My Science School

The fact that objects dropped from a height fall to the ground, that the Moon is near enough to be seen from Earth, and that we do not float into the air when we are standing still has, of course, been known for thousands of years. What was not known was the reason for these phenomena. It was a British scientist, Isaac Newton, who, in 1666, put forward the idea that the same force — gravity — might be responsible for all these events. Gravity is a force of attraction caused by the huge mass of the Earth.

Four fundamental forces govern all interactions within the Universe. They are weak nuclear forces, strong nuclear forces, electromagnetism, and gravity. Of these, gravity is perhaps the most mysterious. While it has been understood for some time how this law of physics operates on the macro-scale – governing our Solar System, galaxies, and superclusters – how it interacts with the three other fundamental forces remains a mystery.

Naturally, human beings have had a basic understanding of this force since time immemorial. And when it comes to our modern understanding of gravity, credit is owed to one man who deciphered its properties and how it governs all things great and small – Sir Isaac Newton. Thanks to this 17th century English physicist and mathematician, our understanding of the Universe and the laws that govern it would forever be changed.

Objects may be electroplated for protection or to enhance their appearance. Very often, the object itself is made from a much cheaper material than the plating. Plating may protect the material underneath. Tin plate on steel cans stops the steel from corroding. Chromium Plating was once common on cars to prevent bumpers and headlights from rusting.

Electroplating is the process of using hydrolysis for plating one metal onto another. The process of electroplating is extensively used to modify the surface properties such as rust resistance and abrasion of objects. This process involves the use of an electric current, which is passed through the electrolyte (solution) containing two terminals called as electrodes. These electrodes are connected through a circuit with the power supply or battery. On passing an electric current through the circuit, the electrolyte in the solution splits up and some atoms from the metal are deposited on the top of one of the electrodes in the form of a thin layer. Metals like copper, gold, nickel, zinc, silver, cadmium, chromium, and tin are used in the electroplating process. This process is considered to be an important aspect in the production of electrical and electronic appliances, as it provides a coating on the surface of the metal of components used in these appliances. This helps in improving corrosion resistance, improves the conductivity of electricity, and enhances the solderability of the substrates. There are various applications of electroplating.

Mass plating is one of the types of electroplating that is used to plate a large volume of components in little to no time. To perform mass plating, a barrel is loaded with parts and then placed inside a container, which is filled with the coating material. Following this, the barrel is rotated to ensure that all the components inside the barrel are evenly coated for protection from corrosion. Mass plating is one of the most common types of electroplating and is one of the processes with the maximum applications. However, the mass plating process also brings parts in contact with one another, which can create an adverse effect on the coatings. So, another electroplating process can be used for components that require a high degree of aesthetic appeal. Following are the common examples of parts or components that undergo these types of electroplating: Bolts, Nuts, Screws, Washers, Pins and Electrical Connectors.

Rack plating is used to electroplate large, complex, and brittle parts that are tough to plate using other methods. In this process, parts are mounted to a “rack” and then immersed in a plating solution. This method provides uniform distribution of coating since the rack holds different parts that are plated at the same time. These types of electroplating processes are common in aluminum and zinc, and chrome and nickel are commonly used as plating solutions. Shape, size, and quantity of the parts must be considered before settling on this process.

In continuous plating items like tubes, wires, and strips are plated by running them continuously through a plating solution, one after the other. This process involves the even distribution of the coating material, such as zinc, aluminum, or tin, onto a metal like steel. It helps to enhance the corrosion resistance, appearance, wear, or other properties of a metal. Continuous plating provides even distribution of the coating and the electric current.

Electroplating uses electrolysis to deposit a thin layer of metal on another substance. The item to be plated is used as one electrode. Copper, silver, tin and chromium are often applied to surfaces in this way.

