Water Phase Change Lab

Transcription

1 Water Phase Change Lab by Skipper Coates Time Needed: About 40 minutes Background Knowledge Required: Students should know that the addition of heat speeds up molecules, resulting in phase changes. Materials Needed: Student lab sheet 1 per student 500 ml beakers 1 per student group Bunsen burner or hot plate 1 per student group o If using a Bunsen burner you will also need: o Ring stand, ring, and gauze o Lighter Thermometer 1 per student group Thermometer clap (optional, but recommended) 1 per student group Tongs 1 per student group 300 ml water Teacher Prep Time: About 8 minutes Teacher to do List: Print and copy the Water Phase Change Lab sheet 1 per student Organize lab supplies. Remember, each group will need: o A 500 ml beaker, Bunsen burner or hot plate, thermometer (with clamp if possible), tongs, and water Print and place the lab station numbers (optional) Font Used in this product: Pea Katrina, by Kevin and Amanda

2 Good Luck! And happy teaching! Skipper Coates Don t forget to rate this product, and thank you again! If you enjoyed this product, you may enjoy these other products in my TpT store:

3 Name Date Class Water Phase Change Lab Water can be found on the Earth in three phases: solid, liquid, and gas. Water will change phases when energy is added or taken away from the individual water molecules. During these changes the water molecules change their appearance, which means that phase changes are PHYSICAL changes. Your goal is to record and graph data as water is changed from a liquid into a gas. Materials needed for each group: 500 ml Beaker Bunsen burner or hot plate o Lighter, ring stand, ring, and gauze, if using a Bunsen burner Thermometer o Thermometer clamp Tongs Water Prediction: At what temperature do you think the water will boil (change from a liquid to a gas)? Procedure: 1. Fill beaker with 300 ml of room temperature water 2. Insert thermometer into the water. Be sure to use a thermometer clamp or to hold the thermometer so that it is not resting against the glass. 3. Record the temperature of the water after 90 seconds (at time 0) 4. Light the Bunsen burner, or turn the hot plate onto HIGH 5. Record the temperature every 30 seconds for the next 12 minutes. Data Table: Time Temperature Time Temperature Time Temperature 0 4:30 9:00 0:30 5:00 9:30 1:00 5:30 10:00 1:30 6:00 10:30 2:00 6:30 11:00 2:30 7:00 11:30 3:00 7:30 12:00 3:30 8:00 4:00 8:30 Make a line graph of your data:

4 Time (minutes) Interpreting Data: 1. How long did it take your water to boil? 2. What was your maximum temperature? 3. Why didn t your water go any higher than the maximum temperature? 4. Use three sentences to explain what was happening to the water molecules during this lab:

5 5. Draw a picture of what the water molecules looked like before the experiment AND at the end of the experiment: Water Molecules BEFORE Water Molecules AFTER 6. Draw a graph that would illustrate liquid water being turned into solid water: Temperature C Time

6 Conclusion: 7. Water boils at 100 C in Florida and at about 94 C in Utah. Propose an explanation for this difference in boiling point : 8. A friend of yours does not believe that boiling water is a physical change. Write a three sentence conclusion to this lab that explains why water phase changes (like boiling, melting, and freezing) are physical changes:

7 Name STUDENT ANSWER SHEET Date Class Water Phase Change Lab Water can be found on the Earth in three phases: solid, liquid, and gas. Water will change phases when energy is added or taken away from the individual water molecules. During these changes the water molecules change their appearance, which means that phase changes are PHYSICAL changes. Your goal is to record and graph data as water is changed from a liquid into a gas. Materials needed for each group: 500 ml Beaker Bunsen burner or hot plate o Lighter, ring stand, ring, and gauze, if using a Bunsen burner Thermometer o Thermometer clamp Tongs Water Prediction: At what temperature do you think the water will boil (change from a liquid to a gas)? Procedure: 6. Fill beaker with 300 ml of room temperature water 7. Insert thermometer into the water. Be sure to use a thermometer clamp or to hold the thermometer so that it is not resting against the glass. 8. Record the temperature of the water after 90 seconds (at time 0) 9. Light the Bunsen burner, or turn the hot plate onto HIGH 10. Record the temperature every 30 seconds for the next 12 minutes. Data Table: Answers vary depending on altitude Time Temperature Time Temperature Time Temperature 0 4:30 9:00 0:30 5:00 9:30 1:00 5:30 10:00 1:30 6:00 10:30 2:00 6:30 11:00 2:30 7:00 11:30 3:00 7:30 12:00 3:30 8:00 4:00 8:30

8 Make a line graph of your data: Temperature ( C) Time (minutes) Interpreting Data: 9. How long did it take your water to boil? Answers will vary depending on altitude. 10. What was your maximum temperature? Will be between C 11. Why didn t your water go any higher than the maximum temperature? Once water reaches its boiling point the molecules escape as a gas and are no longer liquid 12. Use three sentences to explain what was happening to the water molecules during this lab: Answers will vary, but students should mention that increasing temperature will cause the water molecules to move faster until they change phases

9 13. Draw a picture of what the water molecules looked like before the experiment AND at the end of the experiment: Water Molecules BEFORE Water Molecules AFTER 14. Draw a graph that would illustrate liquid water being turned into solid water: Temperature C Time

10 Conclusion: 15. Water boils at 100 C in Florida and at about 94 C in Utah. Propose an explanation for this difference in boiling point : The correct answer is that air pressure is greater at sea level (Florida). As altitude increases the air pressure decreases, making water molecules escape and become gases more easily. 16. A friend of yours does not believe that boiling water is a physical change. Write a three sentence conclusion to this lab that explains why water phase changes (like boiling, melting, and freezing) are physical changes: Physical changes cause changes to the appearance of a substance. A phase change, like boiling water, also causes a change to the appearance of a substance. Liquid water molecules and gas water molecules both have the same chemical structure (H 2 O) even though they look different.