Density Columns

Today, we had a density column competition.  Table groups worked together to apply the methods we learned yesterday to find the mass and volume of different types of liquid.  With those values, we could easily find the density for each liquid.  Then, we layered the liquids in the large graduated cylinder with the most dense liquid on the bottom.

A lot of groups had trouble with this activity.  Here are some things that could have given you trouble:

1.  Not making accurate measurements
     The students that measured the mass most accurately zeroed out the balance with a completely empty, dry graduated cylinder.
     The groups that measured the volume most accurately had each member of their group read the measurement, and they estimated to at least the nearest tenth of a milliliter.
     If either the mass or the volume measurement was off by even just a little bit, you had no chance at calculating an accurate density.

2.  Not doing the math correctly
     If you numbers weren't coming out they way you thought they should, my first suggestion was to make sure that you did mass divided by volume and not the other way around.

3.  Being careless when making the column
     The groups that had the most success stacking their liquids in the graduated cylinder used the pipettes (eye droppers) I supplied to drop the lighter liquids very carefully onto the more dense layers below them.


I know that this wasn't a very forgiving activity.  It only worked out if you did everything perfectly which frustrated many of you.  However, the groups that took their time and followed the procedures correctly were very successful.  Keep this in mind for future labs - I give you everything you need to succeed.  All you have to do is listen, follow instructions, and take your time.