Last week, the McMahon Lab hosted a table called “Build your own Lake” at the Wisconsin Science Festival’s Discovery Expo. We had a great time helping young scientists build their own Winogradsky columns, or “mini-lakes”! Visitors could choose either protein, sugar, or newspaper (or all three!) to add to their columns.
We sent the Winogradsky columns home with our visitors and asked them to observe the columns for four weeks. Little did we know that one of the columns would start to grow in spectacular fashion. Our sugar column is producing a lot of gas – and that gas is smelly! Parents, we apologize. If you have sugar column at home, make sure to vent the cap and let all that gas out. The gas and the smell are the results of a process called “fermentation.” This is how many bacteria digest sugar. Since we added several different types of sugar, there are likely multiple fermentation end products in the columns. These could include methane, ethanol, hydrogen, or lactic acid. Personally, we think ours smells most like lactic acid.*
The protein column is producing some gas as well, although nowhere near as much as the sugar. No signs of activity in the newspaper column yet, but we have high hopes for this one! Once it gets started, it should have some interesting effects.
*Smell can be an important method of scientific observation. Your nose is more sensitive to different compounds than any instrument currently invented. However, make sure to use the “wafting method” instead of directly sniffing your experiments.