Question

how did lord kelvin attempt to determine the age of the earth?
by analyzing fossils and comparing them to living organisms
by measuring how quickly rocks conducted heat and calculating cooling time
by observing volcanic eruptions and lava flows
by comparing the thickness of rock layers in different parts of the world

Explanation:

Lord Kelvin used the theory of thermal conduction. He assumed the Earth was a cooling body and calculated its age by measuring rock heat conductivity and determining the cooling time from an initially molten state. The first option is about fossil analysis (related to paleontology), the third about volcanic observations (not his method), and the fourth about rock layer thickness (not his approach). So the correct option is the one about heat conduction and cooling time calculation.

Answer:

B. By measuring how quickly rocks conducted heat and calculating cooling time