Energy & Heat

ENERGY & HEAT

An object possesses energy if it has the capacity to do work.

ALL energy is either potential or kinetic. While potential energy cannot be observed, it is the amount of energy an object has due to its position or shape. Kinetic energy is the energy of an object due to the motion of an object. Potential energy can be classified even further. Gravitational potential energy is held in an object due to the object's gravitational attraction to another object. The second type of Potential energy is elastic potential energy, energy that is stored due to the application of force that deforms an elastic object, When the force is removed from the object, the energy is released, & the object returns to its original state. An object's mechanical energy is the sum total of the object's gravitational potential energy, elastic potential energy, & kinetic energy.

Energy can be transformed from one type to another, the law of conservation of energy states that energy cannot be created or destroyed, but can be changed from one form to another. Energy can come in many forms: light, sound, electricity, & heat.

Either the transfer of kinetic energy from an energy source to a medium or object or the transfer of Kinetic energy from one medium or object to another. Heat transfer can occur as conduction, Convection, & radiation. It is important to note that energy will always move from a hotter object to a cooler object. An exothermic reaction occurs when heat is generated in a system and released to its surroundings, while an endothermic reaction is one that absorbs heat from its surroundings.

The scale for measuring heat is temperature or the kinetic energy of the molecules in an object, temperature is measured using either Celsius, where water will freeze at 0° and will boil at 100°, or Fahrenheit, where water will freeze at 32° and water will bail at 212° under normal conditions. The particles can stop moving altogether if the temperature is low enough, & is referred to as absolute zero, 0° Kelvin, or -459.67° F, and is physically impossible to reach. Kelvin is a third scale of measurement for temperature, where water will freeze at 273.15 Kelvins & boil at 373.15 Kelvins.

The amount of energy required to raise the temperature of 1 kg. of a substance by 1°C is referred to as specific heat. Heat can also move through an object via either convection or conduction. Convection is a process that occurs in liquids and gasses when molecules carrying energy rise before eventually cooling & sinking, thus producing a continuous cycle of heat transfer; this cyclic process is known as convection current. Conduction is a process of heat energy transfer that occurs when particles are in direct contact and have different temperatures.

Fossil fuels are nonrenewable, natural fuels comprised of hydrocarbon deposits that are formed from the remains of living organisms. Coal, oil, and natural gas are examples of fossil fuels, which are the primary source of energy in the United States despite all the environmental problems they cause. Another source of energy is nuclear power, a nonrenewable source of energy associated with nuclear fission. Despite the low cost associated with nuclear energy, there are many concerns with widespread use. Primarily, concerns regarding the radioactive waste produced by the fission process, coupled with the potential for tragic nuclear meltdowns as seen in Chernobyl, Ukraine, and Fukushima, Japan, have halted the adoption of nuclear power.

Renewable energy sources exist, such as Hydroelectric power, which produces energy via the systematic placement of river dams that spin turbines to produce electricity. Solar power is a form of power that involves converting the sun's rays into electricity, usually through the use of photovoltaic cells. Wind power, which involves harnessing the Kinetic energy of the wind to generate electrical power, usually through turbines. Photovoltaic cells - generally composed of treated silicon & used to convert solar energy to electrical energy.