Read the following passage focusing your attention on the scientific procedures
ID: 1432785 • Letter: R
Question
Read the following passage focusing your attention on the scientific procedures and scientific abilities illustrated in it.
During an evening lecture in April 1820, while H. C. Oersted was preparing a demonstration for one of his advanced classes, he discovered something that surprised him. It is perhaps the only case known in the history of science when a major scientific discovery was made in front of a classroom of students. Precise details of the discovery are not available. All that we have are three accounts by Oersted himself and scattered remarks of students, none of which agrees at every point with the others. Oersted, for example, speaks in his account from 1821 as if he were deliberately testing the effect of an electric current on a magnetic needle, in his earlier account he wrote:
“(In) my lectures on electricity, galvanism, and magnetism in the spring of 1820, the auditors were already considerably advanced in science; so the preparatory reflections led me on to deeper investigations than those which are admissible in ordinary lectures. Thus my former conviction of the identity of electrical and magnetic forces developed with new clarity, and I resolved to test my opinion by experiment. I called attention to the variations of the magnetic needle during a thunderstorm, and at the same time I set forth the conjecture that an electric discharge could act on a magnetic needle placed outside the galvanic circuit. I then resolved to make the experiment. The effect was certainly unmistakable.”
However a student report asserts that the experiment concerned the heating of some platinum wire by means of an electric current, and that a compass needle happened by chance to be underneath the conducting wire. Professor Oersted was demonstrating the heating effects of the voltaic pile and as he was setting up his materials, he brought a compass close to a live electrical wire and the needle on the compass was deflected: it rapidly rotated to place itself perpendicular to the direction of the current. Oersted was surprised so he repeated the experiment several times. Each time the needle jumped.
The effect was only slight, because the current was small. Few months later, Oersted published a paper that was translated into the major languages without delay. His discovery of the magnetic effect of electrical currents was immediately recognized as an epoch-making advance.
Adapted from “Oersted and the Discovery of Electromagnetism” by Frederick Gregory.
Now reread the passage and answer the following questions:
1. The passage recounts an important advance in the understanding of magnetism. The same episode was reported differently by Prof. Oersted and one of his students. What type of experiment was this incident according to Oersted? What about according to the student? In each case how do you know?
2. What is the purpose of an observation experiment? What is the purpose of a testing experiment?
3. Describe the phenomenon investigated in the observation experiment described in the passage.
4. What are the predictions (implicit or explicit) described in the above text?
5. What type or types of experiments must include a prediction? Why?
6. What is the place of a hypothesis in an observation experiment? What about in a testing experiment? Give an example of each.
Explanation / Answer
1. Acccording to Oersted, this is a testing experiment. Refer to the sentence "I resolved to test my opinion by experiment" in Oersted's account.
According to the student, this is an observation experiment. Refer to the phrase " Professor Oersted was demonstrating the heating effects of the voltaic pile " in the student's account.
2. The purpose of an observation experiment is to demonstrate known scientific facts to the students.
The purpose of a testing experiment is to test a hypothesis, which is formed from many observations. sometimes these observations may be unrelated to the hypothesis.
3. An electric current generated by an Voltaic pile, is passed through a platinum wire. And the current heats up the wire.
4. An electric current when passed through a platinum wire, will heat the wire.
5. Testing experiments must include a predition. Since they are performed to test a hypothesis.
6. The role of a hypothesis is not central to an observation experiment. Because it involves simply demonstrating an already known fact. The above observation of electric current heating a wire is an example of observation experiment.
The role of a hypothesis is central to a testing experiment. Because it involves trying to establish the veracity of a hypothesis. The above description of electric current deflecting a compass needle is an example of testing experiment.
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