Although we may not admit it, all humans fart or pass some gas. In this activity, learners make their own model to mimic food passing through intestines and discover what releases gas. Learners mash up a banana and monitor how much gas is released over time using a bottle and balloon. Extension ideas are included to compare fatty foods (like avocados) and foods high in starch and sugar (like fruits) in the model. Step-by-step instructions are included with photos. Activity guide includes a "What's going on?" explanation and connections to relevant science concepts like digestion, bacteria beneficial to our health, and the make-up of gasses in our intestines.