Pollutant
A Pollutant is something added to soil, water, or air that harms living things.
A drop of ink falls into a clear glass of water. The ink spreads out, turning the water dark. Fish and plants in that water could not survive. That ink is a pollutant — something added that does not belong and causes harm.
Explaining pollutant by grade level
Some things hurt plants when they get in the dirt. If you pour soap water on a plant, it may stop growing. The soap stays in the soil. It makes it hard for roots to do their job.
Projects that explore pollutant
Detergent enters soil through wastewater and harms the living things that depend on it. In this project, pea plants watered with soapy water may weigh less than plants given plain water. That mass difference shows what a common household pollutant does to plant growth.
Antifreeze leaks into irrigation water and becomes a pollutant that harms living things. This project grows radishes in two concentrations of propylene glycol to measure the damage. Higher concentrations cause more harm, showing how dose determines the impact on plants.
Rain washes road deicers into nearby soil, where they act as pollutants that harm living things. This project tests rock salt, calcium chloride, and magnesium sulfate on radishes. The deicer groups lost nearly every plant, showing how chemical runoff added to soil can devastate what grows there.
Motor oil added to soil is a pollutant that poisons the ground and stops seeds from growing. This project tests whether oil-absorbing polymers can clean contaminated soil well enough for green beans to sprout. The results show whether removing the pollutant restores conditions for living things.