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Lesson 2: Student Activity Sheets
These materials were developed with funding through a grant from the Gordon and Betty
Moore Foundation to Northwestern University and the University of Colorado Boulder.
This work is licensed under a Creative Commons Attribution
4.0 License: http://creativecommons.org/licenses/by/4.0/ 1
Name: Period:
Lesson 2: Do only chemical reactions get colder?
Experiment in groups
Procedure
1. Measure and record the temperature of ~50 ml of room−temperature water below.
2. Measure 3g of salt (potassium chloride, kcl) and record its temperature.
3. Add the salt to the water and stir it in.
4. Record the lowest temperature of the mixture. Graph the temperature change.
Note: You might want to take the lowest temperature multiple times to make sure you actually take
the temperature at its coldest!
Substance Temperature
Potassium chloride alone
Water alone
Mixture at lowest temperature
Q1 Record additional observations below.

Temperature ChangeGroup Number
Q5 What new questions do we have that we need to figure out?
Lesson 2: Student Activity Sheets
These materials were developed with funding through a grant from the Gordon and Betty
Moore Foundation to Northwestern University and the University of Colorado Boulder.
This work is licensed under a Creative Commons Attribution
4.0 License: http://creativecommons.org/licenses/by/4.0/ 2
Class Discussion: Sharing Evidence
Collect all of the class data in this table. What pattern are we noticing?
Q2 What do we think is happening to the salt when it dissolves?
(Singhal et al, 2012)
Q4 How might this be similar to or different from the chemical reactions
we’ve already seen?
Q3 Why would there be a temperature drop in the water when the
salt dissolves?

Lesson 2: Student Activity Sheets
These materials were developed with funding through a grant from the Gordon and Betty
Moore Foundation to Northwestern University and the University of Colorado Boulder.
This work is licensed under a Creative Commons Attribution
4.0 License: http://creativecommons.org/licenses/by/4.0/ 3