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Earth and Space 6-8 / Week 10 / Sky Night
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Week 10 · Reading the Layers

Sky Night

Sky Night: Putting events in order
// Oldest at the bottom, youngest on top
⏱ about 20 min

Sky Night: Putting Events in Order

Saturday evening, the crew sets the sediment bottle on the porch rail beside the Sky Log.

"Family game," Rocket announces. "Everyone names an event from our family. No dates allowed."

Raven writes them on cards: the move to this house, the day the tree fell, the first bike ride, the puppy.

"Now put them in order," she says. "What do you notice? We can do it without a single number."

Nova hovers above the cards, her light on the row. "That is relative dating," she says. "Geologists do the same with layers."

Rocket glances up. "And the Moon is out." Nova hums. "Sketch it. Then finish the order."

  1. Sediment settles with the largest and heaviest particles first, making layers called strata.
  2. Superposition: in an undisturbed stack, the bottom bed is older than any bed above it. Tilted beds were moved after they formed.
  3. A feature that cuts across layers is younger than the layers. A fragment inside a rock is older than the rock.
  4. An unconformity is a gap in the record, like the tilted and flat layers in the Grand Canyon wall.
  5. Fossils change through time, so layers with the same fossils are the same age. Strata and fossils give relative dates, not years.
◇ FAMILY ORDER GAME AND MOON CHECK
Each family member names one family event. Write each on a card with no dates. Together, arrange the cards from oldest to youngest.
Talk about the evidence you used: who was there, what came before, what came after. Then add the years if anyone knows them.
If the sky is clear, sketch the Moon's shape from your known spot for the Moon log. If it is cloudy, write "cloudy" and the date.
Cloudy-night backup: shake the sediment bottle together over the sink, time the layers, and tell its story using Tuesday's rules.
For a grown-up
Night observation happens only with you, from the yard, porch or a window, in a known spot. Bring warm clothes and a flashlight for the path.
If the bottle is shaken again, please tighten the lid first and shake over a sink or outdoors.
The recap facts come from the United States Geological Survey at pubs.usgs.gov and the open textbook Physical Geology on geo.libretexts.org.
Safety first
Stay in your known spot. Never cross a road or climb anything for a better view of the Moon.
The flashlight points at the ground, never at anyone's eyes.
Nothing from the bottle is tasted. Wash your hands afterward.
THINK IT THROUGH
  • Read the question.
  • Tap your answer.
Your family put events in order without any dates. What kind of dating is that?
In the sediment bottle, which layer formed first?
Sky Night checkTrue or false?
Layers with the same fossils are the same age.?
Rock layers tell exactly how many years passed.?
The bottom layer of an undisturbed stack is the oldest.?
WHY THIS EXERCISEOrder is what layers give. Years come from other tools, next week.
Draw your family's event cards in order as a stack of layers, oldest at the bottom. Add tonight's Moon shape in the corner.
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