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Cells and Systems 6-8 / Week 12 / Wednesday
3/6
Week 12 · Design a Growing Station

Wednesday

Windowsill Lab: Build and begin the test
// Criteria, constraints and the Cells and Systems report
⏱ about 20 min

Wednesday: Windowsill Lab: Build and Begin the Test

The kitchen table is covered in cardboard, foil and tape. Rocket holds the box while Raven smooths the foil flat.

"Shiny side in," Rocket says. "Open side to the window. Jar in the middle."

"Measure first," Raven reminds him. "What do you notice if we build and forget the starting numbers?"

"Then we cannot tell if anything changed." Rocket grabs the ruler. "Tallest sprout, station jar: six centimeters. Control jar: six and a half."

Nova hovers above the box, checking the foil does not bounce light into anyone's eyes. "Angle it down toward the sprouts," she says.

Rocket tilts the box. The foil glows softly on the shaded side of the jar. "Day zero," he says. "Test begins."

Your mission

Today you build your station, set up the control jar and record day zero measurements for both.

The numbers you write today are the starting line. Every later measurement is compared with them.

  • Your two watered sprout jars: one for the station, one as the plain control
  • A cardboard box, foil, tape, dark paper, string, and a plate if you chose the turntable
  • A ruler marked in centimeters and your Windowsill Log
  • A hand lens or phone camera zoom
  • Scissors, used only by a grown-up
Safety first
A grown-up does all cutting of cardboard. Foil edges can be sharp, so fold them over.
Never aim foil or a mirror so that sunlight bounces into anyone's eyes. Angle reflectors down toward the sprouts.
Jars stay on the sill or table, away from the edge. Sprouts and jar water are lab materials, never tasted.
Wash your hands after the lab.
  1. Choose which jar goes in the station. Flip a coin if the two jars look alike. The other jar is the control.
  2. Measure the tallest sprout in each jar from seed to tip. Count the leaves on it. Record both as day zero.
  3. Record each jar's leaf color and whether its tallest stem is upright, leaning a little or leaning a lot.
  4. Build your station. A grown-up cuts the box. Line it with foil, shiny side in, and fold every edge.
  5. Place the station jar inside and set the box on the sill with the open side facing the window.
  6. Leave the control jar in its usual spot, with nothing changed. Check both paper towels are damp.
  7. Set a daily reminder: measure both jars at the same time each day, and turn the jar if you chose design B.
DayStation: tallest (cm)Station: leavesStation: colorStation: upright?Control: tallest (cm)Control: leavesControl: colorControl: upright?
0 (today)
1
2
3
4
SET UP A FAIR TEST
  • Read the question.
  • Tap your answer.
Why do you measure both jars today, before the test starts?
Your station jar gets foil light and daily turning. What should happen to the control jar?

Reading the setup

Models of all kinds are important for testing solutions. Your station is a model being tested against a control.

There are systematic processes for judging solutions by how well they meet the criteria and constraints. Your table is that process.

Height gained is the day 4 height minus the day 0 height. Leaf color and upright stems are recorded in words, the same words every day.

Check the constraints too. Does the station fit the space? Did you use only home materials and window light? Write yes or no.

What the lab showsTrue or false?
Day zero measurements give every later measurement something to compare with.?
The control jar is changed in the same way as the station.?
Height gained means the final height minus the starting height.?
Constraints are checked as well as criteria.?
WHY THIS EXERCISEA systematic process means every criterion and constraint is checked the same way for both jars.
How many days of measurements, counting day zero, does your table hold? Type a number.
WHY THIS EXERCISEKnowing the length of the test tells you when the comparison is complete.
Draw your finished station on the sill with the window, the foil, the jar and the control jar in its place.

Solid build. Tomorrow you read your first days of data against the criteria, the way engineers judge a design.

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