Hypotheses, Scientific Theories, Laws and Models

Multiple-Choice Questions

1 A scientific hypothesis is:

(a) A tentative explanation that can be tested
(b) An established scientific law
(c) An unquestionable fact
(d) None of these

2 Which of the following is an essential feature of a scientific hypothesis?

(a) It must be universally accepted
(b) It should generate testable predictions
(c) It must be impossible to disprove
(d) None of these

3 A hypothesis that can be tested and potentially shown to be false is described as:

(a) Subjective
(b) Metaphysical
(c) Falsifiable
(d) None of these

4 Which statement best distinguishes a scientific theory from a hypothesis?

(a) A theory is always an unsupported guess
(b) A hypothesis is always more established than a theory
(c) The two terms have exactly the same scientific meaning
(d) None of these

5 A scientific theory is best defined as:

(a) A well-substantiated explanatory framework supported by extensive evidence
(b) A personal opinion
(c) A prediction without supporting evidence
(d) None of these

6 Which of the following is a well-established scientific theory?

(a) Theory of spontaneous generation
(b) Theory of evolution by natural selection
(c) Theory that Earth is flat
(d) None of these

7 The germ theory of disease explains that:

(a) All diseases are caused by poor nutrition
(b) Diseases are caused exclusively by heredity
(c) Many diseases are caused by microorganisms or other infectious agents
(d) None of these

8 The theory of plate tectonics explains:

(a) The movement of Earth’s lithospheric plates
(b) The circulation of blood
(c) The formation of chemical bonds
(d) None of these

9 A scientific law generally describes:

(a) A moral obligation
(b) A regular pattern or relationship in nature
(c) An unsupported prediction
(d) None of these

10 Newton’s law of universal gravitation describes:

(a) The chemical composition of stars
(b) The inheritance of genetic traits
(c) The gravitational attraction between masses
(d) None of these

11 Which statement about scientific laws and theories is correct?

(a) Laws describe patterns, while theories explain phenomena
(b) Theories always become laws after sufficient testing
(c) Laws are merely untested hypotheses
(d) None of these

12 A scientific theory does not become a law because:

(a) Theories are always less reliable
(b) Laws and theories serve different scientific purposes
(c) Laws are opinions and theories are facts
(d) None of these

13 Which of the following is an example of a scientific law?

(a) Cell theory
(b) Germ theory
(c) Newton’s first law of motion
(d) None of these

14 The law of conservation of mass states that, in a closed system during an ordinary chemical reaction:

(a) Total mass remains constant
(b) Mass is always converted entirely into heat
(c) The number of molecules must remain constant
(d) None of these

15 A scientific model is:

(a) A physical object used only for decoration
(b) A representation of a system, process or phenomenon
(c) A statement that cannot be revised
(d) None of these

16 Which of the following is an example of a physical model?

(a) A mathematical equation
(b) A computer simulation
(c) A three-dimensional model of the human heart
(d) None of these

17 A mathematical model represents a system primarily through:

(a) Equations and quantitative relationships
(b) Artistic descriptions only
(c) Personal opinions
(d) None of these

18 A computer model is particularly useful when:

(a) No data or assumptions are required
(b) A complex system can be simulated computationally
(c) A physical process cannot be represented mathematically
(d) None of these

19 The Bohr model of the atom was historically important because it:

(a) Described atoms as indivisible solid spheres
(b) Rejected the existence of electrons
(c) Introduced quantized electron orbits in its model
(d) None of these

20 The modern quantum mechanical model of the atom describes electrons mainly in terms of:

(a) Fixed planetary paths
(b) Probability distributions and orbitals
(c) Solid spherical shells
(d) None of these

21 Which of the following best describes an assumption in a scientific model?

(a) A condition accepted for the purpose of constructing or simplifying the model
(b) A result that has been experimentally proven in every situation
(c) An error that must never be disclosed
(d) None of these

22 Models are useful in science because they:

(a) Reproduce every detail of reality
(b) Eliminate the need for testing
(c) Simplify complex systems to aid understanding and prediction
(d) None of these

