Science Buddies: "Ask an Expert"

My son started this project last Tuesday and as of today we have not seen any change. There are 9 total bottles. 3 are filled with manure and distilled water, 3 are filled with manure and mashed bananas and 3 are filled with raw onions and distilled water. There is a balloon on each bottle that is attached to the opening. The point to the project is the balloons will fill with air. As of today that has not happened. I looked on the trouble shooting section and we have done everything that it directed to do. Any help would be greatly appreciated.

Hi there,

Did you check to make sure that the balloons are tightly secured and that there are no holes?Also, what are the temperatures in the area in which you live? Part of the procedures mention that if the bottles are placed at cooler temperatures, it may take the balloons a little longer to inflate compared to being placed at warmer temperatures. In addition, did you notice large amounts of the biomass floating to the top of the bottle? Step 4 of the procedures mention that if enough of the biomass gets to the top of the bottle, it may prevent the biogas from getting into the balloons.

Try looking at some of these and see if they help. If other experts have other ideas, please chime in.

Good luck!

Connie