Electroplating is also known as electrode position. As the name suggests, the process involves depositing material using an electric current. This process results in a thin layer of metal being deposited onto the surface of a work-piece called the substrate. Electroplating is primarily used to change the physical properties of an object. This process can be used to give objects increased wear resistance, corrosion protection or aesthetic appeal, as well as increased thickness.

While electroplating may seem like advanced technology, it is actually a centuries-old process. The very first electroplating experiments occurred in the earth 18th century, and the process was officially formalized by Brugnatelli in the first half of the 19th century. After Brugnatelli's experiments, the electroplating process was adopted and developed across Europe. As manufacturing practices advanced over the next two centuries through the Industrial Revolution and two world wars, the electroplating process also evolved to keep up with demand, resulting in the process Sharretts Plating Company uses today.

The electroplating process uses an electric current to dissolve metal and deposit it onto a surface. The process works using four primary components:

Anode: The anode, or positively charged electrode, in the circuit is the metal that will form the plating.

Cathode: The cathode in the electroplating circuit is the part that needs to be plated. It is also called the substrate. This part acts as the negatively charged electrode in the circuit.

Solution: The electrodepositing reaction takes place in an electrolytic solution. This solution contains one or more metal salts, usually including copper sulfate, to facilitate the flow of electricity.

Power source: Current is added to the circuit using a power source. This power source applies a current to the anode, introducing electricity to the system.

Once the anode and cathode are placed in solution and connected, the power supply supplies a direct current (DC) to the anode. This current causes the metal to oxidize, allowing metal atoms to dissolve in the electrolyte solution as positive ions. The current then causes the metal ions to move to the negatively charged substrate and deposit onto the piece in a thin layer of metal.

As an example, consider the process of plating gold onto metal jewelry. The gold plating metal is the anode in the circuit, while the metal jewelry is the cathode. Both are placed in solution and DC power is supplied to the gold, which dissolves in solution. The dissolved gold atoms then adhere to the surface of the base metal jewelry, creating a gold coating.

Electrorefining, as the word suggests, is a way of purifying metals by using electrolysis. Copper can be purified by making the impure copper the anode in an electrolyte of copper sulphate. The cathode is made of pure copper. When an electric current is passed through the copper sulphate, positively charged copper ions from the anode are attracted to the cathode of pure metal. The impurities, which may be tiny amounts of other metals, such as mercury, gold and silver, fall to the bottom of the electrolyte.

Electro refining is one of a collection of electrochemical processes which are primarily concerned with the extraction of metals from their ores and or the subsequent refining of the metals to high purity.

The main advantages of electro refining processes are they are designed to handle a wide variation in the quality of the base scrap and conversely can provide a particularly high purity of end product material.

Electrochemical processing is used both in the primary extraction of metals from their ores and in the subsequent refining of metals to high purity. Both operations are accomplished in an electrolytic cell, a device that permits electrical energy to perform chemical work. This occurs by the transfer of electrical charge between two electrodes immersed in an ionically conducting liquid (electrolyte) containing metal dissolved as positive ions.

At the negatively charged cathode the metal cations acquire electrons (are reduced), and deposit as neutral metal atoms. At the positively charged anode there are two possible reactions, depending upon the type of cell. In an electrowinning cell the dissolution of the anode metal itself occurs. The more noble metals such as copper and zinc are electrolyzed from aqueous electrolytes, whereas reactive metals such as aluminum and magnesium are electrolyzed from electrolytes of their fused salts.

In an Electrorefining process, the anode is the impure metal and the impurities must be lost during the passage of the metal from the anode to the cathode during electrolysis, i.e. the electrode reactions are, at the anode: M ? Mn+ + ne- and at the cathode: Mn+ + ne- ? M.

Usually they are part of a larger operation to separate and recover pure metals from both scrap and primary ores. Therefore, the process must be designed to handle a variable-quality metal feed and lead to a concentration of all the metals present in a form which can be treated further. Electrorefining often provides a particularly high purity of metal.