23 A model’s limitations arise partly because:

(a) All models are necessarily inaccurate
(b) Models simplify reality and may omit relevant details
(c) Scientific models cannot be tested
(d) None of these

24 Which of the following is an example of a conceptual model?

(a) A physical globe
(b) A numerical weather simulation
(c) A scale model of a bridge
(d) None of these

25 The heliocentric model of the solar system places:

(a) The Sun near the centre of the planetary system
(b) Earth at the centre of the universe
(c) The Moon at the centre of the solar system
(d) None of these

26 Which scientist is historically associated with the development of the heliocentric model in early modern astronomy?

(a) Isaac Newton
(b) Nicolaus Copernicus
(c) Louis Pasteur
(d) None of these

27 A prediction derived from a scientific theory is useful because it:

(a) Prevents further investigation
(b) Makes the theory automatically correct
(c) Allows the theory to be tested against observations
(d) None of these

28 If repeated experiments contradict a hypothesis, scientists should:

(a) Reconsider or reject the hypothesis in light of the evidence
(b) Ignore all contradictory results
(c) Change the data without disclosure
(d) None of these

29 Which statement about a scientific theory is most accurate?

(a) It is only an educated guess
(b) It can be revised if strong new evidence requires it
(c) It cannot make predictions
(d) None of these

30 A null hypothesis commonly states that:

(a) A strong relationship must exist
(b) The researcher’s prediction is certainly correct
(c) There is no effect, difference or association of the specified kind
(d) None of these

31 An alternative hypothesis generally proposes that:

(a) There is an effect, difference or association to be investigated
(b) The null hypothesis must always be true
(c) The data are irrelevant
(d) None of these

32 In statistical testing, a p-value is:

(a) The probability that the null hypothesis is true
(b) The probability, assuming the null hypothesis and model assumptions, of obtaining results at least as extreme as those observed
(c) The probability that the research is important
(d) None of these

33 A theory is strengthened when:

(a) Evidence is selected to support it while contrary findings are ignored
(b) It is protected from independent testing
(c) Its predictions repeatedly withstand rigorous tests
(d) None of these

34 Which of the following best describes a paradigm in science?

(a) A broad framework of concepts, assumptions and methods guiding research
(b) A single experimental measurement
(c) A universal instrument for all disciplines
(d) None of these

35 A paradigm shift refers to:

(a) A minor change in laboratory equipment
(b) A major transformation in the prevailing framework of a scientific field
(c) A change in the units used for measurement only
(d) None of these

36 The transition from the geocentric to the heliocentric model is an example of:

(a) A change in chemical composition
(b) A change in biological classification
(c) A major transformation in scientific understanding
(d) None of these

37 The theory of relativity is associated with:

(a) Albert Einstein
(b) Charles Darwin
(c) Gregor Mendel
(d) None of these

38 The theory of evolution explains:

(a) The origin of all chemical elements
(b) Changes in inherited characteristics of populations across generations
(c) The movement of tectonic plates
(d) None of these

39 The cell theory states, among other principles, that:

(a) All organisms consist of atoms only
(b) Cells arise spontaneously from non-living matter
(c) Living organisms are composed of one or more cells
(d) None of these

40 Which of the following is a key principle of the kinetic molecular theory of gases?

(a) Gas particles are in continuous random motion
(b) Gas particles are permanently stationary
(c) Gas particles have no kinetic energy
(d) None of these

41 A model that successfully explains existing observations but fails to predict new findings may require:

(a) No further evaluation
(b) Reassessment, refinement or replacement
(c) Automatic acceptance as a universal law
(d) None of these

42 Which statement about scientific models is correct?

(a) A model is always a literal copy of the real system
(b) Models are useful only in physics
(c) Different models may represent different aspects of the same phenomenon
(d) None of these

43 The standard model of particle physics describes:

(a) Fundamental particles and three of the four known fundamental interactions
(b) The movement of planets around the Sun
(c) The complete theory of gravity
(d) None of these

44 Which fundamental interaction is not incorporated into the Standard Model of particle physics as a quantum field theory?

