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Weather Lab 6-8 / Week 08 / Wednesday
3/6
Week 08 · Air Masses and Fronts

Wednesday

Station Lab: Air masses in a box
// Where weather changes come from
⏱ about 20 min

Wednesday: Station Lab: Air Masses in a Box

A clear plastic box sits on the lab bench with a stiff card wedged across the middle like a wall.

"Cold on this side, warm on that side," Rocket says. "Then I pull the wall and we see a front."

Raven adds blue coloring to the cold water and red to the warm. "What do you notice before we start?"

"Nothing," Rocket says. "They cannot touch yet."

Nova hovers at eye level with the box. "Predict first," she says. "Which color ends up on the bottom?"

Rocket thinks about the heavy cold air sliding under warm air. "Blue," he says, and lifts the card.

Your mission

Air is hard to see, so you will use water as a stand-in. Cold water and warm water behave like cold air and warm air at a front.

You will predict what happens when they meet, then watch and record it.

  • A clear plastic box or large clear container, at least as long as a shoebox
  • A stiff card or plastic lid that fits tightly across the middle as a divider
  • Cold tap water with a few ice cubes, and warm tap water that feels like a warm bath
  • Blue and red food coloring
  • A tray or towel to catch spills
  • Your weather log and a pencil
Safety first
A grown-up fills the warm side. Use warm tap water only, never water from a kettle or stove.
Work over a tray or a sink. Wipe up spills right away so the floor is not slippery.
The colored water is for watching, not tasting. Wash hands when you finish.
Food coloring can stain. Wear old clothes and keep it off counters.
  1. Set the divider in the middle of the box. Press it so water cannot leak past.
  2. Fill one side with cold water and add blue coloring. Take out the ice cubes once the water is cold.
  3. Have a grown-up fill the other side with warm water to the same level, then add red coloring.
  4. Write your prediction: which color will slide underneath when they meet?
  5. Lift the divider straight up in one smooth move. Watch from the side for one full minute.
  6. Sketch what you see at 10 seconds, 30 seconds and 60 seconds.
  7. Wait five minutes and look again. Describe the final pattern.
TimeWhere is the blue?Where is the red?Where do they meet?
10 seconds
30 seconds
60 seconds
5 minutes
PREDICT AND EXPLAIN
  • Read the question.
  • Tap your answer.
Before you lift the divider: which water do you predict will slide along the bottom?
In the box, the sloping line where blue meets red is a model of what?

What the box shows

In the box, the water that is colder and heavier moves along the bottom, and the warmer water rides over it.

A real front is also a boundary between two air masses of different density, and the cooler air is the denser one. Clouds and precipitation develop along the front.

A box of water is a model. It leaves out wind, rain and the size of a real system. But it shows the key idea: the two bodies do not simply mix.

What the lab showsTrue or false?
Cold and warm water mixed instantly into one purple color.?
The boundary between the two colors models a front.?
A front is a boundary between two air masses of different density.?
A box of water is a perfect copy of a real weather system.?
WHY THIS EXERCISEKnowing what a model leaves out is as important as knowing what it shows.
Draw your box at 60 seconds as a side view. Label the cold side, the warm side and the sloping front between them.

Great lab work. Tomorrow you read a day of real front weather and learn what "chance of rain" means.

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