Video #20:  Black Ink is Not Really Black

Handout #75 introduced

learned that washable black ink is made of three different colors.  Its component colors are magenta/red, yellow and blue.  You were able to see those beautiful colors because we water passed through that black ink dot on its way up a strip of chromatography paper.  

But, why did the blue ink travel farthest and magenta/red ink the shortest . . . and yellow somewhere in the middle?  It has to do with the polar strength (polarity) of each of the three ink molecules. Water is a magnet (polar molecule) and the component color are magnets, too.  But each color has a different polar strength.  The strongest magnet (highest polarity) will ride along the furthest.  The ink with lowest polarity will travel the shortest distance.  It will be the first color left behind.  What you were observing was really just magnets riding with magnets.

Video #19:  Getting Water Busy

So, why did we use 5% saltwater to examine the different types and colors of ink?

Video #17:  Water is a Polar Molecule

Water molecules can be thought of as tiny magnets.  Well then, what is a polar molecule?   

Also . . . Salt (NaCl) does not dissolve in water.  What?  Nope, it is said to dissociate in water.  This means that water molecules separate  salt into its Na+ and Cl- ions.  It separates and surrounds those ions.

Sugar dissolves in water.  Water molecules separate and surround the the entire sugar molecule.