Specific heat is typically quoted in units of J/g/K or J/g/degreeC (Joules per gram per Kelvin or Joules per gram per degree Celcius). For example, if a substance has a heat capacity of 2 J/g/degreeC that means it takes 2 Joules of energy to raise the temperature of 1 gram of the substance by 1 degree Celcius. Note that when we are talking about temperature changes rather than absolute temperatures, a Kelvin is the same as a degree Celcius.
Why would you want to know the specific heat of a fluid? Well, suppose you want to Build your own flat panel solar thermal collector and you'd like to find or create a fluid that can store lots of energy for a small change in temperature. You might want to experiment with different fluid compositions to see what has the highest specific heat.
Step 1: Equipment
- Digital postal scale
- Plastic cup that will hold at least 250ml
- Variable power supply]
- Digital thermometer with probe
- 7.5 ohm, 5W resistor] (or something close)
- Short length of wire
- Clock showing time in seconds (not shown)
- 250 ml of cold water (tap water will do, distilled is better) (not shown)