Advantages and Disadvantages of Nuclear Energy

Advantages:
1. produces no greenhouse gases
2. steam is released into the atmosphere by nuclear plants
3. such a powerful source of energy, more than fossil fuels.
4. from a relatively small amount of nuclear fuel, a very large amount of energy is produced

Disadvantages:
1. the biggest problem with the nuclear energy is the waste it produces is highly radioactive
2. the waste is made by using up all the fuel in nuclear reactors
3. the waste remains radioactive for 10 000 years or more
4. very little place to store the waste




The story of Three Mile Island:

On March 28, 1979, a technical problem occurred in a water pump at Three Mile Island. The water was cooling the reactor. When the pump failed, the reactor began to overheat. Another technical failure occurred in a halve that was releasing excess steam. The operators of the plant didn't have enough information to figure out what the problem was, and they made a number of errors that made the problem worse.
During the tense next few days, engineers tried to cool the reactor and solve the other problems that were happening inside the plant. The government of Pennsylvania advised children and pregnant women, the most vulnerable to radioactivity , to leave the area. Radioactivity was released into the air, and almost half the reactor melted down. However, the reactor meltdown was contained and eventually cooled. Although no one died in the accident, it made people fearful of the nuclear industry.

Bibliography:nuclear energy by Jim Ollhoff

Fusion energy: The Hope For Mankind

Scientists have been trying to make fusion power for 50 years. While knowledge has constantly advanced, it's unclear if the technological hurdles will be overcome anytime soon. It takes a lot of energy to make a process hot enough for fusion. However, if it works, fusion will produce more energy than is required to make it. Scientist believed that fusion will have no waste products-no greenhouse gases or long-term radioactive waste.

They also believed that fusion power plants will be safer than fission power plants. With fusion, there is little chance of melting down or releasing radiation. while fusion reactors would still be radioactive , most scientist believed that the reactor elements would only be radioactive for 50 to 100 years. The radioactive elements from fission reactors, on the other hand, will stay radioactive for thousands of years.

How does nuclear power plant produce electricity

A nuclear power plant controls the chain reaction of the uranium to produce heat in the reactor. Water is pumped through the hot reactor. Water is pumped through the hot reactor. Water heats up and turns into steam turns turbines. Then, a generator converts the motion of the turbines into electricity.
Uranium is used for fuel in power plants. It is a non-renewable energy source, but it is fairly common. Much of te uranium used in North America is mined in the western states.
Uranium itself is radioactive. Radioactivity is a stream of particles or rays given off by certain kinds of matter. Radiation can cause serious illnesses or death. The uranium is kept in a sealed building called a containment building. Radiation does not get into the water or air unless there is an acident or disaster.

Nuclear Energy

Nuclear energy produces electricity through a process called fission. In 1956, the first commercial nuclear power plant opened in England. In the United States, as of 2008, there were 104nuclear reactors producing about 20 percent of the country's electricity needs.Nuclear energy doesn't produce greenhouse gases , and no pollution is released into the air. Compared to coal or other fossil fuels, the emissions from nuclear power plants are very clean. Some people say we should build more power plants to reduce greenhouse gases pollution. However, the waste from nuclear energy stays dangerously radioactive for thousands of years.
Other than fission, there is another kind of nuclear energy is fusion. This is the energy that powers the sun and stars. However, scientists cannot yet control the process on earth. If scientists could learn how to create and control fusion, it could become an energy source that is clean and would never run out.

Nuclear Fission

Everything is made up of tiny atoms. Atoms are made up of protons, neutrons and electrons. Some elements, like helium are small, composed of only one proton. Some are large. Uranium, the heaviest element in nature, has 92 protons.
Because uranium is so heavy, the atoms break apart easily. This is why uranium is used as a fuel in nuclear reactors. Fisson happens when a neutron crashes into a uranium atoms and spilt it. The neutrons from that atoms then crash into other atoms, and so on. When huge numbers of neutrons are crashing into atoms, it is called a chain reaction. A chain reaction produces heat.
At the centre of the nuclear power plant is reactor, where fission takes place. Inside the reactor is a supply of uranium, called the core. If the uranium reactor were left on its own, the chain reaction would get out of control. It would became so hot that that the reactor would melt, and then it would pass through the floor. Dangerous radiation would escape in the air. This would be a terrible disaster called the meltdown. To prevent this, scientist have used cooling rods or control rod, that are lowered into the nuclear reactor. This keep the reactor from getting too hot,and control the change reactions.

