While walking on the beach on the summer day, the heat from the sand will warm your feet. This is an example of A convection C. conduction B. radiation D. none of these
The Correct Answer and Explanation is:
Correct Answer: C. Conduction
Explanation
When you walk on the beach on a summer day and feel the heat from the sand warming your feet, this is an example of conduction.
Conduction is the process of heat transfer through direct contact between materials. In this case, your feet are in direct contact with the sand. The sun heats the sand throughout the day. As the sand becomes hot, it transfers thermal energy directly to your skin upon contact. The molecules in the hot sand vibrate faster due to the heat and collide with the cooler molecules in your feet, transferring energy and causing your skin to feel warm or even hot.
Let’s briefly look at the other choices to understand why they are incorrect:
- A. Convection: This is the transfer of heat through fluids (liquids or gases) due to the movement of molecules. It happens when warmer parts of a fluid rise and cooler parts sink, creating a circulation pattern. An example is warm air rising above the sand or water boiling in a pot. However, convection is not responsible for heating your feet in this situation because no fluid is involved in the transfer of heat between the sand and your skin.
- B. Radiation: This is the transfer of energy through electromagnetic waves, such as sunlight warming the sand or your skin directly. While radiation from the sun initially heats the sand, it is not the direct method by which your feet become warm when touching the sand.
- D. None of these: This is incorrect because conduction is clearly the mechanism at work.
In summary, when your feet get warm from standing or walking on hot sand, it’s a direct contact heat transfer process—conduction—that’s responsible for the sensation of heat.
