Global Systems Demonstrations

Global systems demonstrations illustrate how Earth’s processes such as climate, oceans, and ecosystems are interconnected. They emphasize the importance of seeing the planet as a set of linked systems rather than separate parts.

Demonstration	Materials	Difficulty	Safety	Summary
Bread Model of Ground Pollution	★☆☆	★☆☆	★☆☆	This experiment uses slices of bread and food coloring to simulate how pollutants seep into the ground after rainfall. Students can observe how different amounts of precipitation affect the spread and depth of pollution in porous layers.
Carbon Dioxide Greenhouse Jar	★★☆	★☆☆	★☆☆	This experiment models the greenhouse effect using jars filled with different controls and a baking soda–vinegar reaction to produce carbon dioxide. By comparing temperatures in jars with and without trapped CO2, students see how greenhouse gases can trap heat.
Greenhouse Analogy with Chocolate	★☆☆	★☆☆	★☆☆	This classroom activity models the greenhouse effect using chocolate squares instead of thermometers. By comparing how quickly chocolate melts inside and outside a transparent container under a light source or the Sun, students observe how greenhouse gases trap heat in Earth’s atmosphere.
Melting Ice and Rising Sea Levels	★☆☆	★☆☆	★☆☆	This experiment shows the difference between melting sea ice and melting land ice. Sea ice melts without raising water levels, while land ice melting adds extra water and raises sea levels.
Ocean Acidification	★★☆	★☆☆	★☆☆	By blowing air through water containing a pH indicator, students can observe how dissolved carbon dioxide lowers the pH of water, demonstrating the process of ocean acidification.
Scattering of Light with Milk	★☆☆	★☆☆	★☆☆	A flashlight shining through water mixed with milk demonstrates how scattering of shorter wavelengths makes light appear blue from the side and red-orange when viewed through the length of the liquid, simulating why the sky is blue and sunsets are red.
Sympathetic Resonance with Tuning Forks	★★☆	★☆☆	★☆☆	When one tuning fork is struck and placed near another of the same frequency, the second fork begins to vibrate without being struck.
Tragedy of the Commons Fishing Simulation	★☆☆	★☆☆	★☆☆	This classroom simulation models the “Tragedy of the Commons” using colored marshmallows (or other small items) as fish. Students compete to maximize their catch but quickly discover that overfishing leads to resource collapse, while cooperation and restraint allow the population to replenish.
Fire Tornado	★★★	★★☆	★★★	This dramatic demonstration shows how a spinning column of fire can be created using a rotating screen cylinder and a flame source. It models the dangerous fire tornadoes that occur in extreme wildfires when hot air updrafts combine with swirling winds.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff