you can not measure gas of yeast
Carbon dioxide
Carbon Dioxide CO2
respirometer
respiromterrespirometer
It gives off carbon dioxide which proves that it respires.
because the water is boiling and you have killed all the yeast.
As anyone who bakes bread, or brew wines and beers will know, yeast needs a moist, warm environment in which there is dissolved liquid sugar available (not salt). The yeast cells rapidly multiply as the yeast feeds off the sugar, and gives off carbon dioxide gas and alcohol. It is the carbon dioxide gas that will inflate the balloon. Salt would probably kill off the yeast.
Yeasts give off gas as they consume and digest sugars. The bubbles of gas become trapped in the dough, causing the product to rise.
By fermentation, yeast converts carbohydrates to carbon dioxide and alcohol. Yeast has been used in baking for centuries as well as alcohol making.
Yeast feeds on the sugar present in the dough and releases a gas as a byproduct which makes the dough rise. Heat will initially cause the yeast to multiply rapidly, but then die off.
you can measure yeast by putting yeast in a warm climate
Yeast will produce gas if sugar, water, and warmth are available as long as the yeast is still alive. If it is too old or has been too hot and the yeast has died it won't create the gas.