The Heat Solution | |||
Author(s): Jim Schwagle, Laurie Aiello |
Instrumentation - Teacher's Guide SED 695B; Fall 2005 | ||
Overview: This device shows how a liquid solution, when activated by the physical bending of a metal disk can induce crystals to form and consequently release a large amount of heat. |
|||
Topics addressed:
StandardsHigh School Physics3a. Students know heat flow and work are two forms of energy transfer between systems.3c. Students know the internal energy of an object includes the energy of random motion of the object’s atoms and molecules, often referred to as thermal energy. The greater the temperature of the object, the greater the energy of motion of the atoms and molecules that make up the object.3d. Students know that most processes tend to decrease the order of a system over time and that energy levels are eventually distributed uniformly.3e. Students know that entropy is a quantity that measures the order or disorder of a system and that this quantity is larger for a more disordered system.3f.* Students know the statement “Entropy tends to increase” is a law of statistical probability that governs all closed systems (second law of thermodynamics).High School Chemistry6a. Students know the definitions of solute and solvent.
|
Experiment
| ||
Demonstration Video: |
As the metal disk is flexed the supersaturated solution of sodium acetate is induced into forming crystals that in turn releases considerable stored energy in the form of heat, with the attending rise in temperature.. | ||
Procedure:
Safety:
|
|||
Questions:
|
|||
|
The same process can be illustrated by pouring the solution onto a "seed" crystal, that starts the crystallization process. Heat is radiated from the solid.
| ||
As the solution crystallizes, energy is released from it as shown by the considerable increase in temperature. |
|||
References & Links:
|