Friday, January 25, 2013

Marshmallow and Cherry Density Layer Cake

By Susan Wells, Steve Spangler Science

This experiment mixes a little kitchen science, candy science and physical science. And the end result of this activity is delicious.


The cherries and marshmallows in this cake switch places, thanks to density.

To make a three-layer density cake, you will need the following materials:
  • Cake mix (flavor is up to you, we used Devil’s Cake)
  • Bag of small marshmallows
  • 2 cans of cherry pie mix with whole cherries
  • Eggs
  • Oil
  • Water
  • Clear glass cake pan
Instructions:
  1. Prepare cake batter per box directions.
  2. Spray the bottom of the cake pan.
  3. Cover the bottom of the pan with marshmallows.
  4. Pour cake batter over the marshmallows.
  5. Layer the cherry pie filing on top of the batter. Do this quickly, as the marshmallows will start to float up almost immediately.
  6. Bake the cake according to box directions.
As the cake bakes, the marshmallows and cherries will switch places. As the marshmallows rise to the top, they will melt and become gooey. As the cherries fall to the bottom, they will disappear, along with the pie filing.

How does this work?
The answer lies in density. Density is defined as mass divided by volume or the amount of stuff in a certain amount of space. Marshmallows are a mixture of sugar and gelatin, puffed up with air. They are much less dense than the cherries. The marshmallows are less dense than the cake batter too, so the marshmallows rise up through the batter. The cherries are more dense than the batter, so they fall to the bottom.

This experiment was developed by former teacher and Story Time Slime speaker Julie Gintzler as a 100-day activity with her class. She lined 100 marshmallows on the bottom of the cake pan as part of the celebration.

Susan Wells is a social media specialist and blogger for Steve Spangler Science. She is a mother of two girls who loves to find the learning in everything. Susan also runs the science fair and science clubs at her girls’ school. Follow Susan on Twitter and check out all of Steve Spangler’s educational boards on Pinterest and scientific posts on Facebook.

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