Water on Earth

The “Blue Planet”

Key Concepts:

1. How do people and other living things use water?

2. How is Earth’s water distributed?

3. How does Earth’s water move through the water cycle?

• Key Terms:

Photosynthesis – is the process by which plants use water, along with carbon dioxide and energy from the sun, to make their own food.

Habitat – the place where it lives and obtains all the things it needs to survive.

Groundwater – water that fills the cracks and spaces in underground soil and rock layers

Water cycle – water moving from bodies of water, land, and living things on Earth’s surface to the atmosphere and back to the Earth’s surface.

Transpiration – water given off through the leaves as water vapor

Precipitation – Water that falls to the Earth as rain, snow, or sleet.

All living things need water.

All Living Things Need Water

What do these things have in common?

They are all made mostly of WATERWater makes up nearly two thirds of your body’s

mass.

As part of their daily routine, these women in Pakistan must walk to a well to get their water. What can you infer about the availability of fresh water in the region where they live.

Body Processes

All living things need water in order to carry out their body processes. In addition, many living things use water for shelter. They find water to survive where it lives, their “habitat”, the place that provides all the things it needs to survive.

How do organisms use water?

Obtain chemicals from their surroundingsBreak down foodGrowReproduceMove food through their body

How do humans and other animals get their water?

Drink it

Eat other foods

Eat other animals

Animals can live weeks without food, but only a few days without water.

Plants and other organisms that make their own food also need water. This process is called “photosynthesis”

6H2O + 6CO2 yields C6H12O6 (sugar) + 6O2

+energy

Photosynthesis is the process by which plants use water, along with carbon dioxide and energy from the sun, to make their own food.

Animals and other organisms depend on the food made by plants during photosynthesis. Animals either eat the plants, or eat the animals that eat the plants.

This occurs in both saltwater and freshwater.

Water also provides some animals a place to live……….it’s “habitat”.

• What is a habitat?

A. a well that contains water

B. the process by which plants make their own food

C. a body process that requires water

D. the place where an organism lives

Distribution of Earth’s Water

97% of Earth’s water----is salt water found in the oceans

Only 3% is fresh water

Of the 3%....75% is frozen and unusable 24.9% is underground a tiny fraction is in rivers and lakes an even smaller fraction is water vapor

OceansThe ocean is really one BIG ocean….all of

the oceans are connected!

The 3% left is located mostly at the North and South Poles.

Unusable

True or False: Icebergs are formed from frozen salt water.

False.

Ice made from saltwater is actually a form of “desalination.” This is the separation of salt from water. Where else is desalination used?

• Groundwater – spread out and hard to get to. Groundwater is water that fills the cracks and spaces in underground soil and rock layers.

Rivers and Lakes – 20% of all the freshwater in lakes are

located in the Great

Lakes

Parts of the Water Cycle

The water cycle naturally recycles water. It is powered by the energy from the sun and is an ongoing process.

The water cycle involves all living things, as living things breath out water, and humans use water in all parts of their life.

Remember from Section 1 that water evaporates from the surface of the water.

For millions of years, the total amount of water on Earth has remained fairly constant----rates of evaporation and precipitation are balanced.

Active Art self quiz

phschool.com

Cfp-4024

Transpiration – water loses water through the leaves as water vapor…..yes, you could do this.

Review

How do people and other living things use water?

Body processesShelterBreak down foodGrowReproduceMove substances within their body

How is Earth’s water distributed?

Oceans

Lakes and Rivers

Ice

Groundwater

How does water move through the water cycle?

Evaporation from oceans, lakes, plants

Condensation

Precipitation

Surface runoff from groundwater/rivers