3.8: Natural events and humans influence ecosystems: human activity…

Rocks and Erosion: How Land Changes Shape Grade 4

Why some rocks scratch and some fizz, how a trickle of water carves a canyon, what keeps a hillside in place, and how a boulder ends up as sand. Four hands-on lessons on rocks, weathering and erosion.

• Are all rocks the same? 50–60 min

  Students sort a set of rocks by what they can see, then test them like geologists with a scratch test, a streak test and a drop of vinegar. They use their results to sort the rocks again and back up a claim about which rock is limestone.

• Can water carve a canyon? 50–60 min

  Students build a stream table in a foil pan of damp sand, let a steady trickle of 'rain' run down a gentle slope and a steep one, and measure the channel each time. They use the measurements to explain how running water carves valleys and canyons and drops sand where it slows down.

• What protects a hillside from washing away? 55–60 min

  Teams build model hillsides of soil in foil pans, some bare, some covered with leaves or mulch and some held together with string 'roots', then make it rain on each one the same way. They measure the runoff and the mud it carries, and recommend the best way to protect a real slope.

• How do rocks become sand? 50–60 min, plus a 5 min check the next day

  Students shake sugar cubes in a jar for set times and measure how their sharp corners wear into rounded grains, then watch frozen water push a plug out of a sealed straw. They explain how tumbling and ice break rock into smaller and smaller pieces, all the way down to sand.

Earth Day Investigations: Make Your School Better Grades 4–6

Four hands-on investigations into the school's own garbage, shade, water and electricity. Each one ends with students taking a real, evidence-based recommendation to the principal or caretaker.

• What's in our garbage? 50–60 min

  Teams wear gloves to sort one day of classroom waste into landfill, recycling and compost, weigh each pile and graph the results. They use the numbers to recommend one change to the principal or caretaker.

• Where would a new tree help most? 50–60 min

  Teams measure air and ground temperature in sun and shade, on grass and on pavement, to see how much shade cools the schoolyard. They use their numbers to recommend where the school should plant a new tree.

• How much water does a dripping tap waste? 45–60 min

  The class counts drips per minute from a slow-dripping tap, catches and measures the water, then scales it up to a day and a year. Students use the math to recommend how the school should report and fix drips.

• Is our classroom wasting electricity? 45–60 min

  Students audit their classroom's lights and devices, check which are left on when nobody needs them, and read wattage labels to estimate the energy wasted in a school year. They finish with a poster or letter recommending one easy change.

Printable practice for 3.8

• Earth Day Investigations: Make Your School Better workbook included with the unit

  4 English-support pages, 4 practice pages, 4 readings, 1 word wall, 1 unit review, 1 unit test, with answer keys.

• Our Changing Planet: Resources and Human Impact workbook included with the unit

  1 word wall, 1 English-support page, 1 practice page, 1 reading, 1 unit review, 1 unit test, with answer keys.

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