How to Make a Sugar Snake

This Sugar Snake demonstration was a chemistry experiment conducted during Science Week at SKH Lam Woo Memorial Secondary School on 5 April 2018.

How to make a sugar snake (aka black snake)
1. Put sand in a metal dish. The sand is there to serve as a kind of support and to make sure that there is an even distribution of heat.
2. Pour enough alcohol (or other kind of fuel like lighter fluid) onto the sand so that it becomes wet.
3. Put 1 part (e.g., 10 grams) of baking soda onto the sand. In our experiment, a paper tube was used to help shape the baking soda into a mound.
4. Cover the mound of baking soda with 40 grams of sugar. The exact amounts are not important. It is the ratio that is important. The ratio of sugar to baking soda should be 4:1.
5. Light the wet sand on fire.

The snake will slowly grow for around 10 to 20 minutes.

Processes:
Some of the sugar and baking soda combusts, producing water vapor and carbon dioxide gas.

Some of the material doesn’t have access to oxygen. Instead of combusting, it undergoes thermal decomposition, with the sugar producing solid carbon (which gives the snake its shape and color), and the baking soda producing sodium carbonate.

The CO2 and water vapor push these solids upwards, inflating the body of snake.

Credits:
Demonstrators: Yanty, Jessie and Agnes
Cameras: Kevin Yin
Music and editing: STR (aka longzijun)

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