Kids Chemistry Solutions

In chemistry, a solution is when something (a solute) is so thoroughly dissolved in something else (a solvent) that they become one homogeneous mixture.  In real life, we do this all the time!

First up we sprinkled crystals of Kool-Aid (from the packet, not the sugared variety) into water and watched them dissolve.  You can see the crystals fall through the water trailing streamers of dissolved red.

Then we looked at the effect of heat and stirring on the rate of dissolution (dissolving). 

I set up four jars, two with ice water, and two with boiling water.

Then I dropped a bouillon cube into each jar.  The first jars had hot or cold water; the second set also had one hot, one cold, but we added spoons to stir with.

The hot stirred cube dissolved first, followed by the hot jar with no stirring.  Neither cold jar showed much dissolution.

 Next up we looked at how quickly gummy worm segments dissolved in our mouths.  This was a favorite experiment!

Each kid got three small segments.  For the first, they had to hold it in their mouths without moving it around for one minute.

For the second, they moved it around their mouths for one minute.  For the third, they chewed it for one minute.  Making your solute smaller and moving it around definitely speeds dissolution!

 Next we discussed saturated solutions.  For most solutes and solvents, there comes a point at which no more solute can be absorbed by the solvent.  We did this with sugar and water, adding sugar until no more could be stirred in.

Then we put the pot on the stove and made a super saturated solution.  We got the solvent to hold more solute by adding heat!

Sure enough, the leftover sugar went into solution as soon as the water was hot.  We set it aside to cool and eventually added it to the Kool-Aid solution to make, well, Kool-Aid!

Of course, some solutes will not combine with some solvents.  We call them immiscible, and the obvious example is oil and water.  I had each kid make a bottle with oil and colored water (and glitter, feathers, beads and whatever else looked fun).  

Lastly, when is a solution not a solution?  When it is a suspension or a colloid. 

In a suspension, the solute is not at all absorbed by the solvent, and the particles will eventually settle out. An example of this would be a flour water mixture.

In a colloid, the particles will not settle out, but they remain somewhat distinct from the solvent.  Milk and jello are both colloids. 

You may be wondering in what way the particles in jello and milk are somewhat distinct!  There is a fascinating and easy test known as the Tyndale effect.  Just shine a beam of light through your solution (probably in a dark room).  If you can see the beam in the "solution,"  it's not a true solution, it's a colloid or suspension!

We tested sugar water (solution), mint jelly (colloid), flour and water (suspension), tea (colloid!),
diluted milk (colloid), and Kool-Aid (colloid).  We used a laser pointer, but, before I found the laser, I used a flashlight covered in foil with a pin hole to let out a single beam of light.

If you're curious, whether something forms a solution, colloid, or suspension is dependent on particle size.  Only tiny particles form true solutions, and very large particles will settle.  Colloid particles re in between those sizes.

HT to Klenda for taking the pictures!