My ChemClub students came to my room for a holiday celebration today. We made a batch of seafoam candy. There are many recipes available, but they are all basically the same. I premeasured a cup of white sugar, a cup of karo syrup (we used light but many recipes call for dark) and 1 Tbsp of white vinegar. We used a hotplate in my classroom and heated these three ingredients in a large stockpot (needs to be larger than the ingredient amounts might imply since the acid/base reaction creates a lot of carbon dioxide bubbles) while stirring for about 15 minutes. We used a candy thermometer and when the mixture reached 307°F, we removed the stockpot from the hotplate and quickly added a Tbsp of baking soda while stirring vigorously. As soon as we got the resulting bubbles from the classic vinegar and carbon dioxide reaction, we poured the mixture onto two cookie sheets. We allowed the candy to cool for about 30 minutes while we made an Elephant Toothpaste Christmas Tree that I had seen online. I used a 500 mL flask sitting on top of a 500 mL beaker inside a tub to collect the mess. The flask gave the tree a nice holiday tree shape.
We took a break and ate the Seafoam candy along with other snacks students brought to share. We then used JCE Classroom Activity #89 to create marbled gift tags. Check out the ACS ChemClub page for numerous holiday ideas that you can still find time for.