Electrorefining processes using a molten salt or non-aqueous electrolyte are used and, indeed, are the subject of further development. This is due to the possibilities they offer for increasing current densities and refining via lower oxidation states not stable in water (e.g. refining of copper via Cu+ would almost halve the energy requirement). However, aqueous processes presently predominate due to their ease of handling, more developed chemistry and familiarity with aqueous process liquors and electrolytes.

Humphry Davy (1778-1829) was an English chemist who conducted some early experiments using electrolysis. This process offered a way of isolating metals from the compounds in which they are naturally found. As a result, Davy discovered potassium, sodium and calcium because he was able to separate the metals into their pure form.

Humphry Davy was a pioneer in the field of electrochemistry who used electrolysis to isolate many elements from the compounds in which they occur naturally.

Davy Electrolysis is the process by which an electrolyte is altered or decomposed by applying an electric current. In addition to his isolation of sodium, potassium and other alkaline earth metals, electrolysis enabled Davy to disprove the view proposed by French chemist Antoine-Laurent Lavoisier that oxygen was an essential component of all acids. When Davy decomposed hydrochloric acid (then known as muriatic acid), he found that it consisted solely of hydrogen and chlorine.

Humphry Davy (17 December 1778 – 29 May 1829) was a Cornish chemist and inventor, who is best remembered today for isolating, by using electricity, a series of elements for the first time: potassium and sodium in 1807 and calcium, strontium, barium, magnesium and boron the following year, as well as discovering the elemental nature of chlorine and iodine. Davy also studied the forces involved in these separations, inventing the new field of electrochemistry.

In 1799, he experimented with nitrous oxide and was astonished at how it made him laugh, so he nicknamed it "laughing gas" and wrote about its potential anaesthetics properties in relieving pain during surgery. He also invented the Davy lamp and a very early form of arc lamp. He joked that his assistant Michael Faraday was his greatest discovery.

When a metal reacts with oxygen, it forms a compound called an oxide. This happens on the surface of metals such as silver. As the oxide dulls the appearance of the metal, it is often rubbed off ornaments and jewellery, but in fact this simply presents a new surface of pure metal to the air to be oxidized. However, some metals, such as aluminium, are deliberately coated, by means of electrolysis, with a layer of their oxide. This process is known as anodization. It protects the metal underneath from oxidizing further.

Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum is ideally suited to anodizing, although other nonferrous metals, such as magnesium and titanium, also can be anodized.

The anodic oxide structure originates from the aluminum substrate and is composed entirely of aluminum oxide. This aluminum oxide is not applied to the surface like paint or plating, but is fully integrated with the underlying aluminum substrate, so it cannot chip or peel. It has a highly ordered, porous structure that allows for secondary processes such as coloring and sealing.

Anodizing is accomplished by immersing the aluminum into an acid electrolyte bath and passing an electric current through the medium. A cathode is mounted to the inside of the anodizing tank; the aluminum acts as an anode, so that oxygen ions are released from the electrolyte to combine with the aluminum atoms at the surface of the part being anodized. Anodizing is, therefore, a matter of highly controlled oxidation the enhancement of a naturally occurring phenomenon.

Cathodes and anodes are electrodes. These are carbon or metal rods that are connected to an electric current. When they are placed in an electrolyte, current can pass through the liquid from one electrode to the other, so completing the circuit. The cathode has a negative electrical charge and the anode has a positive electrical charge. Ions in the electrolyte are being held together because they have opposite electrical charges, which attract each other. These bonds are broken because the ions with positive charges are more strongly attracted to the negative charge of the cathode than they are to the negative charge of the ions with which they are bonded. In the same way, negatively charged ions are attracted to the anode.

Cathode

When we talk about cathode in chemistry, it is said to be the electrode where reduction occurs. This is common in an electrochemical cell. Here, the cathode is negative as the electrical energy that is supplied to the cell results in the decomposition of chemical compounds. However, it can also be positive as in the case of a galvanic cell where a chemical reaction leads to the generation of electrical energy.

