Key Idea.
Section 1
The Problem with Wastewater
Water is a limited resource. When humans use water for factories or farming, it often gets dirty with harmful substances. This is called wastewater.
This pollution is an environmental problem. We cannot just throw this water away because Earth's supply of freshwater is small. Instead, we need to find a way to clean it so it can be reused.
Section 2
Conservation of Matter
When we try to clean water, it is important to remember a rule of science: Conservation of Matter.
This rule states that matter is never created or destroyed. Even when we treat pollution, the "stuff" doesn't just vanish. It changes form. If we weigh all the materials before and after a treatment, the total weight remains exactly the same.
Expand to review the lesson summary and core properties.
Section 1
The Problem with Wastewater
Water is a limited resource. When humans use water for factories or farming, it often gets dirty with harmful substances. This is called wastewater.
This pollution is an environmental problem. We cannot just throw this water away because Earth's supply of freshwater is small. Instead, we need to find a way to clean it so it can be reused.
Section 2
Conservation of Matter
When we try to clean water, it is important to remember a rule of science: Conservation of Matter.
This rule states that matter is never created or destroyed. Even when we treat pollution, the "stuff" doesn't just vanish. It changes form. If we weigh all the materials before and after a treatment, the total weight remains exactly the same.