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Health and Diseases
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Worksheet 1 Microbes and disease
Time to Think (p. 7)
1.
They asked: “Where did the microorganisms which spoilt the meat broth come
from?”
2.
The aim of Pasteur’s experiment was to show whether the bacteria that spoilt
the meat broth came from the air.
3.
The results showed that the meat broth in Flask B (mouth not sealed) turned
cloudy and gave off a bad smell. But the meat broth in Flask A (mouth sealed)
remained clear and no bacteria were found. It can be concluded that the
bacteria that spoilt the meat broth came from the air.
4.
Flask C is set up to show that air, but not the bacteria in the air, can go into the
flask through the long and curved neck.
Time to Think (p. 9)
5.
The germ theory of disease states that infectious diseases are caused by
microscopic organisms called germs.
6.
Using more powerful microscopes, scientists (such as Koch) can identify
accurately the germs that cause specific diseases.
7.
(a)
As germs may spread through the air, food, water or by body contact, we
can control the spread of infectious disease by isolating the patients and
germs. We should also raise public awareness to sanitation and body
hygiene, and use antiseptic methods in surgery.
(b)
We can use drugs such as antibiotics to treat infectious diseases.
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Health and Diseases
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Worksheet 2 The story of childbed fever
Time to Think (p. 14)
1.
Semmelweis suggested that the medical students carried the cause of childbed
fever on their hands from the dead bodies to the women in the first ward.
2.
The steps of the scientific method: Asking questions after making observations
 Suggesting a hypothesis  Testing the hypothesis, usually by doing
experiments.
3.
He asked the medical students to wash their hands in chlorinated water before
delivering a baby. This practice greatly reduced the number of deaths in the
first ward.
The result provided strong evidence for his hypothesis, but did not prove that it
was correct.
4.
Yes, it suggested that the dead body contained a substance that caused childbed
fever.
5.
Culture the germs that caused childbed fever from patients of childbed fever.
Check the dead bodies to see whether they also have the same kind of germs.
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Health and Diseases
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Worksheet 3 The control and eradication of smallpox
Time to Think (p. 21)
1.
He observed that a person would only be infected by smallpox or cowpox once
in a lifetime, and that milkmaids who had cowpox never developed smallpox.
He asked the question: “Why did the milkmaids who had cowpox never
developed smallpox?”
2.
The aim of Jenner’s first experiment was to have the boy James to develop
immunity against cowpox. By infecting James with a mild form of cowpox, he
would become immune to the disease.
According to Jenner’s hypothesis, a person who had cowpox would become
immune to smallpox as well.
3.
The aim of his second experiment was to test that James, after recovery from
cowpox, would be immune to smallpox. From the results of his experiment, it
can be concluded that James became immune to smallpox.
4.
People were concerned about the side effects of taking the cowpox vaccine,
such as developing cow-like features in the body.
5.
(Open-ended answer) Students should be reminded that the idea of cowpox
vaccine was new to people, with risky consequences and it was against the
Christian doctrine. Furthermore, due to the primitive techniques in preparing
the vaccine, many of the results of vaccination were controversial.
6.
Suggested answer: Jenner had got the consent from James’ parents, so he could
perform the experiments on James. They were willing to take the risk because
there was a high chance for James to catch smallpox which was highly fatal.
Jenner could test his ideas on animals (such as dogs and cats) first before
applying it to humans.
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