1. Water Changes: States of Water Created by: Stacey Osborne

2. Essential Questions: What 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?

3. Did you know? There is more water on earth than any other substance. That water covers more than 70% of the Earth’s surface. That you are made of more than 50% water. Every living thing needs water to live.

4. What exactly is water? It’s a compound composed of two atoms of hydrogen and one atom of oxygen. Also known as H2O

5. What are the three states of H2O? Solid- ice Liquid- oceans, rivers, lakes… Gas- water vapor

6. 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.

7. 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.

8. 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 ___________.

9. 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.

11. 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).

12. 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.

13. Now let’s 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?

14. What two elements make up a molecule of water? Two parts Hydrogen and one part Oxygen

15. What is water in the gaseous state called? Water vapor

16. What happens when sublimation occurs? Water changes directly from ice to water vapor.

17. What happens to water during the evaporation? It changes from a liquid to a gas state.changes

18. What must happen before water can change from one state to another? It must gain or loose heat.