Scientific Method In Action
The Strange Case of BeriBeri
In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was
beriberi. Symptoms of the disease included weakness and loss of appetite, victims often died of
heart failure. Scientists thought the disease might be caused by bacteria. They injected
chickens with bacteria from the blood of patients with beriberi. The injected chickens became
sick. However, so did a group of chickens that were not injected with bacteria.
One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the
chickens had eaten whole-grain rice, but during the experiment, the chickens were
fed polished rice. Dr. Eijkman researched this interesting case. he found that polished
rice lacked thiamine, a vitamin necessary for good health.
1. State the Problem
2. What was the hypothesis?
3. How was the hypothesis tested?
4. Should the hypothesis be supported or rejected based on the experiment?
5. What should be the new hypothesis?
How Penicillin Was Discovered
In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in culture
dishes. He noticed that a mold called Penicillium was also growing in some of the dishes. A
clear area existed around the mold because all the bacteria that had grown in this area had
died. In the culture dishes without the mold, no clear areas were present.
Fleming hypothesized that the mold must be producing a chemical that killed the bacteria. He
decided to isolate this substance and test it to see if it would kill bacteria. Fleming transferred
the mold to a nutrient broth solution. This solution contained all the materials the mold needed
to grow. After the mold grew, he removed it from the nutruient broth. Fleming then added the
nutrient broth in which the mold had grown to a culture of bacteria. He observed that the
6. Identify the problem.
7. What was Fleming's hypothesis?
8. How was the hypothesis tested?
9. Should the hypothesis be supported or rejected based on the experiment?
10. This experiment lead to the development of what major medical advancement?
Identify the Controls and Variables
Smithers thinks that a special juice will Identify the:
increase the productivity of workers. He
creates two groups of 50 workers each and 1. Control Group
assigns each group the same task (in this
case, they're supposed to staple a set of 2. Independent Variable
papers). Group A is given the special juice
to drink while they work. Group B is not given the special juice. 3. Dependent Variable
After an hour, Smithers counts how many stacks of papers each
group has made. Group A made 1,587 stacks, Group B made 4. What should Smithers' conclusion
2,113 stacks. be?
5. How could this experiment be
Homer notices that his shower is covered in 6. What was the initial observation?
a strange green slime. His friend Barney
tells him that coconut juice will get rid of Identify the-
the green slime. Homer decides to check 7. Control Group
this this out by spraying half of the shower
with coconut juice. He sprays the other half 8. Independent Variable
of the shower with water. After 3 days of
"treatment" there is no change in the 9. Dependent Variable
appearance of the green slime on either side of the shower.
10. What should Homer's conclusion