In addition, a cathode is said to be either hot cathode or a cold cathode. A cathode which is heated in the presence of a filament to emit electrons by thermionic emission is known as a hot cathode whereas cold cathodes are not heated by any filament. A cathode is usually flagged as “cold” if it emits more electrons compared to the ones generated by thermionic emission alone.

Anode

In the most basic form, an anode in electrochemistry is the point where an oxidation reaction occurs. Generally, at an anode, negative ions or anions due to its electrical potential tend to react and give off electrons. These electrons then move up and into the driving circuit.

If we take a galvanic cell, the anode is negative in nature and the electrons mostly move towards the external part of the circuit. In an electrolytic cell, it is again positive. Additionally, an anode can be a plate or wire having an excess positive charge.

An electrolyte is a liquid that can conduct an electric current. A metal may become an electrolyte if it is molten (melted) or dissolved in another liquid. Water can also conduct an electric current. That is why it is very dangerous to touch an electric socket with wet hands.

An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent. Electrically, such a solution is neutral. If an electric potential is applied to such a solution, the cations of the solution are drawn to the electrode that has an abundance of electrons, while the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current. This includes most soluble salts, acids, and bases. Some gases, such as hydrogen chloride, under conditions of high temperature or low pressure can also function as electrolytes. Electrolyte solutions can also result from the dissolution of some biological (e.g., DNA, polypeptides) and synthetic polymers (e.g., polystyrene sulfonate), termed "polyelectrolytes", which contain charged functional groups. A substance that dissociates into ions in solution acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, magnesium, and phosphate are examples of electrolytes.

In medicine, electrolyte replacement is needed when a person has prolonged vomiting or diarrhea, and as a response to strenuous athletic activity. Commercial electrolyte solutions are available, particularly for sick children (such as oral rehydration solution, Suero Oral, or Pedialyte) and athletes (sports drinks). Electrolyte monitoring is important in the treatment of anorexia and bulimia.

Some compounds can be separated into individual elements by passing an electric current through them when they are in a liquid state. This process is called electrolysis. For this to happen, the compound must be able to conduct electricity, and its elements must be held together by ionic bonds. Many industrial processes use electrolysis, especially those concerned with purifying metals or applying thin layers of metal to other objects.

Electrolysis is a way of separating a compound by passing an electric current through it; the products are the compound’s component ions. In order to predict the products of electrolysis, we first need to understand what electrolysis is and how it works. Electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. It uses a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is very important commercially as a stage in the separation of elements from naturally occurring sources, such as ores, using an electrolytic cell.

• An electrolyte: a substance containing free ions, which are the carriers of electric current in the electrolyte. If the ions are not mobile, as in a solid salt, then electrolysis cannot occur.


• A direct current (DC) supply: provides the energy necessary to create or discharge the ions in the electrolyte. Electric current is carried by electrons in the external circuit.


• Two electrodes: an electrical conductor that provides the physical interface between the electrical circuit providing the energy and the electrolyte.

Materials that allow electric currents to pass through them are called conductors. One of the best conductors that are fairly cheap to obtain is copper, which is why many electric cables and wires are made of this metal.

A conductor is a material which electricity, heat or sound can flow through. An electrical conductor conducts electricity. The ability to conduct electricity is called electrical conductivity.

Most metals, like iron and copper, are electrical conductors. These metals are used to make wires to carry electric current. Plasma is an excellent conductor of electricity and is used for many purposes but metals are more used. Some materials are semiconductors. This means that electricity can flow through them, but not very well. Some materials are resistors. This means that they make it very hard for electricity to flow through them.

A material that stops electric current is called an insulator (electricity). Wires are covered with insulators like plastic to stop the electricity from leaving the wire. Some materials when really cold are superconductors. They offer no resistance at all to the flow of electricity. A conductor's resistance tends to get higher when the temperature also gets high.

