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GCSE level questions on light

Q3. Light is usually described as a wave. Light can also be described as a stream of particles. These are two different scientific models of light.

(a) Which of the statements in the table below best describes a scientific model? Tick one box.

Statement Tick here
A small scale version of a real object.  
A way of guessing what will happen.  
An idea used to explain observations and data.

 

[1 mark]

(b) Explain why scientists sometimes have different models to describe a phenomenon - like the wave and particle models of light.

One particular model may not be able to explain all observations, so different models may be appropriate in different situations.

[1 mark]

(c) Sometimes an old scientific model is replaced by a new model. Explain why scientists replace an old scientific model with a new model. Include an example from Physics in your answer.

If new experimental evidence or data cannot be explained using an existing model or predictions made using old model are shown to be incorrect a new model is needed. The new model is devised to explain the new evidence. Then predictions made with new model are investigated and if they are shown to be correct the new model is adopted. (3 max)

A suitable physics example:

the nuclear model of the atom replacing the plum pudding model

the big bang theory replacing other theories for the creation of the universe

tectonic plates replacing static land masses

heliocentric model of solar system replacing geocentric model

 

[4 marks]

(Total 6 marks)