Model 5

Question 1

1. Scientific method involves:

Answer 1

• Formulation of the hypothesis
• Testing of the hypothesis
• Analysing data and drawing conclusion

Question 2

2. Testing a hypothesis is called:

Answer 2

Experiment

Question 3

3. Dr Barry Marshall and Dr Robin Warren won a Nobel Prize in Medicine for their identification of Helicobacter pylori. What illness is caused by this bacterium?

Answer 3

Chronic gastritis and peptic ulcers

Question 4

4. What did Jan van Helmont conclude that plants gain most of their mass from?

Answer 4

Water

Question 5

5. Microwave’ oven was invented by:

Answer 5

Percy Spencer

Question 6

6. An investigator doing laboratory experiments and gathering data comes under:

Answer 6

Primary data

Question 7

7. The variable that the researcher changes or manipulates is called:

Answer 7

Independent

Question 8

8. A detailed description of a scientific work prepared in a formal structure that can be clearly interpreted by academics or other scientists is called:

Answer 8

Scientific report

Question 9

9. How does a field experiment differ from a natural experiment?

Answer 9

In a field experiment, a variable is manipulated. In a natural experiment, the researcher makes use of the existing conditions

Question 10

10. If something is testable, it involves which of the following?

Answer 10

A scientific explanation that can be tested and potentially falsified

Question 11

11. Define prediction

Answer 11

A statement about what will be observed before it actually occurs.

Question 12

12. A literature review requires:

Answer 12

• Planning
  
  • Good and clear writing
  • A deep understanding of the research topic

Question 14

14. The evidence that that an instrument, a technique or process used to measure a concept does indeed measure the intended concept , is called:

Answer 14

(d) Validity

Question 15

16. Which of the following statements most likely involves using data in a way that is not valid?

Answer 15

(d) The English teacher does not assign students a grade less than “B”

Question 16

17. An experiment that uses precise measuring devices and gather data using an appropriate method can be said to be:

Answer 16

(d) Accurate

Question 17

18. The last step of the scientific method involves:

Answer 17

Drawing conclusions

Question 18

19. What is the ‘Doppler effect’?

Answer 18

The increase of wavelength when the source moves away from the detector, and the decrease when the source moves towards the detector

Question 19

20. Suppose Priestley repeated his experiment using many kinds of plants besides mint, and that when different plants were placed under the jar the candle remained lighted for different periods of time. What would be a logical conclusion from these experiments?

Answer 19

Different plants release different amounts of oxygen

Question 20

Describe the experiment that was conducted by Priestly

Answer 20

Mice in a jar was an experiment conducted by Priestley. Priestley found that when the flame in a sealed jar containing a mouse went out, the mouse would die. He determined that the air sustaining the flame was sustaining the mouse
He found that when a mouse was sealed in a jar with a plant and placed in sunlight, the mouse would survive. He concluded that the plant was “refreshing the air”.

• He used mercuric oxide to produce oxygen.

Question 21

Outline reasons why experiments such as Priestley’s would not be considered ethical in the modern society.

Answer 21

Mice in a jar.
Priestley’s experiment wouldn’t be considered ethical in modern society as it involves experimentation on animals. His experiment involved experimentation on mice though the process of the experiment mice died. Killing animals would not be considered ethical in modern society.

Mercury oxide
Priestley experimented involved gassing mice. This experiment wouldn’t be considered ethical in modern society as it animal cruelty to experimentation and inflicting harm on mice. Furthermore, though the condition Priestley breath in the substances himself this wouldn’t be consider ethical.

*Mercury is toxic to living organism.

Question 22

Describe TWO reasons why scientists such as Eratosthenes and Doppler took a long time to do their investigation and research.

Answer 22

• One of the reasons why it took such a long time for Eratosthenes and Doppler to complete their investigation and research is they both worked independently while conducting their investigation.
• Furthermore, when Eratosthenes and Doppler conducted there experiment, they didn’t have access to the technology we have today instead they relied on what they had at the time.
• This is evident in, Eratosthenes investigation, limitation present at the time was he could only conduct his experiment they didn’t have any way to accurately measure the distances between the two places, so he had to relies on estimation made my people who travelled between the two places. Furthermore, Eratosthenes used two stick to determine the circumference of the earth they today we have access to telescopes which can be sent out to spaces
• This can be also seen in the Doppler effect. At the time he used spectrograph and spectacle lines changes to monitor the stars to collect data. This is a long – time consuming and tedious process nowadays we can use telescopes to make observation about the movement of stars.
• Therefore, Eratosthenes and Doppler took a long period of time to conduct there investigation due to working individually the limited technology available.

Question 23

Mod 5 – Question 1
What type of scientific methodology did Marshall and Warren employ that resulted in a breakthrough when investigating the cause of peptic ulcers?

Answer 23

C. Primary investigation

Question 24

Mod 5 – Question 2
The graph shows the relationship between volume and pressure.

How are the variables related?

Answer 24

A. As pressure is increased, volume decreases at a decreasing rate.

Question 25

Mod 5 – Question 5
Which of the following comments made by consumers about two bath soaps, OLOSOL and FLUX, could only be checked by asking the consumers?

