Hearts Bobbing

For those who missed the Hearts Bobbing instructions on ParentMap and Parenting.com, here is the full experiment.

To make conversation hearts bob, drop them in a bottle of club soda. As the carbon dioxide in the soda forms bubbles on the hearts, the hearts bob to the surface, only to sink again when the bubbles come off. If you put the lid back on the bottle, the hearts will bob for a few minutes. Once they reach the top and start to stay there, gently shake or tap the bottle to knock the bubbles off and put the hearts back in motion. You can also do this experiment by pouring the soda into a cup and adding the hearts, or by using clear soda pop instead of club soda.

A version of this photo appeared in the book Candy Experiments,
and is copyrighted by Andrews McMeel Publishing.

Dancing Valentine Hearts Candy Experiment

Bubbles attach to conversation hearts, making them bob up and down in club soda.



What you need:

• Conversation hearts such as Brach's or Sweethearts
  (avoid Brach's Heart2Heart candies)
• Bottle of clear soda pop or club soda

What to do:

1. Open the bottle of club soda
2. Drop the hearts into the bottle and put the lid back on.
   (Variation: pour the soda into a glass and drop in the hearts.)
3. Watch the hearts rise to the surface and then sink.
4. Tap or shake the bottle to make the hearts sink again.
5. If the hearts don't float, break or chop a few hearts into small pieces and try again.

What’s happening:
The rough surface of a conversation heart provides perfect places for bubbles to form (nucleation sites). When the heart is dropped in club soda, the carbon dioxide dissolved in the water forms bubbles that make the hearts rise. If you shake the glass to knock the bubbles off of the hearts, the hearts sink again.



From the book Candy Experiments by Loralee Leavitt