Materials:
- Candy canes (other hard candy)
Safety:
Always have an adult help you when using hot or boiling water. The water and glasses can get very hot and may cause burns. Never taste or drink the mixtures – they’re for science only!
Experiment:
Line up four separate glasses and pour about a cup of the different liquids into each one (for the Alka-Seltzer tablet, use a cup of cold water and add the tablet). Place a candy cane in each of the cups, and after 5 or 10 minutes (be consistent), remove the canes. What happened to each one of the canes?
What’s happening?
Candy canes are made out of sugar, which has the chemical formula shown below. Notice all of the OH groups on the sugar.
Water has the formula H2O, but it is arranged like H–O–H (lots of OH groups). When looking at how much something dissolves in solution, we often say “like dissolves like”, which means that if two things are very similar, they will associate with each other. Water starts associating with all of the OH groups in sugar and completely surrounds those sugar molecules – and dissolves the sugar. By heating the water, the water molecules move faster and more quickly surrounds the sugar, and will dissolve the cane faster than the cold water. The Alka-Seltzer fizz also causes the molecules to move around faster, giving a similar effect. Oil has very little polarity and can be described as non-polar. It lacks OH groups that would like to associate with the polar OH groups in water – so there is very little dissolving occurring.
Extension:
What about other liquids such as ice water, soda, vinegar, vinegar with baking soda, salt water, sugar water, water with dishwashing soap? Would dissolving (dissolution) occur faster if the candy cane were crushed?
References:
https://thehomeschoolscientist.com/dissolving-candy-canes-experiment/
To view past “ChemShorts for Kids” activities, go to:
https://chicagoacs.org/ChemShorts.
