Sports: Volleyball

History of Volleyball
The game of volleyball, originally called "Mintonette", was invented in 1895 by William G. Morgan. He decided to blend the elements of basketball, baseball, tennis and handball to create a game for his classes of businessmen which would demand less physical contact than basketball. The first volleyball net which was borrowed from tennis was 6 feet 6 inches above the floor. Team volleyed the ball back and forth across the net until one team missed. The first competitive game of volleyball was played July 7, 1896. 

Volleyball is a sport played by two teams on a playing court divided by a net. The object of the game is to send the ball over the net in order to ground it on the opponent's court, and to prevent the same effort by the opponent. The team has three hits for returning the ball (in addition to the block contact). The ball is put in play with a service, hit by the server over the net to the opponents. The rally continues until the ball is grounded on the playing court, goes 'out' or a team fails to return it properly. 

  Rules in Volleyball
Some rules include:

• Each team must consist of six players on the court. Usually three persons are in the front row and three in the back row. 
• Each team is allowed to have a maximum of three touches before hitting the ball over the net.
• The net must be under eight feet (2.43 m) for men and under seven feet (2.24 m) for women. 
• Players are not allowed to hit or block the opponent's serve.
• Players are not allowed to catch, hit or throw the ball.
• No player can ever make contact with the ball twice in succession, and the ball cannot be caught or carried over the net. 
• The ball is ruled out if it lands outside of the boundary lines (without touching the opponents). 

Volleyball Court

 Skills in Volleyball
Skills are essential when playing volleyball. The six basic skills are:

• Serve: Serving is done when the arm swings and sends the ball over to the opponent's side of the court. A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent. There are different serving styles in volleyball.
• Pass: Passing is the most important skill in volleyball. The pass is an attempt by a team to properly handle the opponent's serve, or any form of attack.
• Set: The set is used to receive a teammate's pass in order that the play may continue by passing the ball overhead to an attacker.
• Attack: The attack is also known as the spike. The object of attacking is to handle the ball so that it lands on the opponent's court and cannot be defended. 
• Block: Blocking is used to stop the ball from crossing the net as a result of an opponent's attack. Blocking is not allowed on serves. 
• Dig: Digging is the act of preventing the ball from touching one's court after an attack. The dig resembles a forearm pass and is used more for the balls that are hit near the defender. 

Water Pollution

    Water pollution is defined as the presence in groundwater of toxic chemicals and biological agents that exceed what is naturally found in the water and may pose a threat to human health and the environment. Additionally, water pollution may consist of chemicals introduced into the water bodies as a result of various human activities. Any amount of those chemicals pollutes the water, regardless of the harm they may pose to human health and the environment.

WATER POLLUTANTS

There are several classes of water pollutants.

•  The first are disease-causing agents such as  bacteria, viruses, protozoa and parasitic worms that enter sewage systems and untreated waste.
• A second category of water pollutants is oxygen-demanding wastes; wastes that can be decomposed by oxygen-requiring bacteria. When large populations of decomposing bacteria are converting these wastes it can deplete oxygen levels in the water. 
• A third class of water pollutants is water-soluble inorganic pollutants, such as acids, salts and toxic metals. Large quantities of these compounds will make water unfit to drink and will cause the death of aquatic life.
• Another class of water pollutants are nutrients; they are water-soluble nitrates and phosphates that cause excessive growth of algae and other water plants, which deplete the water's oxygen supply. 
• A very dangerous category is suspended sediment, because it causes depletion in the water's light absorption and the particles spread dangerous compounds such as pesticides through the water.  

Causes of Water Pollution

•   Industrial waste: Industries produce huge amount of waste which contains toxic chemicals and pollutants such as lead, mercury, sulphur, asbestos, nitrates and many other harmful chemicals. Industries do not have proper waste management system and drain the waste in the fresh water which goes into rivers, canals and later in to sea. These toxic chemicals are capable of changing the water’s colour, increase the amount of minerals and pose serious hazard to water organisms.

• Oil Spills: Oil spill pose a huge concern as large amount of oil enters into the sea and does not dissolve with water and therefore forms a thick layer on the water surface. These oil spills create problems for local marine life such as fish, birds and sea otters.

•  Burning of Fossils Fuels: Fossils fuels like coal and oil when burnt produce substantial amount of ash in the atmosphere. These particles fuse with water vapor resulting in acid rain which harms aquatic life. Carbon dioxide is released from the burning of the fossil fuels which leads to global warming. 

• Marine Dumping: Sewage let off from domestic households, factories, commercial buildings are untreated in water treatment plants yet are disposed into the sea. Sewage containing flush chemicals and pharmaceuticals causes greater problems.

• Mining activities: Mining is the process of crushing the rock and extracting coal and other minerals from underground. These elements when extracted in the raw form contains harmful chemicals and increase the amount of toxic elements when mixed with water which may result in health problems. Mining activities emit several metal waste and sulphides from the rocks and is harmful for the water.

 

Prevention

• Proper Disposal of Household Products: When it comes time to dispose unwanted paints, used oil, old cleaning solvents, furniture polish, pool chemicals, and other common household products, avoid discarding them down the sink, drains, or toilet. These items contain harmful substances, including sodium hypochlorite, petroleum distillates, ammonia, and formaldehyde. When they end up in nearby waters, everyone suffers.

• Preventing soil erosion: To prevent water from getting polluted, soil erosion should cease and soil conversation should be managed. The planting of more trees will stop soil erosion. Methods which can cultivate the soil and improve the health of the environment must be adapted and followed. 

• Promote the Clean Water Act: The Clean Water Act was created to set standards in controlling water pollution. Over the years, various laws have led to modifications in the act, but states are expected to follow government-set rules and regulations regarding the protection of the water supply used by local humans, wildlife, plants, and aquatic life.

•  Most industries directly flow their waste everywhere and reaches rivers through rain water. To prevent water pollution from industrial wastes, it is necessary that these wastes should be properly disposed. Some industries follow this rule, and they either destroy the remaining material, or re-use it safely.