# Summative Report on the Solar Cooker

Essay by hell_dragonJunior High, 8th grade January 2007

SUMMATIVE REPORT

1.0Conservation of Energy

Energy is defined as the ability to do work. It exists in various forms and may be transformed from one type to another. However, these energy transformations are constrained by the Conservation of Energy principle. It can be interpreted as "Energy can neither be created nor destroyed, it can only be converted from one form to another" An alternative is to say that the total energy of an isolated system remains constant.

2.0First Law of Thermodynamics

The first law of thermodynamics is the application of the conservation of energy principle to heat and thermodynamic processes. The defining equation can be given as:

ÃÂU = Q - W

Where ÃÂU = change in internal energy, Q = heat added to the system and W = work done by the system. Assuming that no work is done and no energy is lost to the surroundings, we can apply this equation as:

Change in internal energy (temperature) of liquid X = Heat received from the sun

3.0Heat

Heat is measured in joules (J) and is the thermal energy that is transferred from a hotter to a cooler object. When we heat an object, we are supplying energy to it. From the law of conservation of energy, we know that the heat does not disappear; instead, it is being transformed into the internal energy of the molecules of the object. The internal energy of the molecules is in two forms: kinetic and potential energy. Heat is then a measure of the change in the total internal energy of a body.

4.0Solar Energy

We assume that solar energy reaches the Earth's upper atmosphere at an intensity of 1366 watts per square meter (W/m2). Our solar cooker will amplify solar energy to boil liquid X.

5.0Boiling Point of liquid X...