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The tropical rainforest is natural recycle, provider and protector for our planet.
The tropical rainforest supports the ecosystem in the world.
The tropical rainforest provides us with oxygen we breathe.
The tropical rainforest is the richest biological incubator on the Earth. It supports millions of plant, animal and insect species – a virtual library of chemical invention. Maybe the new drugs are still awaiting discovery – drugs for AIDS, cancer, diabetes and arthritis. Many secrets and untold treasures await discovery with the medicinal plants used by shamans, healers and indigenous people of the Rainforest Tribes. So alluring are the mysteries of indigenous medical knowledge that over one hundred pharmaceutical companies and even the US government are currently funding projects studying indigenous plant knowledge and the specific plants used by native shamans and healers.
The problem and the solution to rainforest destruction are both economic. The destruction is caused by slash-and-burn agriculture, cattle ranching, building of dams and highways, and mining. So, if landowners, governments and people living in the rainforest were given a viable economic reason not to destroy the rainforest, it could and would be saved. Thankfully, this viable economic alternative exists.
Many organizations have demonstrated that if the medicinal plants, fruits, nuts, oils and other resources like rubber, chocolate and chicly were harvested sustainably, rainforest land has much more economic value than if timber were harvested or if it were burned down for cattle or farming operations.
Nuclear energy
Nuclear energy is often called the energy of the future because of a great amount of advantages, but millions of people are afraid of radiation. On the one hand using nuclear power gives us more variety in fuel sources. On the other hand is the remembrance about Chernobyl tragedy. Different countries use nuclear energy even now, but people from all over the world suppose that using nuclear energy is a big mistake.
There are some advantages of using nuclear:
Nuclear is the cleanest and least damaging to our environment. Since the energy released from splitting the uranium atom is so much greater than the energy released from combustion, the amount of land, materials, and fuel used, and wastes produced, are very much smaller.
Using nuclear power gives us more variety in fuel sources. It helps us avoid being dependent on other countries for only one or two types of fuels.
Nuclear isn’t limited by location and natural conditions (for example, the need for regular winds or sunshine).
Nuclear generation of electricity provides savings over coal generation because of lower fuel and transportation costs for nuclear.
Nuclear energy is the cheapest kind of energy.
All mentioned above are «pluses» of nuclear energy. And now let’s talk about minuses, about radiation.
Radiation
Radiation is a natural energy traveling in the form of waves or particles. Some everyday examples are: the microwaves we use to cook food, radio waves for radio and television, radar, X-rays used in medicine and dentistry, and sunlight. We also receive radiation as a result of the natural process of radioactivity. Materials that are radioactive are made up of atoms that contain excess energy. These radioactive materials give off their excess energy as radiation.
The three kinds of nuclear radiation that come from the radioactive materials are alpha, beta, and gamma radiation. All three types are present in nature. The natural radiation from soil, water, and cosmic radiation (the Sun) is called "background radiation."
Alpha particles are the nuclei (centers) of helium atoms. They can be blocked by a sheet of paper. Beta particles are high-speed electrons. They can be blocked by a thin sheet of aluminum. Gamma radiation, like the medical X-ray, consists of photons (electro-magnetic radiation), except that gamma radiation comes from the atomic nucleus. X-rays are lower in energy and come from the electrons around the nucleus. Gamma rays can be blocked by several inches of lead, several feet of concrete, or a large amount of water (for example, the 45-foot deep pools of water in which spent fuel is stored).
Реферат опубликован: 20/12/2006