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Some chemical reactions happen spontaneously, like metal rusting. Other reactions are non-spontaneous and need to absorb energy in order to occur. Using the Second Law of Thermodynamics, the principle of entropy, and the calculation of Gibbs free energy, scientists can predict which reactions will occur and vary the conditions to make more of the desired products. In equilibrium reactions, both products and reactants are always present. Equilibrium reactions in the human body are essential for life and can be exploited in chemical manufacturing as well. Part of the series Chemistry: Challenges And Solutions.
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air.
(Source: Library Lyna)
At Virginia Polytechnic Institute and State University, Christopher Williams heads the effort to further advance 3-D printing with copper, a widely used conductor in electronics. Williams is using a process called binder jetting in which an inkjet printer selectively jets glue into a bed of copper powder, layer-by-layer. The printed copper product is then taken to a furnace to fuse the particles together. With support from the National Science Foundation, Williams is addressing a major challenge in the 3-D copper printing process, which is to eliminate the porosity that develops in the part during the process. Part of the National Science Foundation Series “Science Nation.”
Conservation scientist Glen Gates at the Walters Art Museum in Baltimore is working on new ways to protect museum-quality silver from the ravages of time. Fine silverware and silver pieces on display at museums are exposed to air and tarnish. Every time someone polishes the silver, even under the careful supervision of conservation experts, a little bit of the silver wears away. Gates and colleague, Physics professor Ray Phaneuf at the University of Maryland, are working on a non-destructive method to preserve silver artifacts. With support from the National Science Foundation, they’re developing a nanometer-thick transparent coating that seals the silver. This coating keeps silver from tarnishing and eliminates the need to polish it.
In Miki, Japan, a six-story wooden model condominium was shaken by the equivalent of a 7.5 magnitude earthquake. The test was said to be the largest simulated earthquake ever attempted with a wooden structure. The full-scale building sat on a metal shake table that rocked it violently back and forth. The table, designed to hold up to 2.5 million pounds, reproduced forces based on those recorded during the 1994 earthquake in Northridge, California. But, it was scaled up by 180 percent to simulate an earthquake so violent it would only occur an average of once every 2,500 years. Part of the "Science Nation" series.
Scandium is a chemical element with the symbol Sc and atomic number 21. A silvery-white metallic d-block element, it has historically been classified as a rare-earth element.
Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black non-metallic solid at standard conditions
Monitoring water quality is vital to make sure dangerous bacteria doesn't creep into drinking water or overcome sewage treatment plants. With support from the National Science Foundation, engineers at the Monterey Bay Aquarium Research Institute have developed the Environment Sample Processor (ESP), a "DNA lab in a can." The size of a trash can, it can be placed in the open ocean or at water treatment facilities to identify potentially harmful bacteria, algae, larvae, and other microscopic organisms in the surrounding waters. It can monitor and send results back to the lab in real time to monitor water quality. Now, the engineers are modifying the ESP so it can go mobile, working from an autonomous underwater vehicle (AUV).
Microorganisms affect everyone. Some are helpful, while others are harmful. Explores pathogenic microorganisms that can cause diseases like sore throats, influenza, tuberculosis, and HIV; decomposer microorganisms that decay rotting plant and animal matter, returning important nutrients back into the soil; and microorganisms that are also being used in the fuel industry to develop new nonpetroleum based products. Overviews food spoilage microorganisms such as mold that can ruin stored food. Explains other bacteria and yeasts are vital to the production of food and drinks like yogurt and bread, along with beer and wine. Examines where they come from and some examples of positive uses relating to many foods we eat.
Mining traditionally has destroyed vegetation and topsoil as it takes minerals from the ground. New techniques and increased environmental awareness has recently led to new land reclamation experiments. Adding earthworms and bacteria to restore the land is one such venture. Highlights bioremediation--using living organisms-- to clean up heavy metals left as mining residue.
The image of a rat sniffing around for food with its little whiskers moving back and forth to help satisfy its appetite is enough to make most people lose theirs. But those whiskers play a valuable role in helping rats determine what is in the environment around them. With support from the National Science Foundation, Mitra Hartmann and colleagues at Northwestern University in Chicago are constructing whiskered robots that can detect and then project three-dimensional virtual images of objects on to a computer screen. Scientists here don't think it's so far-fetched that one day robotic rovers, much like the ones on Mars now, might contain a set of whiskers to help them navigate the terrain around them.
Teachers often say to students, “Put your thinking caps on,” and one day, students might just do that for real. Vanderbilt University psychologist Geoffrey Woodman says that’s because scientists are being equipped with more and more tools they can use to better understand the brain, and now, they can even eavesdrop on individual neurons. Initial support from the National Science Foundation (NSF) allowed Woodman and his team at the Vanderbilt University Visual Cognitive Neuroscience Laboratory to study memory and perception. Then, the researchers tested their theory that electrical stimulation of the medial frontal cortex can boost learning and improve decision-making. Part of the National Science Foundation Series “Science Nation.”
Mercury is a chemical element with the symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum. It is the only metallic element that is liquid at standard conditions for temperature and pressure.
Due to the development of computers and the growing number of programmers who develop new and improved software, there has been a wave of illegal software use, known as piracy. Companies are making advances in technology and increasing the number of computer programmers in an effort to reduce piracy. This is the Free Software model.
Figure 2.11 (OpenStax, Biology 2e) caption: In the formation of an ionic compound, metals lose electrons and nonmetals gain electrons to achieve an octet.
As shown on the History Channel. Gold dates from the time of the supernova explosion that gave birth to the building blocks of our solar system. When it was created, the Earth included a tiny percentage of gold atoms, and over the aeons geologic processes have concentrated it into various nooks and crannies around the globe. The best of it is in the ancient Precambrian rocks in South Africa, where the deepest mines in the world extract it. In other regions of the world, gold can be gathered from younger sedimentary rocks that have been eroded off older Precambrian rocks. The American gold rush was this type of deposit. Now in Nevada, sedimentary rocks are leached on a truly vast scale to extract the gold.
Showing collections 1 to 3 of 3
3D models and images of the entire periodic table of elements
A collection containing 118 resources, curated by Library Lyna
A collection of Chemistry related resources
A collection containing 67 resources, curated by Benetech
A collection of simulations from PhET.
A collection containing 15 resources, curated by Charles LaPierre