Electric Charges, Energy Sources, and Power Generation
Electric Charges: Positive and Negative
There are two kinds of electric charges: positive charge (+) and negative charge (-).
- The closer two objects carrying the same sign are, the more they repel each other.
- The closer two objects with different signs of charge are, the more they attract each other.
- A body with no electrical charge has the same number of protons as electrons.
- A body with a negative electric charge has gained electrons.
- A body with a positive electric charge has lost electrons.
Conductors and Insulators
- Conductors are materials that allow electrons to move easily.
- Insulators are materials that do not allow electrons to move easily.
Electrostatic induction is the separation of positive and negative charges in a conductor, caused by the presence of a charged body.
Fossil Fuels
Natural Gas
Natural gas is a fossil fuel consisting mainly of methane gas. It is the least polluting fossil fuel.
Oil
Oil is a fossil fuel consisting of a mixture of many different substances called hydrocarbons. Burning it releases a lot of energy.
Power Plants and Energy Generation
A power plant is a facility that produces energy using water vapor. The water is evaporated at a high temperature and pressure, which moves a steam turbine. This turbine is connected to the coils of an alternator, which rotate within a magnetic field and produce electricity.
Hydropower
Hydropower utilizes water stored in a reservoir located at a high elevation. This water possesses gravitational potential energy. When released, the water moves turbines very quickly, which, in turn, power electricity generators.
Energy from the Sea
Tidal power plants use a barrier placed in an estuary to store water. This stored water is then used to turn a turbine.
The power of a receiver is calculated as: Power = Voltage x Intensity (P = VI)
Energy: Transformations and Conservation
Energy is the cause of the changes occurring around us.
Types of Energy Transfer
- Work: Producing movement or deformation of an object by applying a force.
- Heat: Raising the temperature of objects, potentially causing changes in state or chemical transformations.
Principle of Conservation of Energy
Energy cannot be created or destroyed; it only transforms from one form to another.
Units of Energy
A joule is the work done by a force of 1 newton as it travels 1 meter in the same direction. 1J = 1N x 1m
Potential and Kinetic Energy
The energy stored in the body from food is called gravitational potential energy. When gravitational potential energy is converted into energy of motion, it is called kinetic energy.
Renewable and Non-Renewable Energy Sources
Renewable energy sources are clean energy sources distributed throughout the world. Their main disadvantage is that they generate a relatively small amount of energy per unit of time.
Non-renewable energy sources are generally not significant polluters, as they do not generate polluting waste. They have the advantage of having great power, producing a large amount of energy per unit of time. They account for 90% of the world’s energy.
Fuels
A fuel is a substance that, when combined with oxygen, gives off heat energy.
Fossil Fuels
Fossil fuels are substances formed by the transformation of organic matter from creatures that lived millions of years ago.
Coal
Coal is a fossil fuel composed of carbon with sulfur and nitrogen impurities.