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Earth and Space 6-8 / Week 03 / Sky Night
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Week 03 · Eclipses

Sky Night

Sky Night: Predict and model
// When the shadows line up
⏱ about 20 min

Sky Night: Predict and Model

Saturday night, the crew gathers in the yard with the Moon log and a flashlight pointed at the grass.

"Before we look up," Raven says, "predict. What phase should it be tonight?"

Rocket flips back a week. "Waxing gibbous last Saturday. Then full. So tonight, waning gibbous."

They look up. The Moon is a little past full, lit on one side with a thin dark edge. "Waning gibbous," Rocket says. "Called it."

Nova hovers low, her light off. "What do you notice about last week's full Moon?" she asks. "No eclipse."

"Because it passed above or below Earth's shadow," Raven says. "Most months do."

Rocket sketches the Moon. "Night eight. And now the eclipse game."

  1. An eclipse happens when Earth or the Moon enters the shadow of the other. The name says what gets darker.
  2. A solar eclipse is the Moon's shadow on Earth, at new Moon. A lunar eclipse is Earth's shadow on the Moon, at full Moon.
  3. The Moon's orbit is tilted about 5 degrees, so most months the shadows miss. Eclipse season comes twice a year.
  4. A total solar eclipse lasts at most about 7 minutes along a narrow path. A total lunar eclipse can last 1 hour 40 minutes for half of Earth.
  5. Never look at the Sun, eclipse or not. The Moon is safe to look at, with a grown-up.
◇ FAMILY MOON LOG AND ECLIPSE GAME
Before going out, each person predicts tonight's phase from last week's Moon log. Then go out together and check.
Everyone sketches the Moon in a circle, shading the dark part. Write the date and the phase name.
Back indoors, play the eclipse game: one person is the lamp, one holds Earth, one holds the Moon on a pencil.
The Moon holder orbits Earth. The others call "solar", "lunar" or "miss" for each pass. Swap roles.
Cloudy night backup: skip the Moon look, play the eclipse game and sketch the phase the Moon should be tonight.
For a grown-up
Night observation happens only with you, from the yard, a porch or a window, in a known spot, with warm clothes.
A flashlight lights the path only and is never shone into anyone's eyes. Never cross a road or climb for a better view.
The recap facts come from NASA at science.nasa.gov and spaceplace.nasa.gov, and from OpenStax Astronomy at openstax.org.
Safety first
Go outside at night only with a grown-up, to a spot you know well.
Keep the flashlight pointed at the ground. Never shine it at anyone's eyes.
Indoors, never look straight into the lamp. Watch the shadows instead.
THINK IT THROUGH
  • Read the question.
  • Tap your answer.
Last Saturday was waxing gibbous. What phase should tonight be, a week later?
In the eclipse game, the Moon passes behind Earth but a little above the line. What do you call?
Sky Night checkTrue or false?
A full Moon with no eclipse is normal, because the Moon usually passes above or below Earth's shadow.?
It is safe to look at the Moon during a lunar eclipse.?
A solar eclipse can happen at full Moon.?
WHY THIS EXERCISEPredicting tonight's phase and explaining the missing eclipse are both uses of the same model.
Draw tonight's Moon in a circle, shading the dark part. Add the date and the phase name for the Moon log.
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