Primary 5 Cycles: Water
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Transcript of Primary 5 Cycles: Water
Water Water
Our Blue PlanetOur Blue Planet
Introduction Introduction
• Covers three-quarters of the earth surface
• All living things need water to survive.
• Water exists in three different states:- Solid- Liquid- Gaseous
Water in Solid State Water in Solid State
ice snow hail
Water in the Liquid StateWater in the Liquid State
• Most of the Earth’s water is sea water.
raindrops
dew clouds
Water in Gaseous StateWater in Gaseous State
Water vapour Steam
Similarities:
•Both are colourless
•Both are water in gaseous state
Differences
At any temperature
1000C
Changing States of Water: Changing States of Water: Heat GainedHeat Gained
• Solid to liquid: Melting (00C)• Liquid to Gaseous : Evaporation
: Boiling (1000C)
Changing States of Water: Changing States of Water: Heat LossHeat Loss
• Liquid to Solid: Freezing (00C)• Gaseous to Liquid : Condensation
Changing States of Water: Changing States of Water: Heat LossHeat Loss
• Liquid to Solid: Freezing (00C)• Liquid to Gaseous : Condensation
MeltingMelting• From solid to liquid• Gains heat• Happens at 00C • Ice to water• Temperature stays the same• Heat gained to change state of water
from solid to liquid• State of water during melting: solid and
liquid
Freezing Freezing
• From liquid to solid• Heat loss from water to the surrounding• Happens at 00C • Water to Ice• Temperature stays the same
Boiling Boiling • From liquid to gaseous• Gains Heat• Happens at 1000C • Water to Steam• Temperature stays the same• Heat gained to change state of water
from liquid to gaseous• State of water: liquid and gaseous
Evaporation Evaporation
• From liquid to gaseous• Gains heat• Evaporation happens all the time and at any
temperature. • Water to Water Vapour
Condensation Condensation
• From gaseous to liquid• Loses heat• Condensation happens due to temperature
difference• Water Vapour to Water • Steam to Water
Condensation Condensation
(1000C)
(100C)
(1000C)
(700C)
Faster Slower
More water droplets
Less water droplets
Evaporation Evaporation
• The rate of evaporation depends on a few factors:- Presence of wind- Humidity - Temperature- Area of exposed surface
Presence of Wind Presence of Wind
• Water evaporates faster in the presence of wind.
• When water evaporates, water vapour gathers above the surface of the water.
• Wind will carry the water vapour away, making space for more water to rise.
Humidity Humidity (Amount of water vapour in the (Amount of water vapour in the
air)air)• High humidity: Large amount of water
vapour in the air
• Higher humidity Slower rate of evaporation
• There is little or no space in the air for any more water vapour when humidity is high.
Temperature Temperature
• Higher temperature Faster rate of evaporation
Area of Exposed SurfaceArea of Exposed Surface
• The larger the area of the exposed surface, the greater the amount of evaporation.
Larger exposed surface area
Smaller exposed surface area
Area of Exposed SurfaceArea of Exposed Surface
0 fold 1fold 2 folds
Increase rate of evaporation
Video on processes of water
Water Cycle Video 1
Water CycleWater Cycle
• Respiration– Animals give out water vapour
Stage 1:• Evaporation
– Heat from sun evaporate water from rivers, lakes and sea
• Transpiration– Plants give out water vapour through
stomata of leaves
Water CycleWater CycleStage 2:• Condensation
– Water vapour rises into the air and condenses into water droplets
Water CycleWater CycleStage 3:• Precipitation
– Clouds become to heavy and fall as rain to the ground
Water CycleWater Cycle
Main source of energy for water cycle
Water Cycle Song: Processes
Water Cycle Song