Medium⏱ time1.5 hr + days$ cost8

Green Roof Model

Compare a planted roof to a bare one for cooling and rainwater absorption.

Result first

The build

Step 01

One bare, one with soil and plants.

Step 02

Light both equally and measure inside temp.

Step 03

Pour equal water and catch runoff.

Step 04

Note temperature and runoff differences.

Working Principle

The planted roof shades and insulates the building and its soil soaks up rain, so it stays cooler and sheds less runoff than the bare roof.

The science behind it

Green roofs cut urban heat and stormwater runoff — a city-cooling strategy you can measure here.

Take it further

Sand, gravel and charcoal layers visibly clear muddy water — a model of natural and plant filtration.

Foil and plastic wrap turn a pizza box into an oven that melts chocolate with only sunlight.

Blades drive a small generator to light an LED, modelling clean wind power.