Early Electrical Devices, Charge, and Energy Principles
Leyden Jar: Early Electricity Storage
In 1746, the scientist Peter van Musschenbroek at Leiden University in Holland managed to store electricity in a bottle of water. To do this, he passed a metal rod through the cork and inserted it into the water. The rod had a hook on the top, to which he approached an electrically charged body. In one of his experiments, he received an electric shock when bringing his hand to the rod: he had successfully managed to store electricity. Shortly thereafter, this device, known as the Leyden jar, was perfected by the English scientist William Watson, who wrapped the bottle with tin foil, and the Frenchman Jean-Antoine Nollet, who replaced the water with tin foil. This device’s shock became so strong that the Leyden jar was used frequently in public demonstrations showcasing the great power of electricity.
Torsion Balance: Measuring Force
It consists of a rod that hangs by a glass thread that can be twisted. If the rod rotates, the thread tends to return to its original position. Finally, an equilibrium is reached at an angle relative to its initial position. This angle is proportional to the force that twists the thread, which makes this device a very sensitive mechanism for measuring forces.
Electroscope: Detecting Electric Charge
It is an old and simple device used, even today, to detect electrical charge. It consists of a metal bar ending in a small sphere at the top and two thin flakes of metal (usually gold leaf) at the bottom. This bar is isolated from the outside by a glass container. When the metal sphere is touched with a charged body, the gold leaves repel each other, as they become charged with electricity of the same sign. Using this, we can not only determine if a body is electrified or not, but also estimate the charge, as the angle of separation of the leaves is directly proportional to the charge supplied. To this end, a graduated scale is often added. The electroscope can be used in two ways: by touching the upper sphere with the electrically charged body (conduction), or by approaching it without touching (induction).
Understanding Electric Charge in Matter
Objects may not always appear to have electricity, but through electrification experiences, as well as natural phenomena such as storms, it is observed that electrical effects manifest. We also know that all matter contains particles carrying electric charge. Hence, we can state the following: electric charge is a fundamental property of matter, and electrification is due to the transfer of electrons from one body to another. A body becomes negatively charged when it has an excess of electrons and positively charged when it has lost electrons. The total amount of electric charge is conserved.
Fundamentals of Energy and Its Sources
Energy is the capacity of material systems to produce change. Key types include:
- Mechanical Energy: Related to motion (kinetic energy) and the position of bodies (potential energy).
- Internal Energy: Due to the thermal motion of particles, their arrangement, chemical bonds, and the energy of atomic nuclei.
- Radiant Energy: Energy received in the form of electromagnetic radiation (visible or invisible), such as light, radio waves, microwaves, etc.
Energy is not created nor destroyed, only transformed.
Nuclear Fission Energy
Nuclear power plants are, in fact, thermal power plants where the fuel used is not coal or gas, but radioactive metallic elements such as uranium (U) or plutonium (Pu). They do not burn anything in the conventional sense, so they typically do not emit combustion pollutants into the atmosphere. During fission, uranium atoms are transformed into different, lighter, and more stable nuclei, releasing an enormous amount of energy.
Renewable Energy Sources
We say that an energy source is renewable if its rate of regeneration is equal to or greater than its rate of consumption. On a human timescale, until the Sun finishes radiating energy, these sources can be considered inexhaustible.