An insulator is the opposite of a conductor. It is a material that will not allow electrical current to run through it because its electrons are not free to move. Plastic is a very good insulator. That is why it is used to cover copper wire. The wire can then safely conduct electricity along its length without allowing it to come into contact with other conductors.

An electrical insulator is a material that does not easily allow flow of electricity through an electric current. Materials typically used to insulate include rubber, plastic and glass. In transformers and electric motors, varnish is used. Insulating gases such as Sulfur hexafluoride are used in some switches. Wires that carry electric currents are usually insulated so the electricity goes to the right place.

Insulator can mean not only the material but things that are made of that material. They are made of various materials such as: glass, silicone, rubber, plastic, oil, and wood, dry cotton, quartz, ceramic, etc.

The type of insulator will depend on the uses. Insulators have high electrical resistivity and low conductivity. The insulators prevent the loss of current and make the current more efficient by concentrating the flow.

• The pin insulator is the earliest developed insulator. Pin type insulators can have up to three parts, depending on the amount of voltage.


• The suspension insulator is for voltages above 33KV. Multiple insulators are connected in series.


• The strain insulator is the same as a suspension insulator but it is used horizontally, whereas the suspension insulator is used vertically. The strain insulator is used to relieve the line of excessive tension, which happens when there is dead end of the line or sharp curve. 

A circuit is a path along which an electric current can flow. Each part of the circuit must be connected to the next, and each must be able to conduct electricity. In a series circuit, there is only one path for the current to follow, and it passes through each component of the circuit in turn. If one component fails, the current will no longer be able to flow. Christmas tree lights are usually connected to each other in series. When one bulb blows, the circuit is broken and all the lights go out.

Instead of being connected in a series circuit, the same components could be connected in a parallel circuit. In this kind of circuit, there is more than one pathway for the electrical current to flow along.

An electric circuit includes a device that gives energy to the charged particles constituting the current, such as a battery or a generator; devices that use current, such as lamps, electric motors, or computers; and the connecting wires or transmission lines. Two of the basic laws that mathematically describe the performance of electric circuits are Ohm’s law and Kirchhoff’s rules.

Electric circuits are classified in several ways. A direct-current circuit carries current that flows only in one direction. An alternating-current circuit carries current that pulsates back and forth many times each second, as in most household circuits. (For a more-detailed discussion of direct- and alternating-current circuits, electricity: Direct electric current and electricity: Alternating electric circuit.).) A series circuit comprises a path along which the whole current flows through each component. A parallel circuit comprises branches so that the current divides and only part of it flows through any branch. The voltage, or potential difference, across each branch of a parallel circuit is the same, but the currents may vary. In a home electrical circuit, for instance, the same voltage is applied across each light or appliance, but each of these loads draws a different amount of current, according to its power requirements. A number of similar batteries connected in parallel provide greater current than a single battery, but the voltage is the same as for a single battery. 

The network of transistors, transformers, capacitors, connecting wires, and other electronic components within a single device such as a radio is also an electric circuit. Such complex circuits may be made up of one or more branches in combinations of series and series-parallel arrangements.

A lightning conductor is a metal rod that is placed so that it points upwards above the highest point of a tall building. If lightning does strike the building, it is the lightning conductor, not the building itself, that the spark hits. The electrical charge then runs harmlessly down the lightning conductor to Earth.

Lightning rods were originally developed by Benjamin Franklin. A lightning rod is very simple -- it's a pointed metal rod attached to the roof of a building. The rod might be an inch (2 cm) in diameter. It connects to a huge piece of copper or aluminum wire that's also an inch or so in diameter. The wire is connected to a conductive grid buried in the ground nearby.

 

The purpose of lightning rods is often misunderstood. Many people believe that lightning rods "attract" lightning. It is better stated to say that lightning rods provide a low-resistance path to ground that can be used to conduct the enormous electrical currents when lightning strikes occur. If lightning strikes, the system attempts to carry the harmful electrical current away from the structure and safely to ground. The system has the ability to handle the enormous electrical current associated with the strike. If the strike contacts a material that is not a good conductor, the material will suffer massive heat damage. The lightning-rod system is an excellent conductor and thus allows the current to flow to ground without causing any heat damage.

