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Zorluk: OrtaThermodynamics and Heat

On a clear, sunny afternoon at the beach, the dry sand becomes hot enough to burn bare feet, while the adjacent ocean water remains relatively cool despite receiving identical amounts of solar radiation. Which property accounts for this difference in temperature?

  1. A
    Water reflects virtually all incoming solar radiation away from its surface.
  2. Water has a significantly higher specific heat capacity than sand.Cevap
  3. C
    Sand undergoes rapid evaporative cooling when exposed to sunlight.
  4. D
    Sand converts absorbed radiant energy into potential energy rather than kinetic energy.

Cevap

Water has a significantly higher specific heat capacity than sand.
Specific heat capacity is the amount of heat energy needed to raise the temperature of a given mass of a substance by one degree Celsius. Water has one of the highest specific heat capacities of common natural substances (around 4.184 J/(g⋅∘C)4.184\text{ J}/(\text{g}\cdot^\circ\text{C})), whereas dry sand has a relatively low specific heat capacity (around 0.80 J/(g⋅∘C)0.80\text{ J}/(\text{g}\cdot^\circ\text{C})). As a result, receiving the same amount of solar radiation causes sand to experience a rapid and dramatic temperature increase, while water exhibits only a modest temperature change.

Adım Adım Çözüm

1
Analyze the thermal conditions described in the scenario
Both the sand and the water absorb equal radiant solar energy per unit area over the same duration, but the sand reaches a much higher temperature.
Establishing equal energy input isolates material-specific thermal properties as the cause of the temperature variance.
2
Apply the thermodynamic definition of specific heat capacity (Q=mcΔTQ = mc\Delta T)
Temperature change is inversely proportional to specific heat capacity (ΔT=Qmc\Delta T = \frac{Q}{mc}).
Specific heat capacity (cc) measures the amount of heat energy required to raise the temperature of one unit of mass by one degree Celsius.
3
Compare the specific heat capacities of water and sand
Water has a specific heat capacity of approximately 4.184 J/(g⋅∘C)4.184\text{ J}/(\text{g}\cdot^\circ\text{C}), whereas dry sand has a specific heat capacity of approximately 0.80 J/(g⋅∘C)0.80\text{ J}/(\text{g}\cdot^\circ\text{C}).
Because water requires roughly five times more energy per gram to raise its temperature by one degree, it warms up far more slowly than sand under the same sun exposure.

Anahtar Kavram

Specific Heat Capacity and Thermal Inertia
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Thermodynamics and Heat

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