Using your Valentine’s Day chocolates to demonstrate density

Before your students arrive, unwrap a Snickers® candy bar and a 3 Musketeers® candy bar (any size is acceptable). Have a large, transparent container filled with water set up in the front of the classroom. Drop the two, seemingly identical, candy bars into the water and let the discussion begin.

Clear glass of water with two squares of chocolate, one floating, the other one has sunk to the bottom.

Some possible classroom discussion ideas are:

  • Would a king-size candy bar float or sink?
  • Have students calculate the density. How might they determine the volume of the bar?
  • Is the chocolate bar homogeneous or heterogeneous?
  • Would the bar that sank float if cut into two pieces?

All this from a beaker of water and two candy bars — and if you have any chocolate samples left over to share, students will love chemistry even more this Valentine’s Day. You might even want to experiment with some chocolate hearts.

This activity was taken from a blog called Science Matters written by Karen Hickland. Karen has set up the blog to help provide quality science education; breaking down the misconceptions that keep students and teachers from believing that science is fun and accessible to everyone.