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Which statement describes a scientific model? Tick one box - AQA - GCSE Physics - Question 9 - 2018 - Paper 1
Question 9
Which statement describes a scientific model? Tick one box. - an idea used to explain observations and data - a collection of personal thoughts - a guess or estima... show full transcript
Worked Solution & Example Answer:Which statement describes a scientific model? Tick one box - AQA - GCSE Physics - Question 9 - 2018 - Paper 1
Step 1
Step 2
Why do scientists sometimes have different models like the wave and particle models of light?
Answer
Scientists develop different models to provide explanations that may be appropriate in different contexts. For example, the wave model is useful for explaining phenomena like diffraction, while the particle model can explain photoelectric effect observations.
Step 3
Explain why scientists replace an old scientific model with a new model.
Answer
Scientists replace old models when they find new evidence that cannot be explained by existing theories. For instance, the replacement of the atomic model involving plum pudding with the Rutherford model illustrates this. New experimental evidence necessitated revising the understanding of atomic structure.
Step 4
Explain why refraction happens at the boundary between the deep water and shallower water.
Answer
Refraction occurs because the velocity of waves is different in deep and shallow water. As waves enter shallower water, their speed decreases, leading to a change in direction. The part of the wave front entering shallower water slows down, causing bending of the wave front at the boundary.
Step 5
Explain why the wave fronts in Figure 17 do not refract at the boundary.
Answer
In Figure 17, the wave fronts are traveling parallel to the boundary. Since all parts of the wave front enter the shallow water at the same time, they slow down uniformly, resulting in no change in direction, hence they do not refract.