Change Of State

Bernard Hudson Morton Career Academy
431 N. Troy Street
Chicago, Il. 60612
(312) 534-6791


The students will
1. Note the change of state of Butyl Stearate (BS).
2. List the characteristics of BS in solid and in liquid forms.
3. Note the temperature at which liquid goes to solid.
4. Note the temperature at which solid goes to liquid.
5. Chart the temperature vs. time change solid to liquid.
6. Chart the temperature vs. time change liquid to solid.

Materials needed:

For a class of 15:
1. 15 Test Tubes
2. 30 Beakers
3. 15 Thermometers
4. 15 Hot Plates
5. 500 mL Butyl Sterate
6. Ice/Water
7. 15 pr. Goggles
8. 15 Aprons
9. Paper Towels
10. Clock/Watch
11. 1 each, package gelatin ('Jello' brand or equivallent) & 1 prepared
12. 1 each, package 'Kool-Aid' brand drink mix & 1 popsicle
13. 1 each, pitcher, mixing bowl, spoon


1. Discuss how mother makes 'Jello'.
2. Ask students to help make 'Jello'.
3. Display solidified 'Jello', note if it is wet or dry.
4. Introduce the terms solid and liquid.
5. Discuss how 'Jello' changes from liquid to solid.
6. Ask students to predict what may happen if we heated solid 'Jello'.
7. Demonstrate how solid 'Jello' returns to liquid with heat.
8. Do the same procedure with 'Kool-Aid' and a popsicle.
9. Have children list physical properties of both substances and note
on their worksheets which properties change with the changing
states and which properties remain the same.
10. Have students read aloud laboratory directions and tell what they
are to do when they move to the laboratory.
11. Have students describe butyl stearate as a liquid and experiment
with placing a test tube of this liquid in boiling water and in ice
12. Have students repeat changing states several times.
13. Ask what is required to change the state. (Heat must be added or
14. After students have made the connection between temperature and
state, ask them if they think they could find the temperature at
which a change of state takes place.
15. Supply a thermometer and let students find the temperature of the
two water baths.
16. Ask students to place their thermometer in liquid Butyl Stearate
and place the test tube in the ice water bath. They must chart the
temperature drop until all the liquid solidifies.
17. Repeat going from solid back to liquid.
18. Teacher will graph one or more of these charts on the front board
and discuss the meaning of the results.
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