SOLID TO LIQUID

OBJECT:

To observe the change in temperature, when a solid changes to a liquid.

MATERIALS:

SAFETY GOGGLES, Two large jars ( about 1 Pint ), Water ( about 50 ml or one half full of the spice container National brand ( McC...)), Ice ( two cubes ), Stirring rod ( Make a straw stirring device, like the way you made the Hydrometer or use your Hydrometer ), Centigrade thermometer, and Salt ( about quarter full of the spice container ).

PROCEDURE:

SAFETY FIRST, Be sure to take every possible precaution to prevent INJURY by using SAFETY GOGGLES.

1. Record the room temperature._________°C

2. Fill one jar with 100 ml of water.

3. Record the temperature of the water._________°C

4. Add the water to the second jar that contains the ice cubes.

5. Stir gently, (If no, stirring device, and you are using your Thermometer) until there is no change in the temperature. ( Note: Thermometers are expensive !)

6. Record the lowest temperature obtained. _________°C

7. Do not remove the thermometer out of the jar. Take all readings while the thermometer is in the water.

8. Now, add the salt and continue to stir.

9. Observe the temperature. Is it dropping?

10. Continue to stir until there is no change in the temperature.

11. Record your lowest temperature. _________°C

12. Record the change, that takes place on the outside of the jar.

13. Has any ice formed on the outside of the jar and where?

QUESTIONS:

1. Explain what is the difference between a Fahrenheit temperature scale and a Celsius temperature scale.

2. List three quantitative physical properties of water.

3. List several qualitative physical properties of water.

4. How long will the temperature remain the same, when heating water with ice?

5. Explain, when is it possible to raise the temperature of water above 100°C.

6. Refer to the graph below, for the following questions: The graph represents, heating ice in water, until it reaches the boiling point.

(a) What do the line segment A-B and C-D represent?

(b) When will the line segment A-B change? ( longer - shorter )

(c) When will the slant of line segment B-C change? ( increase or decrease slant ) Explain.

7. At about what temperature would you expect water to boil on a very high mountain? Explain why.

(a) At sea level, at what temperature does water boil on the Celsius temperature scale? ______

(b) At what temperature does water freeze on the Celsius temperature scale? ______

(c) What is the significance of water temperature reaching 4°C ?

8. If there are any impurities in the water, explain how this would effect the boiling and freezing point of the water.

9. If a molecule has a lot of heat, it means that it also has a lot of ____________.

10. To change from a solid to a liquid you need __________.

11. To change a solid salt to a liquid the molecules need ___________.

12. When the ice changed to a liquid, where did it get the energy?

13. Why did the temperature dropped, when the salt dissolved?

14. When the salt changed to a liquid ( dissolved) where did it get the energy?

15. Compare the speed of a molecule in a solid, liquid, and a gas.

16. What happens to the volume of most kinds of matter when (a) it is heated, (b) it is cooled?

17. What happens to the volume of most kinds of matter when it is cooled to the point when it becomes a solid. How is water an exception to this rule?

18. What is the density of Ice?

19. Work the following problems.

(a) 41 °F = _______ °C

(b) 50 °F = _______ °C

(c) 59 °F = ________ °C

(d) 7 °C = ________ °F

(e) 18 °C = ________ °F

(f) 28 °C = ________ °F

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