testing hypotheses

testing hypothesis 1

How do you test a hypothesis? In this example, we will look into the scientific literature to find data in studies that were done using scientific method. To test Hypothesis 1 from the concept "Development of Hypotheses," we need to see if the amount of CO2 gas released by volcanoes over the past several decades has increased. There are two ways volcanoes could account for the increase in CO2 : There has been an increase in volcanic eruptions in that time. The CO2 content of volcanic gases has increased over time globally. To test the first hypothesis, we look at the scientific literature. We see that the number of volcanic eruptions is about constant. We also learn from the scientific literature that volcanic gas compositions have not changed over time. Different types of volcanoes have different gas compositions, but overall the gases are the same. Another journal article states that major volcanic eruptions for the past 30 years have caused short-term cooling, not warming! Hypothesis 1 is wrong! Volcanic activity is not able to account for the rise in atmospheric CO2 . Remember that science is falsifiable. We can discard Hypothesis 1.

testing hypothesis 2

Hypothesis 2 states that the increase in atmospheric CO2 is due to the increase in the amount of fossil fuels that are being burned. We look into the scientific literature and find this graph in the Figure 1.1. Global carbon dioxide emissions from fos- sil fuel consumption and cement produc- tion. The black line represents all emis- sion types combined, and colored lines show emissions from individual fossil fu- els. Fossil fuels have added an increasing amount of carbon dioxide to the atmosphere since the beginning of the Industrial Revolution in the mid 19th century. Hypothesis 2 is true! Click image to the left or use the URL below. URL:

textbook_image

instructional diagrams

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questions

to test a hypothesis, a scientist could

a) look to the scientific literature.

b) perform experiments.

c) make observations.

-->  d) all of the above.

why does a hypothesis have to be falsifiable?

a) it must be able to pass all its tests.

b) only if it is falsified can it be right.

-->  c) it must be possible to show that it is wrong.

d) all of the above

the hypothesis - the increase in carbon dioxide in the atmosphere is due to increased volcanic activity - is wrong because

a) volcanic gas compositions and eruption rates have not changed over time

b) there has been an increase in volcanic eruptions in recent decades.

c) the carbon dioxide in volcanic gases has increased over time.

-->  d) volcanic gas compositions have changed, but eruption rates have not changed over time

when a hypothesis is being tested the scientific method is not followed, the hypothesis must be

a) accepted

b) discarded immediately

c) turned into a theory

-->  d) tested again

one of the reasons for the increase in carbon dioxide in the atmosphere is due to the increase in the amount of fossil fuels used.

-->  a) true

b) false

a series of steps that help to investigate a scientific question is

a) a hypothesis

b) data

-->  c) the scientific method

d) a theory

data are facts that have been uncovered from the scientific literature, or by systematic observations or experiments.

-->  a) true

b) false

which of these can help scientists to test a hypothesis?

a) observations

b) analysis

c) conclusions

-->  d) all of the above

having multiple working hypotheses helps in investigating a question.

-->  a) true

b) false

which type of data has been used to identify the phenomenon of increasing carbon dioxide levels in the atmosphere?

a) experiments

-->  b) measurements

c) visual observations

d) none of these

diagram questions

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