Humans have had a huge effect on the environment by producing and releasing pollutants. Pollution leads to a variety of issues. Some of the better-known pollutants include greenhouse gases, which are the main cause of global warming; acid-producing air pollutants that result in acid rain; and persistent toxic chemicals, which can result in the death of the top predators in ecosystems.
In 1962, Rachel Carson published the book Silent Spring, in which she warned of the dangers of overusing pesticides and the potential environmental problems caused by the industrial revolution. Less than a decade later the impacts of these chemicals became apparent as some top predatory bird populations began to decline due to the toxins reducing the success rate of eggs hatching.
In this demo, containers represent organisms in a food chain and beads represent a water-borne toxin to which the organisms are exposed.