The Science behind

Science in a Snap!

The Molecule Masher is a supersaturated solution of sodium acetate.  It is a type of salt mixed in water and because it is supersaturated sodium acetate it is a very salty solution.  This solution is happy to remain in its liquid state, but each molecule holds a small bit of stored energy called potential energy.  By flexing the disc inside, the Molecule Masher you break the molecular chain in a single molecule.  This releases the stored potential heat energy in that molecule.  Once one molecule “flips” and releases its stored energy it starts a chain reaction that will cause all the other molecules to flip and release their stored heat energy.   The location where the reaction begins is called the nucleation point.  In this reaction there is also a change in physical state of matter.  The solution crystallizes or changes from a liquid to a solid in the same way water changes to ice when enough cold energy is applied.  The Molecule Masher will remain warm for 20+ minutes, but to repeat the experiment again, the stored potential energy needs to be restored.  The easiest way to do this is (with adult supervision) place the Molecule Masher in a pot of gently boiling water until all the crystals dissolve (about 8-10).  Once the Molecule Masher cools to room temperature it is ready to be used again.

 

Vocabulary Words:

 

Endothermic reaction—a chemical reaction that results in the absorption of heat or the solution getting cooler.

 

Exothermic reaction—a chemical reaction that produces an increase in temperature or gives off heat.

 

Supersaturated—super saturation refers to a solution that contains more of the dissolved material than could be dissolved under normal circumstances, when the Molecule Masher solution is originally boiled, a higher concentration of sodium acetate can be dissolved than by mixing alone.  This super saturation makes the chemical reaction possible.

 

Nucleation Point—the location where a reaction begins.

 

Physical state—the state of matter—solid, liquid or gas.

 

Law of Conservation of Energy—in short states that energy cannot be created or destroyed; it can only be changed from one from to another, such as when electrical energy is changed into heat energy.

 

 

Experiment Demonstration:

 

Show the group the Molecule Masher that contains the supersaturated sodium acetate solution.  Ask if any of them have seen one before.

 

Distribute the Molecule Masher to your audience.

 

One person in each group should pinch and flex/bend the disc floating in the solution.

 

They will see a crystallized solid beginning to form around the disc.  If they don’t, the disc should be flexed one more time.

 

Ask the group to explain what they are seeing and feeling.

 

Explain the reaction.

 

Ask them to explain how the Molecule Masher illustrates the law of conservation of energy.  (Heat energy is released when the disc is flexed, which causes crystallization of solid from the solution.  Heating in boiling water is required to restore the hand warmer to its liquid state, which restores potential heat energy into the system.)

 

Point out that the Molecule Masher can be recharged by placing it in a pan of hot water for several minutes (directions are given on the back of the Molecule Masher) replacing stored potential energy back to the system.

 

 

Additional Experiment:

 

The Molecule Masher will peak at a temperature of about 120 degrees F.  But this can be manipulated as well.  There is a set amount of potential energy stored in each Molecule Masher, as the number of molecules is a constant (it doesn’t change).  This can be demonstrated with three Molecule mashers.  Leave one at room temperature, put one in the freezer and one in the refrigerator for a couple of minutes each.  You want to make sure there is an obvious difference in temperature between the three before starting the experiment.  Then, flex all the discs and observe the differences.

 

You should find that the one from the freezer will not  reach as high of a temperature as the other two.  It will also become a solid more quickly and its heat will not last as long.  The one from the refrigerator will reach the usual temperature range of 120-130 F, but you will see that it will cool more quickly.  (A greater amount of energy is burned to heat the cooled Molecule Masher so it cannot sustain the heat for as long as the one left at room temperature). The one that started at room temperature will perform as usual, heating and staying warm for 20-30 minutes.

 

Try this too!  The easiest, most efficient way to restore the potential energy is by boiling the Molecule Masher in a pot of water, but you can use solar heat to liquefy it as well.  Place it on a car dashboard or a window in direct sunlight on a warm, sunny day and the sun will do the work!

 

 

PLEASE NOTE:  Microwaves will work too, but  DO NOT TRY THIS!  There is a metal disc inside the pouch and the PVC plastic pouch is not microwave safe.  The metal disc will blister the pouch and potentially cause a hole.