With the galileo thermometer working on the principles of changing densities in water I needed to figure out how to calculate a few things.
How to calculate the shape of the bulb, the size it must be?
What is the density of water and glass?
To do this I got some help from a physicist Mervin Rose.
From my chat with Mervin I got this little A4 sheet on it was basically how I need to calculate the bulb. The bulb must be a shape that dispenses the water evenly (circular would be easiest) as for sizes the bulb must be made to two parts air one part glass. This basically means that the volume of the air on the inside must be double that of the volume of the glass on the outside to make it buoyant.