Water Changes: States of Water

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Water Changes States of Water
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Essential QuestionsWhat are the three states of
water?What is the boiling point of water?What
is the freezing point of water?How does water
change from a solid to liquid to gas?How does
heat or cooling effect how water changes?
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Did you know?

• There is more water on earth than any other
  substance.
• That water covers more than 70 of the Earths
  surface.
• That you are made of more than 50 water.
• Every living thing needs water to live.

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What exactly is water?

• Its a compound composed of two atoms of hydrogen
  and one atom of oxygen. Also known as H2O

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What are the three states of H2O?

• Solid- ice
• Liquid- oceans, rivers,
• lakes
• Gas- water vapor

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What occurs when you heat water?

• One way to change water is to heat it. If you
  take water in its solid state, ______. If you
  heat _______ it does what? ______
• It turns from a solid to a ________.
• This occurs when its temperature rises above 0
  degrees Celsius or 32 degrees Fahrenheit.

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Add more heat to liquid

• And evaporation speeds up.
• What is evaporation you ask?
• It is the change of a substance from the liquid
  to gas state. This occurs more quickly at higher
  temperatures.

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What is the Boiling Point of H2O?

• The temperature that makes water boil is 100
  degrees Celsius or 212 degrees Fahrenheit.
• Have you ever left an uncovered pot of boiling
  water on a stove? What will happen in a short
  time? It will all ____________.
• Therefore you have just turned a liquid into a
  gas by adding ________ which in turn caused
  ___________.

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What happens when you cool H2O?

• Now that you know what happens when you heat
  water does anyone know what happens when you cool
  water?
• When you cool water vapor enough, it undergoes
  __________. Which is the change of a substance
  from the gas to liquid state.
• What occurs when you cool liquid even more? It
  turns to the ________state.

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What makes H2O turn back into a solid state?

• If cooled to 0 degrees Celsius or 32 degrees
  Fahrenheit it will freeze (turn back into a
  solid).

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Can we just skip the Liquid State?

• Yes, this is called sublimation. This is where a
  substance changes directly from a solid to a gas.
  It skips the liquid state in between.
• Just remember that with each change of state that
  there is a gain or loss of heat energy.

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Now lets see what you learned..

• What two elements make up a molecule of water?
• What is water in the gaseous state called?
• What happens when sublimation occurs?
• What happens to water during the evaporation?
• What must happen before water can change from one
  state to another?

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What two elements make up a molecule of water?

• Two parts Hydrogen and one part Oxygen

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What is water in the gaseous state called?

• Water vapor

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What happens when sublimation occurs?

• Water changes directly from ice to water vapor.

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What happens to water during the evaporation?

• It changes from a liquid to a gas state.

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What must happen before water can change from one
state to another?

• It must gain or loose heat.