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Earth and Space 6-8 / Week 12 / Wednesday
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Week 12 · Design a Solar System Model

Wednesday

Sky Deck Lab: Build and measure
// Criteria, constraints, build, measure, improve
⏱ about 20 min

Wednesday: Sky Deck Lab: Build and Measure

The Sun is a yellow paper circle taped low on the far wall. Rocket unrolls string along the hallway floor.

"Mercury at twelve," Raven reads from the plan. Rocket presses a labeled bottle cap to the floor with tape.

They work outward. Earth. Mars. Then a long walk to Jupiter. A longer one to Saturn.

"What do you notice?" Raven asks at Uranus. "We are nearly at the door, and Neptune is still three meters away."

Nova hovers over the row with her light. "Now test it," she says. "A plan is not a measurement."

Rocket runs the tape from the Sun to each cap and calls out numbers. Mars is off by four centimeters. He grins. "Found one."

Your mission

Today you build the model from your plan, then test every marker by measuring from the Sun.

The standards say a solution needs to be tested and then modified on the basis of the test results. Models of all kinds are important for testing solutions.

Record the planned distance, the measured distance and the difference for each planet. Tomorrow you improve the design.

  • Your scale table from Tuesday and your Sky Log
  • A yellow paper circle or a ball for the Sun
  • Eight small markers: bottle caps, paper squares, pebbles or buttons
  • Paper tags and a pencil for labels, and tape that will not mark the floor
  • String about as long as your space, and a tape measure or ruler
Safety first
Build in a cleared hallway, room or yard away from roads. Walk, do not run, along the model.
String and tape stay on the floor, never around anyone's neck, wrists or feet.
Small markers stay away from younger children and are never put in the mouth.
Remove the tape and markers when the family tour is done so no one trips.
  1. Tape the Sun marker at one end of your space, low on the wall or flat on the floor.
  2. Lay the string from the Sun along the floor to the far end. It is the line the planets sit on.
  3. Measure from the Sun along the string to Mercury's planned distance. Tape its marker and label there.
  4. Repeat for Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, in order, each from the Sun.
  5. Step back and check criterion one: are the eight markers in the NASA order?
  6. Test criterion two: measure each marker from the Sun again with the tape and write the result.
  7. Subtract to find the difference between planned and measured for each planet. Circle any difference over 2 centimeters.
  8. Check criterion three: count the labels. Write what is missing or unclear.
PREDICT BEFORE YOU BUILD
  • Read the question.
  • Tap your answer.
Which part of the hallway will hold four markers close together?
Which marker is most likely to end up a few centimeters off?
PlanetPlanned distance (cm)Measured distance (cm)Difference (cm)Label present?
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune

Reading your test

A difference of a centimeter or two is normal with household tape and string. A difference of ten means a marker slipped or a division was wrong.

NASA's own schoolyard model makes the same point you met yesterday. In a 30 meter model only Jupiter through Neptune are even one dot wide.

If your markers are all the same size, your model shows distances truly and sizes not at all. Write that down as an honest limit.

Testing is not failing. Every circled number is a place the design can improve tomorrow.

What the lab showsTrue or false?
Measuring each marker from the Sun tests the one-scale criterion.?
A marker that is 10 centimeters off means the whole model is useless.?
Same-size markers show distances but not planet sizes.?
The eight markers should be in the NASA order.?
WHY THIS EXERCISETesting against criteria is how engineers know what to improve.
How many markers did you measure from the Sun? Type a number.
WHY THIS EXERCISEEvery criterion is checked marker by marker.
Sketch your built model as a line with the Sun and eight markers. Write the measured distance under each one.

Built and tested. Tomorrow you read planet sizes from NASA's table and improve the design.

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