Physics helps us understand how rainbows appear and how galaxies form as well as develop nuclear technology or cars that can withstand collisions.
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Physics and Energy Production
Imagine for a moment that you were born 300 years ago. There would be no electric lights, no cars, no big factories, and no computers. During the industrial revolution, when physicists and engineers developed new technology that used burning fossil fuels like coal and oil to create energy, the world changed dramatically in a very short time. Now, society is totally dependent on a steady supply of cheap energy.
The centuries-old problems are solved, but now society faces another energy problem. Most of our energy is from fossil fuels, but the demand for energy is rapidly outpacing the supply. In other words, we are running out. On top of that, burning these fuels releases chemicals that are bad for the environment, climate, and world health. Scientists can help solve the energy problem by using their expertise to develop new technologies producing clean energy and using renewable resources. Instead of fossil fuels, these technologies use atomic nuclei, the earth's heat, wind, water, the sun, and biomass to produce energy. Let's look more carefully one such technology!
Nuclear energy is stored inside the nucleus of atoms. Physicists first discovered how this energy was stored and then later developed a way to release it by splitting apart atomic nuclei, a process called nuclear fission. Even a very small amount of radioactive matter can release a huge amount of energy. No carbon dioxide or toxic fumes are released by nuclear power plants, so compared to fossil fuel-burning power plants, they pollute much less and produce more energy. Nuclear power plants were first built in the 1950's, and currently they supply about 10% of today's energy.
A nuclear power plant releases only water vapor, which means no air pollution or contribution to climate change.
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However, nuclear fission also produces radioactive waste, so nuclear power plants aren't a source of totally clean energy. To improve on nuclear energy production, physicists are now working on production methods of fusing the nuclei of two atoms together, called nuclear fusion. This is how energy is produced by the sun, and maybe one day we can do it here on Earth, too!
To produce energy by nuclear fusion, atomic nuclei are smashed together. The collision causes a large amount of energy to be released.
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In addition to nuclear power, scientists are using physics to extract energy from the sun, earth, wind, and water. These technologies are improving every day. Maybe one day we will be able to produce enough energy for the whole world without having to burn fossil fuels and create more pollution!
Physics and Water Resources
Another major world issue is the increasing scarcity of clean water. In the developing world, about 80% of all illnesses are caused by drinking unclean water, and people often have to walk many miles carrying heavy jugs just to get drinking water. According to the World Health Organization, about 8000 people worldwide die every single day because of waterborne diseases. This is a tragedy, and one that physics can help overcome.
To meet the challenge of providing clean, safe water for all people, scientists and engineers are working hard to develop new technologies, such as a widely used device called the LifeStraw. It is a portable, personal water filter that removes over 99.99% of disease causing bacteria and other microorganisms. It uses no dangerous chemicals, either. Water simply passes through a series of very small holes that trap any microorganisms that might be present.
The LifeStraw is a personal water filtration device that can prevent waterborne illnesses.
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Physics is also helping develop new methods of large-scale water purification, including creating clean drinking water from seawater through a process called desalination. Desalination already provides about 1% of the world's drinking water, and it is expected to be a major source of clean water in the future in areas like Australia and the American southwest that have both a dry climate and access to salt water. Salt can removed from water using a process called vacuum distillation in which water is boiled to create pure water vapor. When it boils, the vapor can be collected while salt stays behind. This leaves clean water to drink!
Physics also helps to make this process more efficient. At low pressure, molecules in water will be farther apart from each other, which means the water will boil at a lower temperature than normal. This means the vacuum distillation can be performed at relatively low temperatures using the waste heat generated by electric power plants or other industrial plants, making the process cheaper. Even better, more people can have access to clean, desalinated water. Water management is one of the biggest challenges facing society today, and physics is an important tool to help us meet this challenge.
Desalination plants create clean drinking water in arid environments like the southwestern United States and Australia.
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Lesson Summary
Physics is the science that seeks to understand the fundamental nature of matter and energy. Scientists and engineers use the knowledge gained from physics to create new technologies to address important social issues in a field called applied physics. Currently, energy generation and water management are two critical social issues that physics is helping us to address. New ways to produce energy, including nuclear fusion, are being investigated, and water purification and storage systems are being developed to insure that all people have access to clean drinking water.