Lightning can "jump around" when it strikes. This "jumping" is associated with the electrical potential of the strike target with respect to the earth's potential. The lightning can strike and then "seek" a path of least resistance by jumping around to nearby objects that provide a better path to ground. If the strike occurs near the lightning-rod system, the system will have a very low-resistance path and can then receive a "jump," diverting the strike current to ground before it can do any more damage.

As you can see, the purpose of the lightning rod is not to attract lightning -- it merely provides a safe option for the lightning strike to choose. This may sound a little picky, but it's not if you consider that the lightning rods only become relevant when a strike occurs or immediately after a strike occurs. Regardless of whether or not a lightning-rod system is present, the strike will still occur.

If the structure that you are attempting to protect is out in an open, flat area, you often create a lightning protection system that uses a very tall lightning rod. This rod should be taller than the structure. If the area finds itself in a strong electric field, the tall rod can begin sending up positive streamers in an attempt to dissipate the electric field. While it is not a given that the rod will always conduct the lightning discharged in the immediate area, it does have a better possibility than the structure. Again, the goal is to provide a low-resistance path to ground in an area that has the possibility to receive a strike. This possibility arises from the strength of the electric field generated by the storm clouds.

Static electricity is what sometimes makes a nylon jumper crackle and spark in dry weather. Or you may, get a small electric shock from a metal surface after walking across a carpet made of artificial fibres. Rubbing something made of amber or plastic can cause it to pick up electrons from your clothes or hair, giving them a positive charge. If you then touch something with a slightly negative charge, a small spark may fly across just before you touch it, or, if it is light, the oppositely charged object may be attracted to you.

Static electricity can be a nuisance or even a danger. The energy that makes your hair to stand on end can also damage electronics and cause explosions. However, properly controlled and manipulated, it can also be a tremendous boon to modern life.

“Electric charge is a fundamental property of matter,” according to Michael Richmond, a physics professor at the Rochester Institute of Technology. Nearly all electric charge in the universe is carried by protons and electrons. Protons are said to have a charge of +1 electron unit, while electrons have a charge of ?1, although these signs are completely arbitrary. Because protons are generally confined to atomic nuclei, which are in turn imbedded inside atoms, they are not nearly as free to move as are electrons. Therefore, when we talk about electric current, we nearly always mean the flow of electrons, and when we talk about static electricity, we generally mean an imbalance between negative and positive charges in objects.

Electricity is a form of energy. Electricity is the flow of electrons. All matter is made up of atoms, and an atom has a center, called a nucleus. The nucleus contains positively charged particles called protons and uncharged particles called neutrons. The nucleus of an atom is surrounded by negatively charged particles called electrons. The negative charge of an electron is equal to the positive charge of a proton, and the number of electrons in an atom is usually equal to the number of protons. When the balancing force between protons and electrons is upset by an outside force, an atom may gain or lose an electron. When electrons are "lost" from an atom, the free movement of these electrons constitutes an electric current.

Electricity is a basic part of nature and it is one of our most widely used forms of energy. We get electricity, which is a secondary energy source, from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources. Many cities and towns were built alongside waterfalls (a primary source of mechanical energy) that turned water wheels to perform work. Before electricity generation began slightly over 100 years ago, houses were lit with kerosene lamps, food was cooled in iceboxes, and rooms were warmed by wood-burning or coal-burning stoves. Beginning with Benjamin Franklin's experiment with a kite one stormy night in Philadelphia, the principles of electricity gradually became understood. In the mid-1800s, everyone's life changed with the invention of the electric light bulb. Prior to 1879, electricity had been used in arc lights for outdoor lighting. The lightbulb’s invention used electricity to bring indoor lighting to our homes.