The goal with our project, The Chai Fly Experiment, was to illustrate the principle which helps turn thermal energy into mechanical energy. Today, a similar principle is used to make hot air balloons fly. We started off by gathering all the materials we would need in order to conduct the experiment- tea bags with a string and label, a bowl, a lighter, scissors and a non-flammable flat surface. We removed the string, staple and label from the tea bag, cut off its top and poured its contents in the bowl. On a non-flammable surface, we unfolded it into the shape of a cylinder. Then, as we lit up the top of the tea bag, the air inside the cylinder was heated up. Air molecules took up more space as their movement became quicker. Air inside the tea bag cylinder got less dense as the air molecules were spread out. Warmer air with lesser density rose over cooler air with more density. The ashes of the tea bag were lifted by the force of the rise of the warmer air with lesser density- as a result of the experiment, the ashes of the tea bag proceeded to fly into the air.