Tutor profile: Tim T.
Subject: Environmental Science
Should we completely abandon fossil fuels?
Fossil fuels have many environmental costs associated with them. Extraction and mining alter ecosystems, can lead to pollution (oil spills, acid mien drainage), and are typically dangerous occupations for workers. The burning of fossil fuels releases various pollutants and greenhouse gases, most notably nitrogen and sulfur oxides, VOCs, carbon dioxide, and methane. Earth's warming climate over the past several hundred years matches increases in CO2 concentrations, which coincides with the industrial revolution. Despite these many negative factors, our current infrastructure in completely setup for fossil fuels. Fossil fuels, especially oil and gas, are incredibly easy to transport and provide tremendous amounts of energy per volume of fuel. Renewable energy is still a growing industry and not without environmental impacts. Wind turbines can alter the aesthetics of the landscape and pose a hazard to migrating birds. Photovoltaic cells in solar panels use rare Earth elements that must be mined. Hydroelectric power disrupts river ecosystems, and nuclear energy has safety concerns and questions as to how to deal with waste. The most realistic solution is to continue to develop a wide variety of ways to power our civilization. A mixture and renewable, fossil, and nuclear fuel has the potential to curb emissions and promote sustainable energy use. Utilizing many different energy sources spreads environmental impacts out, potentially minimizing harm.
Subject: Basic Chemistry
What is a small chemical change that could totally alter the world?
Hydrogen consists of three natural isotopes, all differing in the number of neutrons. By far, the most common isotope is protium, which has an abundance of 99.98% and contains one neutron. The other isotopes, deuterium and tritium, are very rare and contain 2 or 3 neutrons, respectively. Earth would be unfathomably different if protium was not the most common isotope of hydrogen. Normal water naturally becomes less dense when it freezes. This allows ponds, lakes, and sea-ice to freeze at the water surface and float, maintaining liquid water beneath the ice. Ice made from the heavier hydrogen isotopes would sink. Ice would form at the water surface, then sink to the bottom of the lake bed. This process would repeat, making it possible for the pond or lake to freeze completely solid. These conditions would make life extremely difficult in these environments.
This is a question that has been asked by many of my students lately... is water wet?
I love this type of question... open ended, and any answer can be valid so long as evidence can be provided. So here's my explanation! A single water molecule consists of an oxygen atom bonded to two hydrogen atoms. The hydrogen atoms bond on one side of the oxygen atom. These two hydrogen atoms create a slight positive charge at one end of the water molecule, and the other end has a slight negative charge. This charge difference makes water a polar molecule, Polar molecules are attracted to other polar molecules. Because of polarity, water demonstrates cohesion, meaning water molecules will bond to each other. Cohesion is what makes water form droplets and demonstrate surface tension. Have you ever filled a glass with water over the top, only to see a dome of water extend beyond the lip of the glass? That's surface tension! So water molecules can bond to themselves. That makes water have water on it. Therefore, water is wet!
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