Serena is a research student who has conducted an experiment on the discoloration of marble. Read about Serena’s experiment. The
n identify two flaws in her experiment’s design. Serena sees an article about the Taj Mahal, a medieval marble monument in India. She reads that the white monument is beginning to turn a dull yellow-brown. Serena admires the Taj Mahal and is eager to learn what might be causing the yellowing. She formulates a hypothesis that the yellow-brown tinge may be caused by air pollution from black carbon, brown carbon, or methane, combined with wind erosion.
To test her hypothesis, she decides to study the effects of these air pollutants and wind on white marble. She finds three identical pieces of white marble and exposes one of them to air containing black carbon, one to air with brown carbon, and one to air with methane. She also places a fan on two of the samples, varying the speed of the air stream in regular intervals. After a few days, the marble samples begin changing color, becoming grayish. Serena learns that air pollution caused the discoloration. However, she is not sure how it became gray instead of yellow and what exactly caused the discoloration.
She used identical pieces of marble for her samples. She introduced at least one confounding variable. She tried to test multiple hypotheses at a time. She attributed the marble discoloration to wind erosion. She used a mechanically-generated air stream rather than natural
<span>- She introduced at least one confounding variable.</span>
<span>- She tried to test multiple hypotheses at a time</span>
In the above mentioned experiment she had to have four samples to prove
four hypotheses, each one separately and not to mix two hypotheses in an alone
sample, that what it brings as consequence is the confusion.
The properties of magnets are used to make electricity. Moving magnetic fields pull and push electrons. ... Moving a magnet around a coil of wire, or moving a coil of wire around a magnet, pushes the electrons in the wire and creates an electrical current.
Alessandro Volta composed a letter to his amigo, Sir Joseph Banks at the Royal Society of London, in March 1800. In it, Volta drew an image of his voltaic heap, an exacting heap of 24 copper and zinc plates, in addition to cardboard circles absorbed salt. Volta at that point associated copper wires to both the top and base to utilize it as power source.
The voltaic heap and wires would at that point, in principle, charge something helpful, similar to a light or a little engine, however since neither existed in 1800, Volta put the two wires on the tip of his tongue. His tongue, wet with salivation, was a decent conductor and finished the circuit. Volta gave himself a decent stun, accordingly demonstrating he had made another sort of battery, or electrochemical vitality source.
While researchers presently don't prescribe putting live wires on your tongue, Volta was respected for his commitments to science and we named the volt (V), or the unit of measure for electric potential, in his respect.
