1. If an object is in the path of a "beam" of energy, say from the sun, depending upon the object's molecular structure and color it will take the energy in and convert it to internal molecular vibrations (internal energy).
2. Any object will emit energy at the expense of its internal energy.
In reality, both (1) and (2) are happening simultaneously, most of the time. Describe why temperatures rise during the day and cool at night.
3. In reality, solid objects, because of their molecular structure, take in a given amount of energy from the sun and convert it to internal energy much more efficiently than water. They also lose energy more efficiently. Of the solid objects, metals do this very efficiently.The Specific Heat Capacity is defined as the ratio of the energy (calories) required to be absorbed (radiated) by one gram of a given susbstance to produce a 1oC temperature rise (fall). In the SI system of units it is defined as the number of Joules required to change the temperature of 1 kg of a substance 1oC.
Specific Heat Capacity (cp) = Æq/ÆT
ÆT =( 1/cp) Æq
For example, a gram of pure metal like silver would warm up 10oC upon absorbing 1 calorie of energy, but a gram of water would warm up only 1oC upon absorbing the same 1 calorie of energy. Note: 1 calorie = 4.186 joules (both are units of heat (energy)
cp (per gram)
|cp (per kg) (MKS)
|Ice (0 °C)||0.50||2093|
|dry air (sea level)||0.24||1005|