Water Cycle
Types of Pollution
Sources of Pollution
Water Quality Tests
Effects of Pollution
100

This process occurs when liquid water changes into water vapor, often from oceans, lakes, and puddles.

What is evaporation?

100

When sulfur dioxide and nitrogen oxides mix with water vapor in the atmosphere, they form this damaging type of precipitation.

What is acid rain?

100

Smoke and ash from these non-volcanic natural events can drastically raise particulate matter levels in the air over large regions.

What are wildfires?

100

This water quality factor, measured on a scale from 0–14, determines how acidic or basic a sample is.


What is pH?

100

In the stratosphere, this gas blocks harmful UV rays.  At ground level, the same gas makes it difficult to breathe.

What is ozone?

200

Rain, snow, sleet, and hail are all forms of this stage of the water cycle.


What is precipitation?

200

This common air pollutant, released from cars and trucks, is odorless, colorless, and can prevent oxygen from binding to your blood.

What is carbon monoxide?

200

These high-flying machines emit nitrogen oxides at high altitudes, contributing to ground-level ozone formation and climate impacts.

What are airplanes?

200

This test measures how clear or cloudy water is; high readings often indicate erosion or sediment runoff.


What is turbidity?

200

This element in a nitrate molecule is needed by plants to have strong stems and a healthy green color.


What is nitrogen?

300

This step occurs when water seeps down through soil and rock layers, helping to refill aquifers.


What is percolation?

300

Farm fertilizer runoff is the main source of this water pollutant, which can trigger eutrophication when levels are too high.

What is nitrate? 

300

This fossil fuel, when burned in power plants, is a major source of sulfur dioxide and mercury pollution.


What is coal?

300

Cold water holds more of this gas than warm water, making it essential for fish, insects, and most aquatic organisms.

What is oxygen?

300

When nitrogen and phosphorus from fertilizers enter waterways, they can cause explosive growth of algae, also known as this phenomenon.

What is eutrophication?

400

This term refers to water flowing over Earth’s surface into streams and rivers after precipitation.


What is runoff?

400

Wildfires, tailpipes, and industrial smokestacks all emit nitrogen oxides, which—when combined with sunlight—produce this harmful air pollutant that irritates lungs and damages plants.

What is ozone?

400

This common indoor appliance, when malfunctioning, can release dangerous nitrogen dioxide into the home.

What is a furnace?

400

High levels of this nutrient—commonly from detergents and agricultural runoff—can accelerate eutrophication and choke lakes with plant growth.

What is phosphate?

400

This effect occurs when upper air is warmer than the air near the ground, trapping pollutants and worsening air quality.

What is a temperature inversion?

500

This is the name for water stored beneath Earth’s surface in porous rock and sediment layers.


What is groundwater?

500

This type of pollution occurs when chemicals like PCBs or mercury accumulate in aquatic organisms, intensifying at higher levels of the food chain.

What are toxic chemicals?

500

Mining and industrial processes that release heavy metals like lead, cadmium, and arsenic create this type of pollution that can contaminate groundwater for decades.

What is leaching?

500

This measurement, often taken by incubating a water sample for 5 days, determines how much oxygen microbes need to decompose organic matter.

What is B.O.D.?

500

When water contains more organic matter, it will have less of this essential substance.

What is oxygen?

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