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Earth and Space 6-8 / Week 09 / Sky Night
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Week 09 · Rocks Change

Sky Night

Sky Night: Family rock walk
// Energy flows, matter cycles, rocks turn into other rocks
⏱ about 20 min

Sky Night: Family Rock Walk

Saturday at dusk, the crew leads the family along the yard path with a flashlight pointed at the ground.

Rocket hands everyone a paper bag. "Loose rocks only. Path or our yard. Nothing from the flower bed."

Raven stops at a sandy one. "What do you notice? Grains like a beach. This one tells a water story."

Nova hovers at the porch. "And the Moon is up," she says. "Sky Log first, rocks second."

They sketch the Moon's shape on the step, then sort the bags under the porch light: grains, layers, crystals.

Rocket holds up a sparkly one. "Slow cooling!" Raven smiles. "Maybe." Nova hums. "Evidence, then a guess."

  1. Geologists sort rocks into three groups by how they formed: igneous, sedimentary and metamorphic.
  2. Igneous rock is melted rock that cooled. Slow cooling grows coarse crystals; fast cooling makes fine grains or glass.
  3. Sedimentary rock is layered sediment, pressed and cemented after deep burial. Metamorphic rock is older rock changed by heat and pressure without melting.
  4. The rock cycle is driven by two engines: Earth's inner heat and the Sun-powered movement of water, ice and air.
  5. Rocks do not always make the full loop, and each step can take tens of millions of years.
◇ FAMILY ROCK WALK AND MOON CHECK
Before dark, walk a path, a beach or your own yard together. Each person picks one loose rock. Nothing comes from a park or a garden bed.
Back home, sort the rocks under a lamp into grains, layers or crystals. Let the youngest person choose first and the oldest explain.
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: sort a bowl of gravel, a brick and a smooth pebble by group. Tell each rock's likely story around the loop.
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.
Rocks are picked up only when loose, from a path, a beach or your own yard. No hammering, no scratching, nothing tasted. Everyone washes hands afterward.
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 on the path or in your yard. Never cross a road or climb anything for a better rock or a better view.
The flashlight points at the ground, never at anyone's eyes.
Nothing found outside goes in your mouth. Wash your hands when you come back inside.
THINK IT THROUGH
  • Read the question.
  • Tap your answer.
A family member finds a sparkly rock with large crystals and no layers. Which story fits best?
Which two energy sources keep the rock cycle going?
Sky Night checkTrue or false?
Loose rocks may be picked up from a path or your own yard.?
Rocks may be collected in national parks.?
Layers are a clue for sedimentary rock.?
WHY THIS EXERCISEGood collectors follow the rules and leave protected places as they found them.
Draw the rock your family liked best. Beside it, draw the Moon's shape tonight or a cloud with the date.
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