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Scientists sometimes replace one scientific model with a different model - AQA - GCSE Physics - Question 10 - 2018 - Paper 1
Question 10
Scientists sometimes replace one scientific model with a different model. For example, in the early 20th Century the plum pudding model of the atom was replaced by ... show full transcript
Worked Solution & Example Answer:Scientists sometimes replace one scientific model with a different model - AQA - GCSE Physics - Question 10 - 2018 - Paper 1
Step 1
What evidence from the alpha particle scattering experiment led to the replacement?
Answer
The alpha particle scattering experiment conducted by Ernest Rutherford in 1909 revealed crucial insights. In this experiment, alpha particles were directed at a thin gold foil. Most of the particles passed straight through, suggesting that atoms are mostly empty space. However, a small number were deflected at large angles, indicating the presence of a concentrated mass within the atom.
Step 2
How did the findings regarding atomic structure challenge the plum pudding model?
Answer
According to the plum pudding model proposed by J.J. Thomson, atoms were envisioned as a positively charged sphere with negatively charged electrons embedded within it, akin to plums in a pudding. However, the experimental results indicated that if atoms were mostly empty space, then the plum pudding model could not accurately account for the concentrated mass (the nucleus) that was causing the deflections.
Step 3
What conclusion did Rutherford draw from his experiment that led to the nuclear model?
Answer
Rutherford concluded that atoms contain a small, dense, positively charged nucleus at the center, with electrons orbiting around it. This conclusion proposed a more refined atomic structure where the majority of the atom's mass is concentrated at the nucleus, significantly differing from the plum pudding model.