Exercise 13
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Chapter 13
Exercise 13
Part II
1. Radium:
Problem: Why were the rays emitted by pitchblende stronger than the rays emitted by pure
uranium?
I. Hypothesis: The intensified rays were triggered by impurities.
Implication: Mixing pure uranium with impurities would intensify the emission of rays.
II. Hypothesis: The intensified rays came directly from some impurity.
Tests: 1. The only other radioactive element known to exist was thorium, and the
pitchblende was found to contain no thorium.
2. Neptune:
Problem: Why did the astronomical tables predict accurate results for Jupiter and Saturn
but not for Uranus?
2. A second search was made using star charts. The eighth planet was
discovered.
3. Atmospheric Pressure:
Problem: If nature abhors a vacuum, why did pumps and siphons fail to work through heights
of 30 feet or more, why was a vacuum created in Berti’s glass vessel, and why did the water
level always descend to the same level in the pipe?
Hypothesis: The water is supported in Berti’s pipe (and in other vacuum devices) by the
pressure of the atmosphere.
Tests: 1. Viviani poured mercury into a tube closed at one end. He found that when
the tube was inverted the mercury was supported about 29 inches from the
level of the mercury in the dish.
4. Spontaneous Generation:
A. Re: Redi
Problem: How can life arise from nonliving matter?
B. Re: Pasteur
Problem: How can life arise from nonliving matter in view of the fact that the
occurrence of fermentation requires the introduction of living yeast?
I. Hypothesis: Life comes only from life.
Exercise 13
III. Hypothesis: Life forms that developed in sterile nutrient solutions were deposited in
the solutions by dust particles.
Implication: Sterile nutrient solutions in which no life forms developed after a
prolonged wait would exhibit microbial life forms when exposed to dust
particles.
Part VI