Introduction to Marine Biology

To me the author of this blog I feel that the subject Marine Life is one of the most exciting topic. When I grow up I would like to be a marine biologist. Do you know want marine biology is about? If not, listen up! Marine biology is about the scientific study of any organism in the ocean or water bodies. marine biology classifies species based on the environment.Marine biology differs from marine ecology as marine ecology is focused on how organisms interact with each other and environment and biology is the study of the animal itself.Marine life is a vast resource, providing food, medicine, and raw materials, in addition to helping to support recreation and tourism all over the world. At a fundamental level, marine life helps determine the very nature of our planet. Marine organisms contribute significantly to the oxygen cycle, and are involved in the regulation of the Earth's climate. Shorelines are in part shaped and protected by marine life, and some marine organisms even help create new land.Marine biology covers a great deal, from the microscopic, including most zooplankton and phytoplankton to the huge cetaceans (whales) which reach up to a reported 48 meters (125 feet) in length.

bibliography:http://en.wikipedia.org/wiki/Marine_biology

Sharks' greatest enemy

Despite being all powerful, sharks are still invulnerable.They do have several formidable enemies other than man. The unfortunate shark that consumes a porcupine fish will suffer dire consequences. This unique fish will inflate itself inside the shark’s jaws, preventing the flow of water through the shark’s gills. This defense mechanism will asphyxiate the larger creature. The great squid and salt-water crocodile are both fierce shark hunters. The killer whale has been seen to swallow a shark whole.

While dolphins and sharks have been known to coexist peacefully, a dolphin can efficiently dispose of a shark. One technique of the dolphin is to swim full-speed towards the abdomen of the shark, smacking into this tender area and causing the shark’s delicate intestines to hemorrhage. Dolphins also bump into the gills of the shark, which destroys the shark’s ability to breathe. In one case, there was an aquarium where a shark and several dolphins had been living together without difficulty for some time when the dolphins, for unknown reasons, threw the shark out 20 feet away onto the floor.

bibliography:http://www.sharkattacks.com/enemies.htm

Sharks' extraordinary keen of smell

Shark's most sense is smell, it is so powerful that sharks are able to sniff a tea spoon of blood in a Olympic swimming pool, sharks can smell blood from up to 100 meters or more away. Once the shark identifies the scent and decides to pursue, it starts swimming. The shark's natural swimming motion of moving its head back and forth provides further assistance in determining where the scent is coming from. With each movement, the snout picks up more water for the shark to analyze, and the shark is able to tell whether it's coming from the right or left nare. This helps them determine which way to swim. The shark's nose may work so well because it doesn't have to do anything else. Sharks use their noses just for smelling. Breathing is accomplished with a shark's gills, and the shark's sense of smell is not connected to its mouth in any way. Sharks often don't know how something is going to taste until they've taken a bite.

bibliography:
http://animals.howstuffworks.com/fish/shark-senses1.htm

Sharks' buoyancy

Most people think that sharks like fish, have gas-filled swim bladders. Instead, sharks rely greatly on a oil-filled liver, which contain squalene. Did you know that even though sharks' cartilage is about half as dense as bone and the liver constitutes up to 30% of their body mass, sharks still have to keep on swimming or they would sink. To prevent sinking, sharks employ dynamic lift to maintain depth. Some sharks such as the Sand Tiger sharks store air in their stomachs, using it as a form of swim bladder. Very smart indeed!!! However certain shark species, like the nurse shark, are capable of pumping water across their gills, allowing them to rest on the ocean bottom.

Sharks intelligences. Stupid or Smart?

Most people would think that shark are crazy, insane "killing machine" but in actual facts recent studies have indicated that many species possess powerful problem solving skills, social skills and curiosity. I guess you wouldn't believe this, sharks' brain- to body-mass ratios of sharks are similar to mammals and birds. One of the examples of the intelligence is that a group of up to seven great white sharks worked together to move a partially beached dead whale to deeper waters to feed. Sharks too, like dolphins can engage in playful activities. Porbeagle sharks have been seen repeatedly rolling in kelp and chasing an individual who trailed a piece of kelp behind it.

Introduction to Sharks

Sharks are a type of fish with a full cartilaginous skeleton and a highly skeleton and streamlined body. Did you know the earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs. Scientist has only found 440 species of sharks. Ranging from small-sized dwarf shark to the enormous whale shark, which can grow up to approximately 12 metres (39 ft 4 in) and which feeds only on plankton, squid and small fishes by filter feeding. Sharks are found in all seas and are common down to depths of 2,000 metres (6,562 ft). Most sharks lived in the ocean but some sharks like the bull shark can live in fresh water too. All sharks breathe through 5 to 7 gill slits and they do not have scales but a toothed-like skin which enable them to shark faster.