Name: ______CP: ____ Date: ______

From Ice to Steam Progressive Activity

Part 1.

Suppose you do the following two steps:

Step A: First you fill a pot halfway with water and cover it with a glass lid.

The lid has a hole big enough for a thermometer to fit through. The

thermometer reads +20C (+68F), ordinary room temperature. You let

the water sit like this for 10 minutes.

Step B: Next, you set the pot on a stove, and you turn on the stove to medium.

You let the pot heat up for 10 minutes, and at the end of this time the water is

barely ready to start boiling. (Water starts boiling at 100C.)

Assume no heat or water leaks away from the pot.

Questions:

1. a) How much was the starting temperature of the water (at the beginning of Step A)? ______

b) How much was the final temperature of the water (at the end of Step B)? ______

2. At what moment did the water temperature start to

increase? Why?

3. On the diagram at the right, draw a graph that shows

the temperature of the water for the entire 20 minutes:

10 minutes with the stove OFF and then

10 minutes with the stove ON.

4. In the example above, you turned the stove on

to MEDIUM heat. How would the graph look if

you had turned the stove on to HIGH heat instead?

Show how the graph would look bydrawing a new

line on the same diagram at theright. Make it a dotted

line instead of a solid line. 0 First, let the pot sit for 10

minutes (stove OFF),and then turn the stove on

HIGH. Stop drawingwhen the water is barely ready to

start boiling.

Now suppose you try these steps

Part 2.

Step A: You put some water into the pot, cover it with the lid, and insert the thermometer.

Step B: You set the pot in the freezer and leave it there for a couple of days.

Step C: After a couple of days, you take the pot out of the freezer. You notice that the water has frozen solid,

and the end of the thermometer is stuck in the ice. You check the thermometer and write downthe

initial temperature “Tinitial” of the ice.

Step D: Right after taking it out of the freezer, you put the pot on the stove over a gentle flame. The flame adds

heat at a steady rate. As the flame continues to add heat to the pot,you check the pot every once in a

while and write down the temperature.

Step E: The ice does NOT begin to melt until it has been on the stove for 15 minutes.

Step F: Eventually all the ice melts. You continue to check the temperature every once in a while.

Step G: After a while, you notice that the water is starting to boil.

Questions:

4. What do you think was the initial temperature Tinitial of the iceat the moment you took it out of the freezer?

(If you are not sure, just give your best guess.) ______C

5. Suppose that you wanted to make a graph showing how temperature changes over time. What do you think

the graph would look like? Make a guess by drawing the graph below. Think about the numbers on the graph

as you draw. The graph does not have labels for the hours or minutes, so it is OK to simply guess the times. If

you are not sure what to do about the numbers, at least try to guess the shape of the graph. Is the graph made

up of sloping lines? flat lines? curves?

6. At the very beginning of your graph, all of the water is SOLID ice.

a) At what point on your graph does the ice begin to melt and some LIQUID water start to form? Label this

pointon your graph.

b) At what point on your graph does the ice finish melting? Label this point on your graph.

c) At what point on your graph does the liquid water begin to boil and some GAS water start to form? Label

this point on your graph.

Part 3.

In part 2, you took a pot of ice out of the freezer, put it on a stove, and turned on the heat. Gradually the ice melted into liquid water, and then the water slowly got hot. If you kept the stove on, the water would soon get to boiling, and it would boil away into steam. Throughout this entire process, imagine that you watched the temperature and wrote it down every few minutes.

The table below shows the information you might get for turning ice into water and then into steam.

Plot this data on the graph below.

Questions:

Refer to the graph you created above as you answer the following.

7. What was the initial temperature of the ice at the moment you took it out of the freezer? ______C

Is this a typical kitchen freezer like you have at home? Explain.

8. For what parts of your graph is a phase change taking place?

At what temperature is there a mix of SOLID and LIQUID?

At what temperature is there a mix of LIQUID and GAS?

Label these parts of your graph MELTING POINT/FREEZING POINT and BOILING

POINT/CONDENSATION

9. The graph has different sections.

There are three sections of the graph

where the temperature is increasing.

List these 3 sections here:

section

A from __12:00__ to __12:15____

C from ______to ______

E from ______to ______

There are two sections of the graph

where the temperature is NOT increasing, but heat is still being added.

List these 2 sections here:

section

B from ___12:15__to ______

D from ______to ______

10. Zack says, “During sections A, C, and E, the stove is adding heat to the pot.” Do you agree or disagree?

Why?

11. Annie says, “During sections A, C, and E, the molecules of water were gaining speed.” Do you agree or

disagree? Why?

12. Mick says, “During sections B and D, the stove was not adding heat to the pot.” Do you agree or disagree?

Why?

13. Bonnie says, “During sections B and D, the molecules of water were gaining energy.” Do you agree or

disagree? Why?

14. Sometimes you can put in heat but NOT increase speed of the particles. Where does the heat energy go?

15. Do think phase change is a physical change or a chemical change? Explain your reasoning.

16. Do you think the temperature at which a substance undergoes a phase change is a physical or a

chemical property? Explain your reasoning.