Part 1: The Water Cycle
Water Cycle
 Water is always on the move.
Rain falling where you live may
have been water in the ocean
just days before. And the water
you see in a river or stream
may have been snow on a high
mountaintop.
 The water cycle is also known
as the hydrologic cycle.
 Fun Fact:

Hydro is Latin for water
Where is water?
 Water can be in the
atmosphere, on the land, in
the ocean, and even
underground. It is recycled
over and over through the
water cycle.
 In the cycle, water changes
state between liquid, solid
(ice), and gas (water vapor).
Stage 1 : Evaporation
 Evaporation means to
turn water from a liquid
into a gas, or “vapor.”
 Evaporation turns the
water that is on the
surface of oceans, rivers,
& lakes into water vapor
using energy from the
sun.
Stage 2 : Transpiration
 When water evaporates
from plants it is a process
called transpiration.
 Plants lose water through
their stems, leaves, and
roots.
 A fully grown tree may lose
several hundred gallons of
water through its leaves on a
hot, dry day.
Stage 2: Condensation
 Condensation is the process
by which water vapor in the air
is changed into liquid water.
 How does this happen???
The water vapor rises in the
atmosphere and cools, forming
tiny water droplets.
 Those water droplets make up
clouds.
Stage 3: Precipitation
 Those water droplets that CONDENSE make up
clouds. If those tiny water droplets combine with
each other they grow larger and eventually
become too heavy to stay in the air. Then they fall
to the ground as rain, snow, and other types of
precipitation.
Stage 3: Precipitation
 Precipitation is water
released from clouds
in the form of rain,
freezing rain, sleet,
snow, or hail. It is the
primary way water is
delivered from the
atmosphere to the
Earth.
Did you know…
 How many gallons of water fall when 1 inch (2.5 cm) of
rain falls on 1 acre of land?
 27,154 gallons of water!
 Rain drops are not tear shaped.
 They start out in a ball shape, but as they fall they meet with air
resistance, which starts to flatten out the drop until at about 2-3
mm in diameter the bottom is quite flat with an indention in the
middle - much like a hamburger bun. When raindrops reach about
4-5 mm, things really fall apart. At this size, the indentation in the
bottom greatly expands forming something like a parachute with
two smaller droplets at the bottoms. The parachute doesn't last
long, though, and the large drop breaks up into smaller drops.
Wow! That is amazing!
 The world's record for average-annual rainfall belongs
to Mt. Waialeale, Hawaii, where it averages about 450
inches (38 ft) per year.
 The world’s recorded for least amount of rain goes to
Antofagasta Region, Atacama Desert, Chile at zero in
one year!
 It takes 6 gallons of water to grow the potatoes for your
order of fries!
 For your hamburger it takes 1300 gallons of water to
produce everything needed!
Stage 4A: Runoff
 Runoff is the ways in
which water moves
across the land.
 As it flows, the water
may seep into the
ground, evaporate into
the air, become stored in
lakes or reservoirs, or be
extracted for agricultural
or other human uses.
Stage 4B: Infiltration
 Infiltration. is the
precipitation that soaks
into the ground and
becomes a part of the
groundwater.
Where Does Water Go When it
Rains? (Video)
 https://www.youtube.com/watch?v=7zjPqA2FIns
Stage 5: Accumulation
 Accumulation is the process in
which water pools in large bodies
(like oceans, seas and lakes)
Most of the water on Earth is in
the Ocean.
 Did you know?
 Water stays in certain places longer
than others. A drop of water may
spend over 3,000 years in the ocean
before moving on to another part of
the water cycle while a drop of water
spends an average of just eight days
in the atmosphere before falling
back to Earth.
Water Cycle Video and Rap!
 https://www.youtube.com/watch?v=ZzY5-NZSzVw
 https://www.youtube.com/watch?v=i3NeMVBcXXU
Pt. 2: What is pH?
 What is pH?
 pH is a measure of how acidic or
basic a solution is.
• The pH scale ranges from 0 to 14.
 Acidic solutions have pH values
below 7
 A solution with a pH of 0 is very
acidic.
 A solution with a pH of 7 is neutral.
• Pure water has a pH of 7.
• Basic solutions have pH values above
7.
Properties of an Acid
 Tastes Sour
 Conduct Electricity
 Corrosive, which means
Picture from BBC Revision Bites
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b
ases_1.shtml
they break down certain
substances. Many acids
can corrode fabric, skin,
and paper
 Some acids react strongly
with metals
 Turns blue litmus paper
red
Pt. 3: Acid Rain
Definition of Acid Rain
 Acid Rain is precipitation that has a higher than
normal acid level
 It is formed when sulphur dioxides and nitrogen
oxides combine with water vapor and fall to the
Earth as acids in rain, snow, or fog.
Causes of Acid Rain
 The main cause of acid rain is from human sources
 Sulphur dioxide and nitrogens are released when fuel is
burned
Examples:
 Industrial factories
 power-generating plants
 vehicles
MSN Encarta
Effects of Acid Rain
 Harmful to plants
 Speeds up the process of weathering in metal and
stone structures
 Eg. Parthenon in Athens, Greece; Taj Mahal in Agra,
India
 Affects human health
Preventive Measures
 Use cleaner fuels
 Examples:
 Coal that contains less sulphur
 Natural Gas
 hydro-electricity
 wind energy
 geothermal energy
 solar energy