1. Physical Properties of Water Boiling Point, Melting Point and Freezing Point

2. Boiling point is the temperature at which something becomes a gas. Water has a boiling point of 100° C. This means that at 100° C, water changes from a liquid to a gas.

3. Melting point is the temperature at which something becomes a liquid. Water has a melting point of 0° C. This means that at 0° C, water changes from a solid to a liquid.

4. Melting Point or Freezing Point? The melting point of ice and the freezing point of water are at exactly the same temperature. The melting point is when solid is changing to liquid. (ice to water) The freezing point is when liquid is changing to solid. (water to ice)

5. Which of the following is the temperature at which ice melts? A. 0 o Kelvin B. 0 o Fahrenheit C. 0 o Celsius D. 0 o Gram

6. Which of the following is the temperature at which ice melts? C.0 o Celsius Correct - The Celsius scale uses 0 o as the melting point. D.0 Gram Incorrect Gram (g) is the measurement unit used to represent mass – not temperature. B.0 o Fahrenheit Incorrect Fahrenheit is the measurement unit that is traditional in the U. S. The temperature would have to be 32 o F for ice to melt. A.0 Kelvin Incorrect Kelvin is the measurement unit that includes absolute zero. The temperature would have to be 274 K for ice to melt.

7. If you are camping at sea level and want to boil water so it will be safe to drink, what temperature will it need to reach? A. 15 K B. 100 o C C. 100 o F D. 150 g

8. If you are camping at sea level and want to boil water so it will be safe to drink, what temperature will it need to reach? A.15 K Incorrect Kelvin is the measurement unit that includes absolute zero. The temperature would have to be 373 o K for water to boil. C. 100 o F Incorrect Fahrenheit is the measurement unit that is traditional in the U. S. The temperature would have to be 212 o F for water to boil. D.150 g Incorrect A gram is the measurement unit for mass – not temperature. B.100 o C Correct The Celsius scale uses 100 o as the boiling point for water.

9. Four students were working together in a lab group. They had to predict the temperature at which water would boil. They recorded their predictions in the table below. StudentPrediction o C 175 290 3100 4125

10. Which student’s prediction was the closest to the boiling point of water? A. Student 1 B. Student 2 C. Student 3 D. Student 4 StudentPrediction o C 175 290 3100 4125

11. Which student’s prediction was the closest to the boiling point of water? C.Student 3 Correct 100 o C is the boiling point of water. StudentPrediction o C 175 290 3100 4125 A.Student 1 Incorrect B.Student 2 Incorrect D.Student 4 Incorrect None of these are the boiling point of water on the Celsius scale.

12. Students were doing a lab to find the melting point of ice. Which thermometer would show the temperature in o Celsius at which ice would begin to melt? A. Thermometer 1 C. Thermometer 3 B. Thermometer 2 D. Thermometer 4 1234

13. Students were doing a lab to find the melting point of ice. Which thermometer would show the temperature in o Celsius at which ice would begin to melt? C correct - because ice melts above 0 o C and the question asks at what temperature ice would begin to melt. 1234 100° 50 ° 0 ° -5 °

14. Three students were discussing what they understood about boiling, freezing and melting point of water. - Sarah thought that the boiling, freezing, and melting point depended on how much water was in the container. - Bill thought that the boiling, freezing, and melting point of water were all the same - 100°C. - Carol thought that the freezing and melting point of water were both the same but the boiling point of water was 100°C. Who do you agree with and why?

15. Three students were discussing what they understood about boiling, freezing and melting point of water. Carol is correct. The freezing and melting point of water are both the same and 0°, but the boiling point of water was 100°C. Sarah and Bill are incorrect. Sarah - Because boiling, freezing, and melting points are physical properties, they do not change just because there is more or less water. Bill - the boiling point is 100°C, but freezing and melting are much lower at 0°.

16. A student drew this illustration in their journal. Discuss all of the information about the boiling point, freezing and melting point of water that is shown in this drawing.

17. Boiling point is 100° Freezing and melting point is 0° Freezing and melting point is the same. Water goes from melting/freezing to liquid and then solid when heat is added. Water goes from gas to liquid and then solid when heat is removed (cooling happens) Boiling point changes liquid water to a gas Melting point changes solid water to a liquid Freezing point changes liquid water to a solid