Earth's Surface
Covered with Water
Chemical Formula
1 Oxygen + 2 Hydrogen
Conservation
Water is Never Lost!
All 3 States
Solid, Liquid & Gas
Earth's Water Cycle
Water is in constant motion. It never disappears: it evaporates from oceans and soil, condenses into clouds, precipitates as rain or snow, and collects back in bodies of water and underground.
Evaporation
The Sun heats liquid water from oceans, lakes, and soil, changing it into invisible water vapor (gas) that rises into the atmosphere.
Condensation
As warm water vapor rises high, it meets colder air. It cools down and turns back into tiny liquid water droplets that gather together to form clouds.
Precipitation
When cloud droplets become too heavy to float in the air, gravity pulls them down to Earth as rain, or as snow/hail if the air is below 0°C.
Collection
Fallen water runs over the ground into rivers and oceans, or soaks deep underground as groundwater. The cycle has no beginning or end and repeats forever!
States of Water & Phase Changes
Water changes its state whenever thermal energy (heat) is added or removed. Adjust the temperature slider below to see how molecules behave!
Particles slide gently past one another, taking the shape of their container.
Test for Pure Water (Effect of Impurities)
"Pure water boils at exactly 100°C and freezes at 0°C at normal atmospheric pressure. If there are impurities (like dissolved salt), water will boil at a higher temperature and freeze at a lower temperature."
Experiment Bench: Heating Both Beakers
Light the burners to observe which beaker boils first and at what temperature.
Thermometer A Reading
• Contains no dissolved minerals or salts.
• Boiling Point: Exactly 100°C.
Thermometer B Reading
• Impurities disrupt water vapor pressure.
• Boiling Point: Higher than 100°C (~104°C).
Textbook Conclusion (Page 25):
When water starts boiling, you will see that the temperature in Beaker A will read exactly 100°C, whereas in Beaker B it will be higher. Hence, measuring the boiling point is an accurate test for determining if water is pure!
Activity 1: Match the State Change
Click a transition card on the left, then click its correct science term on the right!
Grade 6 Science Quiz
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