OBJECT

To determine the conversion factor between Joules and calories.

Apparatus Required

• Rotating Cylinder 
• Stop Watch, 
• Lamp & Scale

THEORY

• Energy and heat were not initially seen to be measures of the same physical quantity. Thus the concepts were developed separately and their units are not equivalent. Energy can be measured in Joules (J) and heat in calories (cal). The accepted conversion is that one calorie equals 4.186 Joules. This experiment will attempt to obtain this result. 
• The apparatus is such that a spinning hub is able to just barely lift a mass, m, off the floor – see figure 1. It does this through the force of friction. Because there is relative motion between the string supporting the mass and the hub there will be work done: 

CONSTRUCTION

• Body: all metal body, a wheel driven by thread & provided with counter for noting the rotations.
• The unit is such that a metal cup rotates into another socket Brass cup of the same size that mechanical rotation energy is converted into Heat & can be read in the thermometer fitted .
• A side large wheel , when rotated with handle, it rotates the Lower pulley which is connected with shaft attached to the outer aluminum cylinder (inside which a brass hollow cup is fitted).
• This aluminum cylinder rotates swiftly and an counter is attached to the lower shaft for noting down the number of rotations per minutes using the stop watch.