Answer 25

D. OLOSOL and FLUX both make showering a pleasure.

Question 26

Mod 5 – Question 6
Eratosthenes performed an investigation at Syene and Alexandria to estimate the circumference of Earth.
Which of the following could be an example of secondary data that Eratosthenes collected to complete his investigation?

Answer 26

A. The distance between Syene and Alexandria

Question 27

Mod 5 – Question 7
A student wanted to test the idea that the performance of students in Mathematics examinations would be worse if they did not eat breakfast.
Which of the following would be the best control group for this experiment?

Answer 27

A. A group that ate breakfast and attempted the same examination as the test group

Question 28

Mod 5 – Question 8
A student carried out an investigation to measure the impact of a specific fertiliser on plant growth. At the end of the investigation, the student measured the height of a plant three times with a 30 cm ruler. He recorded the measurements in the table.
Measurement Height of plant (cm)

1 22.2
2 22.3
3 22.4

Which statement is the best explanation for the variation in the data?
A. The ruler was not suitable for this level of accuracy.
B. The student used a different ruler for each measurement.
C. The plant was growing while the student was measuring it.
D. The plant expanded and shrunk due to temperature changes at the time of measurement.

Answer 28

A. The ruler was not suitable for this level of accuracy.

Question 29

Mod 5 – Question 9
A student wanted to investigate the water content of a variety of foods. The student weighed out exactly 5 g of a variety of food samples including apple, raw beef, celery and tomato. The foods were then placed in an incubating oven for 4 days, removed and then reweighed.
What would be the dependent variable in this investigation?
A. The types of food samples used
B. The temperature of the incubating oven
C. The amount of mass lost after 4 days in the incubating oven
D. The amount of mass of each sample prior to being placed in the incubating oven

Answer 29

C. The amount of mass lost after 4 days in the incubating oven

Question 30

Mod 5 – Question 10
A university conducted research on high blood pressure. A researcher claims that applications of this research have led to a halving of the number of strokes and to a reduced number of heart attacks.
What does this information suggest?
A. The more money we spend on research the more people we can save.
B. It is more important to spend money on research than on treating people with diseases.
C. If this research on high blood pressure were to cease, then people will have shorter lives.
D. Applying research findings on high blood pressure could reduce the incidence of strokes and heart attacks.

Answer 30

D. Applying research findings on high blood pressure could reduce the incidence of strokes and heart attacks.

Question 31

Mod 5 – Question 11
A student plans to conduct an investigation to determine the effects of a soil pollutant on the growth of tomato plants. She designs a primary investigation and summarises her plan in the table below.
Plant Water (mL/day) Sunlight (hours/day) Pollutant (g)

1 150 12 0
2 250 12 1
3 250 12 10
4 450 12 100

Which of the following makes this investigation invalid?
A. The experiment uses one type of plant.
B. The experiment does not have a control.
C. The amount of water is different for each plant.
D. The amount of pollutant is different for each plant.

Answer 31

C. The amount of water is different for each plant.

Question 32

Mod 5 – Question 12

A student performed an investigation that had an unexpected result. Before telling anyone about this result, the student decided to perform the investigation again.
Which of the following best explains why it was appropriate for the student to do this?
A. To average the results
B. To get different results
C. To use up extra equipment and chemicals
D. To make sure that the investigation could be replicated

Answer 32

D. To make sure that the investigation could be replicated

Question 33

Mod 5 – Question 14
An investigation was carried out to measure how quickly substances dissolve at different temperatures.
The thermometer used for the investigation was faulty because a small part of the liquid column had become detached and stuck near the 70°C mark. In all other respects the thermometer was responding normally to changes in temperature. The diagram shows the thermometer when the actual room temperature was 18°C.

Which statement is correct about the investigation carried out using this thermometer?
A. The investigation is valid because the thermometer is responding normally to temperature changes.
B. The investigation is reliable because consistent results can be obtained when the experiment is repeated.
C. The investigation is invalid because correct temperature readings can only be deduced if the temperature is 73°C.
D. The investigation is unreliable unless the person recording the measurements adds 3°C to each of the temperatures observed.

Answer 33

B. The investigation is reliable because consistent results can be obtained when the experiment is repeated.

Question 34

Mod 5 – Question 16 (4 marks)
Identify an example of a known scientist who deviated from the traditional model of 4 scientific methodology and explain how the scientist deviated from the traditional model.

Answer 34

In the early 1980s Warren found that 100 patients with gastritis all had a huge number of curved bacteria present in their intestines. These bacteria were not present in healthy people. Marshall was able to culture and identify these bacteria. They published their results and many microbiologists were convinced that there was a strong link between the presence of these bacteria and gastritis, but pharmaceutical companies and doctors believed that the gastritis made sufferers susceptible to infection.
Warren and Marshall wanted to show that it was H. pylori that caused gastritis, not that it was a consequence of gastritis. Animals did not develop gastritis when infected with H. pylori. Usually a research plan would be submitted to an ethics committee, funding would need to be acquired, stringent rules would be applied, many subjects would need to be found and screened and different testing protocols would be used. In a change from traditional scientific methodology, Marshall, who was perfectly healthy, deliberately infected himself by drinking a solution containing H. pylori. Marshall developed the symptoms of gastritis, then self-medicated with antibiotics targeting H. pylori and was cured. This unusual act proved that H. pylori caused gastritis and treating gastritis with antibiotics targeting H. pylori will cure gastritis.