(a) Electromagnetic interaction
(b) Gravitational interaction
(c) Strong nuclear interaction
(d) None of these

45 A scientific theory is considered robust when:

(a) It has never been examined
(b) It depends on one unverified observation
(c) It is supported by diverse evidence and successful tests
(d) None of these

46 Which statement best describes the relationship between a hypothesis and a model?

(a) A hypothesis may be tested using predictions generated from a model
(b) A model can never be based on a hypothesis
(c) A hypothesis and a model are always identical
(d) None of these

47 A model’s predictive accuracy can be evaluated by:

(a) Its visual appearance alone
(b) Comparing its predictions with independent observations or measurements
(c) Counting the number of pages in its description
(d) None of these

48 Which of the following is a scientific explanation rather than a mere description?

(a) The rock is grey
(b) The water is boiling
(c) Explaining boiling through energy transfer and molecular motion
(d) None of these

49 Scientific laws and theories are both:

(a) Products of scientific investigation supported by evidence
(b) Personal opinions without testing
(c) Statements that cannot be revised
(d) None of these

50 Which statement most accurately summarizes the relationship among hypotheses, theories, laws and models?

(a) Every hypothesis eventually becomes a law
(b) They serve distinct but related roles in scientific explanation, description and prediction
(c) A scientific model is always more reliable than a theory
(d) None of these

Answer Key

1 (a) A tentative explanation that can be tested
2 (b) It should generate testable predictions
3 (c) Falsifiable
4 (d) None of these
5 (a) A well-substantiated explanatory framework supported by extensive evidence
6 (b) Theory of evolution by natural selection
7 (c) Many diseases are caused by microorganisms or other infectious agents
8 (a) The movement of Earth’s lithospheric plates
9 (b) A regular pattern or relationship in nature
10 (c) The gravitational attraction between masses
11 (a) Laws describe patterns, while theories explain phenomena
12 (b) Laws and theories serve different scientific purposes
13 (c) Newton’s first law of motion
14 (a) Total mass remains constant
15 (b) A representation of a system, process or phenomenon
16 (c) A three-dimensional model of the human heart
17 (a) Equations and quantitative relationships
18 (b) A complex system can be simulated computationally
19 (c) Introduced quantized electron orbits in its model
20 (b) Probability distributions and orbitals
21 (a) A condition accepted for the purpose of constructing or simplifying the model
22 (c) Simplify complex systems to aid understanding and prediction
23 (b) Models simplify reality and may omit relevant details
24 (d) None of these
25 (a) The Sun near the centre of the planetary system
26 (b) Nicolaus Copernicus
27 (c) Allows the theory to be tested against observations
28 (a) Reconsider or reject the hypothesis in light of the evidence
29 (b) It can be revised if strong new evidence requires it
30 (c) There is no effect, difference or association of the specified kind
31 (a) There is an effect, difference or association to be investigated
32 (b) The probability, assuming the null hypothesis and model assumptions, of obtaining results at least as extreme as those observed
33 (c) Its predictions repeatedly withstand rigorous tests
34 (a) A broad framework of concepts, assumptions and methods guiding research
35 (b) A major transformation in the prevailing framework of a scientific field
36 (c) A major transformation in scientific understanding
37 (a) Albert Einstein
38 (b) Changes in inherited characteristics of populations across generations
39 (c) Living organisms are composed of one or more cells
40 (a) Gas particles are in continuous random motion
41 (b) Reassessment, refinement or replacement
42 (c) Different models may represent different aspects of the same phenomenon
43 (a) Fundamental particles and three of the four known fundamental interactions
44 (b) Gravitational interaction
45 (c) It is supported by diverse evidence and successful tests
46 (a) A hypothesis may be tested using predictions generated from a model
47 (b) Comparing its predictions with independent observations or measurements
48 (c) Explaining boiling through energy transfer and molecular motion
49 (a) Products of scientific investigation supported by evidence
50 (b) They serve distinct but related roles in scientific explanation, description and prediction