BACKGROUND:

Determining the state of matter is not easy.  Many times a substance acts like a liquid, but then sometimes it acts as a solid.  Cornstarch and water is a classic example of  this.  If you add the appropriate amount of water to cornstarch it will act as a solid, but then if you let the solid rest, it will flow.  

Matter can also change states of matter depending on the temperature.  Water is an excellent example of how easily you can go from one state to another, just by increasing or decreasing the temperature.

Traditionally we have taught students that there are 3 states of matter.  They assume that this is all there is.   Solids, liquids, and gases are states of matter that are familiar to us on the surface of the Earth.  However, deep in the Earth or deep  in space, conditions are different, allowing other states of matter to dominate.  For instance, plasma is the most common state of matter in the Universe.  

It is important early in a child’s education to make students understand, that humans define parameters within our world.  But that does not make it absolutely correct in other worlds.

PROCEDURE:

1. Discuss with students that there are 3 states of matter that water takes, liquid, ice, and steam.  In order to change from one state of matter to another energy, heat in this case,  needs to be used.  The problem that the students will explore is how much heat it will take to convert a solid (ice) to a liquid.
       
2. First discuss with students what takes on the different forms of water in nature.
   

3. Give each student a baggy with one ice cube inside.  Have the students feel the coldness.  Tell them that they can use anything in the classroom, including themselves to find a temperature that will melt the ice cube, but make sure students don't use fire.  You may want to disqualify a heater  because that will take some of the fun away.  The one who melts the ice cube the fastest is the winner.  Students will discover that certain places, like armpits will melt the ice cube quickly.  As students are doing this activity, make sure you go over the change of states of matter (solid to liquid).  
     
4. After the students melt the ice cube you may want to put the water into a dish and put it near a window, and have the students look at what happens to the liquid.  This can help emphasize that water goes through another state of matter to form gas (steam).

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