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Cracks may appear in the surface of a road on a very hot and sunny day - Junior Cycle Science - Question e - 2015
Question e
Cracks may appear in the surface of a road on a very hot and sunny day. (i) Explain why this happens. (ii) How does heat travel from the Sun to the Earth?
Worked Solution & Example Answer:Cracks may appear in the surface of a road on a very hot and sunny day - Junior Cycle Science - Question e - 2015
Step 1
(i) Explain why this happens.
Answer
On a very hot and sunny day, the temperature of the road surface increases significantly. As the temperature rises, the solid materials that make up the road (such as asphalt and concrete) undergo thermal expansion. This means that the particles within the solid vibrate more and move farther apart as they gain energy. As a consequence, the road expands. If the expansion is constrained due to underlying structures or if there are gaps and weaknesses in the material, stress builds up. Once the stress exceeds the material's tensile strength, cracks can form, leading to visible fissures in the surface of the road.
Step 2
(ii) How does heat travel from the Sun to the Earth?
Answer
Heat from the Sun travels to the Earth primarily through the process of radiation. Unlike conduction or convection, which require a medium to transfer heat, radiation can occur in a vacuum. The Sun emits energy in the form of electromagnetic waves, including visible light and infrared radiation. These waves travel through the vacuum of space and reach the Earth's atmosphere, where they are absorbed and converted into heat, warming the planet.