1.4 Kinetic Energy Curves
Consider a beaker of water sitting on a counter. The individual water molecules in the beaker are in constant motion. But - and this is the important point - the water molecules are not all moving at the same speed because they do not all have the same amount of kinetic energy. Some water molecules are sluggish and move slowly (they have a low kinetic energy). Some are very energetic (they have a high kinetic energy) and moving very fast. Most, however, are moving at some intermediate speed (or intermediate kinetic energy).
How could we best graph this variation in kinetic energy of particles? What would a graph of this look like?
Kinetic Energy Curve |
You may recognize the general shape as a basic bell curve (also called a normal curve.) As it applies to the kinetic energy distribution of a sample of matter, it is called a Boltzmann distribution, but we'll refer to it as a Kinetic Energy Curve. Learn this graph well - we'll see it again. |
Something to think about . . .
Which has more heat energy - an iceberg or a cup of boiling water?
Answer - the iceberg. Why? Because the much larger iceberg has many more molecules than does the cup of boiling water. Heat is the total kinetic energy - and more particles will have more total energy.