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Earth and Space 6-8 / Week 01 / Wednesday
3/6
Week 01 · Day and Night

Wednesday

Sky Deck Lab: Lamp and ball
// We ride a spinning Earth
⏱ about 20 min

Wednesday: Sky Deck Lab: Lamp and Ball

Rocket pulls the curtains and sets a lamp in the middle of the room. "The Sun. Do not touch the bulb."

Raven presses a small sticker onto a ball. "This is home. Right here on the Sky Deck."

Nova dims her own light so the lamp is the only Sun. "Predict first," she says. "Where will sunrise happen for the sticker?"

Rocket turns the ball fast. "Everywhere at once!" The sticker blurs.

"Slow down," Raven laughs. "What do you notice if you turn it one notch at a time?"

Rocket tries again, slowly. The sticker creeps from shadow into light. "Oh. It comes into the light on one edge. That edge is east."

Nova hums. "Now write down what you saw."

Your mission

Today you build the first Sky Deck model. A lamp stands for the Sun. A ball stands for Earth. A sticker stands for your home.

A model is not the real thing. It helps you explain what you see from the porch step by showing what Earth is doing.

You will turn the ball slowly and watch the sticker pass through sunrise, noon, sunset and midnight.

  • A lamp or a flashlight, set on a table or held by a grown-up
  • A ball of any kind for Earth, and a small sticker or a dot of tape for your home
  • A pencil or skewer to hold the ball, or just your hands
  • A room you can make dim, and your Sky Log
Safety first
Use a flashlight or an LED lamp. Never touch a lit bulb and keep paper and cloth away from it.
Never shine the flashlight into anyone's eyes, including your own.
Keep the room clear so nobody trips in the dim light. A grown-up handles any plug.
The lamp is the only Sun in this course. Never look at the real Sun.
  1. Set the lamp on a table in the middle of the room. Dim the other lights.
  2. Put a sticker on the ball. This is your home. Hold the ball about two steps from the lamp.
  3. Turn the ball so the sticker is in the dark, facing away from the lamp. This is midnight.
  4. Turn the ball slowly toward the east. Stop when the sticker just reaches the light. This is sunrise.
  5. Keep turning until the sticker faces the lamp most directly. This is noon.
  6. Turn until the sticker just leaves the light. This is sunset. Keep turning back to midnight.
  7. Repeat the whole turn once more, slowly, and fill in the data table below.
PREDICT BEFORE YOU TURN
  • Read the question.
  • Tap your answer.
At the moment of sunrise, where is the sticker?
If you turn the ball toward the east, on which side does the sticker first see the lamp?
Sticker positionTime of day it stands forWhat the sticker seesReal sky match (1 to 5)
Just entering the light
Facing the lamp most directly
Just leaving the light
Facing away from the lamp

Reading the model

In the model, the lamp never moved. Only the ball turned. Yet the sticker saw the lamp rise on one side and set on the other.

That is exactly what happens to us. The Sun stays put. We turn toward it in the morning and away from it at night.

The model also shows the frame of reference. If you were a tiny person on the sticker, the ball would feel still.

Everything near you turns with you, so there is nothing nearby to compare against. Only the lamp seems to move.

A good scientist also says what a model gets wrong. The real Sun is far bigger and far farther away than any lamp.

What the model showsTrue or false?
The lamp moved around the ball to make sunrise and sunset.?
The sticker entered the light on its east side.?
A tiny person on the sticker would feel the ball turning.?
The model shows that half the ball is always lit.?
WHY THIS EXERCISEThe standard asks you to use a model to explain the pattern of day and night.
How many full turns of the ball make one day for the sticker? Type a number.
WHY THIS EXERCISEOne turn of Earth on its axis is the cause of one cycle of day and night.
Sketch the lamp and the ball from above. Mark the sticker at sunrise, noon, sunset and midnight with an arrow for the turn.

A model built and tested. Tomorrow you read a real NASA table of how long a day lasts on other worlds.

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