Water Cycle

The Water Cycle

What is Water Cycle

The water cycle shows the continuous movement of water within the Earth and atmosphere. It is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.

Why is it Important?

All life is dependent upon water. Water makes up 60 to 70 percent of all living matter and humans cannot live without drinking water for more than a week. The water cycle, or hydrologic cycle, distributes fresh water all over the earth's surface.If water didn’t naturally recycle itself, we would run out of clean water, which is essential to life.

​https://gpm.nasa.gov/education/sites/default/files/videos/GPM%20-%20The%20Freshwater%20Connection.mp4

Let's watch a video

Think-Pair-Share

​“why is it important to learn and understand the water cycle?”

“what are your ideas when you think about the water cycle?”

The most basic step of the water cycle is the change of state of water as a liquid, gas or solid in the atmosphere.

It is made up of processes; transpiration, evaporation, condensation, and precipitation.

The Water Cycle

​ 1. Evaporation

2. Transpiration

3. Condensation

4. Precipitation

Evaporation

the transfer of water from the surface of the Earth to the atmosphere. By evaporation, water in the liquid state is transferred to the gaseous, or vapour, state.

​Transpiration

the evaporation of water through minute pores, or stomata, in the leaves of plants. For practical purposes, transpiration and the evaporation from all water, soils, snow, ice, vegetation, and other surfaces are lumped together and called evapotranspiration, or total evaporation.

Condensation

the transition process from the vapour state to the liquid state. Condensation may take place as soon as the air contains more water vapour than it can receive from a free water surface through evaporation at the prevailing temperature.

Precipitation

distributed in four main ways: some is returned to the atmosphere by evaporation, some may be intercepted by vegetation and then evaporated from the surface of leaves, some percolates into the soil by infiltration, and the remainder flows directly as surface runoff into the sea.

​ 1. Evaporation

2. Transpiration

3. Condensation

4. Precipitation

​(89) Water Cycle | How the Hydrologic Cycle Works - YouTube

Let's watch a video

Quiz 1

Multiple Choice

An ice cube placed in sunlight melts quickly. Which best explains this event?

• The ice cube is solid

• The ice cube is clear

• The sun makes heat

• The sun is too far from the ice cube

Multiple Choice

What is the only thing in nature that can be solid, liquid or gas?

• Hydrogen

• Oxygen

• Nitrogen

• Water

Multiple Choice

What is evaporation?

• Water freezes

• Plants take in water from soil

• Water gets warm and changes from liquid to vapour state

• Water vapor meets cold air and changes back into liquid

Multiple Choice

True or False: Precipitation is part of the water cycle

• True

• False

Multiple Choice

The constant movement of water from Earth's surface to the atmosphere and back to Earth's surface

• Water Vapor

• Water Cycle

• Transpiration

• Precipitation

Multiple Choice

A cold, closed bottle of water is left in the sun. Water forms on the outside of the bottle. This is an example of ______

• Evaporation

• Condensation

• Transpiration

• Rainfall

Multiple Choice

How do clouds form from water vapor?

• precipitation then condensation

• evaporation then precipitation

• evaporation then run off

• condensation then precipitation

Demonstration

Evaporation

Materials:

• Hand Sanitizer

• Stopwatch

• Pen and Paper

Evaporation

(a) Divide the class into pairs and give each pair a small bottle of hand sanitizer and a stopwatch. Make sure the students have their notebooks to record their data.

(b) Have one student start the stopwatch when the other student squeezes a small amount of hand sanitizer onto their hands and rubs them together three times.

(c) The student with the hand sanitizer on their hands should hold their hands still until their hands are dry.

(d) When that occurs, the other student will stop the stopwatch and record the time.

(e) The students will switch roles and repeat the experiment again.

Transpiration

Materials:

• Medium-sized plant (well-watered)

• 2 plastic bags

Transpiration

(a) Take a medium sized well-watered plant.

(b) Cover the plant completely and tie its mouth around the base of stem.

(c) Take a similar empty plastic bag and tie its mouth.

(d) Keep the plant as well as the empty plastic bag in sunlight for 1-2 hours.

Condensation

Materials:

• Jar or beaker (1 per group)

• Ice

• Hotplate

• Plate

Condensation

(a) Begin by heating up some water to boiling and then pour it into the jar, filling the jar about one-third full.

(b) Place the plate over the jar and wait 2 minutes.

(c) Place ice cubes on top of the plate.

(d) Have students observe and make predictions about why it is raining inside the jar.

Activity

The Water Cycle Poster

Make a mini-poster with a diagram of the water cycle.

• Make a diagram with labels of the phases of water cycle and including sun as its heat source.

• Explain the cycle in one paragraph.

-End of Presentation-

Thank You