american science history

All of the changes, diversifications, and extinctions that happened over the course of life's history are the patterns of overall evolution. Evolution of life has been taking place for about 3.8 billion years of time. When we view macroevolution - the large-scale evolutionary histor..

The central ideas of evolution are that life has a history-it has changed over time-and that different species share common ancestor..

In spite of many evidences, studies and theories, we are still not aware of how the evolution actually occurs. If we go backwards at some point in the history of the earth it would have consisted of only the basic elements, the non-living materials like the air, water, sunlight etc. It i..

Although Rutherford's model was enormously successful at explaining the scattering of alpha particles, there was a problem when the experimental data were used to calculate the mass of the nucleus. From the results of the scattering experiments, it was possible to calculate the charge on the nucle..

Appliances used in our day to day life are based on the principles of electricity and magnetism. Electricity is one of the most important sources of energy. Lights, fans, motors, radios and television are some common appliances which work on electricity. Historically, it was frictional electri..

DNA is a double stranded molecule (double helix) with each strand being made up of many nucleotide units. Each nucleotide is made up of a nitrogenous base, a sugar molecule and a phosphoric acid molecule. Each DNA molecule has two such polynucleotide chains joined to each other by hydrogen bonds. ..

Structure of the earth system Earth's history Earth in the solar syste..

Structure of the earth system Earth's history Earth in the solar syste..

The history of the fax machine begins in 1843 in England with Alexander Bain. He devised an apparatus made up of two pens connected to two pendulums. He joined the two together with a wire, and was able to reproduce writing onto an electrically conductive surface. Some years later, in 18..

In a college campus, there are 9 French professors, 15 math professors, 12 science professors, 8 psychology professors, and 6 history professors. If a professor is selected at random, then find the probability that he is a French professor or a math professor. => 0.36 or 0.24 or..