Density Column Lab

Egg Drop Density Column Lab

It was midterm season once again and I was looking for a new lab for my Chemistry students to complete for their practical portion of the exam. I went hunting for a lab that would incorporate prior knowledge and showcase the student's ability to follow a lab procedure with little to no instruction from me, utilize the measuring skills that we have worked on all semester, demonstrate their understanding of laboratory safety rules, and to work independently. I found the answer in The Egg Drop Lab.

Because of time constraints (a two hour exam period that included a written portion) I set up the lab stations to include four liquid samples (I chose dark corn syrup, dishwashing liquid, vegetable oil, and rubbing alcohol into which I added blue food coloring) in graduated cylinders and indicated the empty mass of the glassware. I randomly filled the cylinders with differing volumes and the students had to calculate the density and predict what would happen if they added the four liquids to a test tube. Then they built a column to test their predictions. The lab procedure then asks them to predict where in the column water would settle and then to test that prediction. The next step was to determine the density of an egg and predict where in a column it would end up when dropped in. To minimize the amount of material used, I built the column using the student's input. The results are shown here. In addition I colored water with red food color and added it to the column before dropping in the egg.

What was really nice about this lab is the author designed this for an Earth Science course so it was an opportunity for me to have my students see the connection between what they have learned in Chemistry as it applies to the other sciences.