never at the Sun."

Rocket traces the first shadow carefully. It stretches long across the cardboard.

What you need

  • A pencil and a square of stiff cardboard
  • Tape or a small ball of modeling clay to hold the pencil upright
  • A marker and a ruler
  • A sunny spot where the cardboard will not be moved all day
Safety first
Never look at the Sun. Look only down at the shadow.
Choose a safe spot with a grown-up, away from streets and steps.
Wear a hat and sunscreen if you are outside for long.

Steps

  1. Stand the pencil upright in the middle of the cardboard.
  2. Put the cardboard in a sunny spot. Do not move it again.
  3. In the morning, trace the pencil's shadow and write the time.
  4. Make your prediction below.
  5. Around midday, trace the shadow again and write the time.
  6. In the afternoon, trace it a third time.
  7. Measure each shadow with a ruler.
MAKE A PREDICTION
  • Read the question.
  • Tap your answer.
When do you predict the shadow will be shortest?
TimeShadow length (centimeters)Which way did it point?
Morning
Midday
Afternoon

When the Sun is low in the sky, shadows are longer. When the Sun is higher, shadows are shorter.

Around midday the Sun is highest, so shadows are shortest.

The direction of the shadow changes too, because the Sun's position in the sky changes during the day.

Is a shadow longer when the Sun is low or high in the sky? Type one word.
WHY THIS EXERCISEA low Sun shines from the side and stretches shadows, while a high Sun makes them short.

What your shadows showed

Look at your three shadow tracings.

Compare their lengths and the way they point.

Both changed because the Sun's position in the sky changed during the day.

SHADOW THINKING
  • Read the question.
  • Tap your answer.
When the Sun is low in the sky, shadows are...
Why did we never move the cardboard?
StatementTrue or false?
Shadows are shortest around midday.?
You should look at the Sun to check its position.?
A shadow's direction changes during the day.?
WHY THIS EXERCISEShadows change length and direction. Never look at the Sun.

You turned a pencil into a science tool. Tomorrow we will learn why the Sun seems to move.

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