Main experiment: - With the help of a plastic spoon or spatula some yeast is to be placed in a weigh boat on the balance and 10 grams of yeast is to be measured out. Next, using a separate weigh boat, 5, 10, 15, 20, 25, 30 grams of sugar are to be measured out. 50 gms of dough is to be kneaded by using same proportions of water and flour in separate weigh boats. Subsequently, a mixture of 10 grams of yeast and equal amounts of dough, thoroughly mixed, are to be placed in 7 balloons. The contents of these balloons are to thoroughly mixed once again. Then a piece of string is to be used in order to tie the balloon just above the mixture in it. This is to ensure that there is no air inside it. After this the balloon must be pressed gently from the sides in order to expel any air left inside and a tight double knot is to be tied with a piece of string. The excess string is to be left on the balloon. The rubber band is to be knotted as closely as possible to the knot in the string. These balloons are to be placed on ice in order to prevent fermentation.
Similarly, all 7 balloons are to be prepared using the 0,5,10,15,20,25,30 grams of sugar. These balloons are to be labeled as A,B,C,D,E,F,G respectively. Next, their volume is to be determined using the water displacement method. In this method, a 600 ml beaker or large jar is to be placed in an overflow pan. This container is to be filled to the very top with tap water. The balloon is to be completely submerged in the water by pushing it under the water and allowing the water to spill over the sides and into the pan. This process is to be stopped when the fingers touch the water. The water in the pan is the volume of the balloon.
This is to be measured carefully in a graduated cylinder and recorded on a data table. After this the balloon is to be put back in the ice immediately. It is sufficient to measure a single balloon’s