Earth’s Water Distribution
About what percentage of Earth’s surface is covered by oceans?
About 70%
What are the three states of water found on Earth?
Solid, liquid, and gas
What gas form of water is found in the atmosphere?
Water Vapor
What does polarity mean in a water molecule?
Water has uneven charges, with a slightly positive side and a slightly negative side.
What does the pH scale measure?
How acidic or basic a substance is
What type of water makes up about 97% of Earth’s total water?
Salt water
What is the chemical formula for water in all its states?
H₂O
What process forms clouds when water vapor cools and turns into liquid droplets?
Condensation
What is cohesion
the attraction between water molecules, causing them to stick together
What is the pH of pure water?
7 (neutral)
What percentage of Earth’s water is fresh water?
About 2.5%
What happens to water molecules when water gains energy?
They move faster and may change to a less dense state
What are three common types of precipitation?
Rain, snow, and hail
What is adhesion?
The attraction between water and other substances
What does turbidity describe?
How cloudy or clear water is
Why is most of Earth’s fresh water not easily available for humans to use?
Because nearly 70% of it is frozen in ice
What process changes liquid water into water vapor?
Evaporation
What percentage of atmospheric water comes from evaporation?
About 90%
Why does ice float on liquid water?
Ice is less dense than liquid water.
What is dissolved oxygen (DO)?
Oxygen mixed into water that aquatic organisms need to breathe
Explain the most important reason why protecting Earth’s water resources is important.
Only a small amount of fresh water is available for drinking, farming, and life, so it must be protected from pollution and waste.
When water vapor changes directly into ice without becoming liquid, what is this process called?
Deposition
How do hailstones grow larger inside clouds before falling to Earth?
Strong winds carry them up, and more water freezes onto them each time they fall and rise again.
Why is ice floating important for aquatic life?
It insulates the water below, allowing organisms to survive in cold temperatures.
Why is dissolved oxygen important for aquatic ecosystems?
it is the primary source of respiration for fish, invertebrates, bacteria, and plants. With out them they can't survive