Energy and the Ocean 7 October 2014
Thermal Energy: the vibration and movement of particles due to excitation from an energy source.
Particles move more slowly when thermal energy is low…
Temperature: a measure of the average movement of all atoms, molecules or ions within a substance.
Heat Capacity: The amount of energy required to change a unit of temperature of a substance.
Water has a high heat capacity and consequently, the oceans are excellent heat sinks.
Without this ability to store large amounts of heat, Earth would experience large temperature fluctuations.
Example: Terra (has oceans) has a maximum surface temperature of about 136 degrees F. Terra has a minimum surface temperature of -128 degrees F.
Example: Luna has a maximum surface temperature of 253 degrees F (can we say “human torch”?). Luna has a minimum surface temperature of -253 degrees F (Frosty the snowman would be complaining…)
Energy is the capacity to do work.
Energy transformations: changes from one form o energy to another.
Objects feel hot because the particles in those objects are moving more quickly than the particles in your hand.
Objects feel cold because the particles in those objects are moving more slowly than the particles in your hand.
Energy naturally will flow from an object of high energy to an object of low energy until equilibrium is reached. This is a consequence of the 2nd Law of Thermodynamics which states that entropy within an isolated system increases.
Thermal equilibrium is reached when there is no longer a difference in temperature between the objects.
What is entropy. Entropy is a lack of order; chaos What is entropy? Entropy is a lack of order; chaos. Cooler objects are more ordered than warmer objects, so if entropy is to increase, the cooler object will become warmer.
Conduction Convection Radiation Thermal energy can be transferred in 3 different ways. Conduction Convection Radiation
Conduction requires the direct contact between materials for energy exchange.
Radiation: is the movement of energy through space in the form of an electromagnetic wave.
Law of Conservation of Energy: aka the 1st law of thermodynamics, states that energy cannot be created or destroyed. The total quantity of energy in an isolated system will always remain constant.
Remember that energy can still be transformed into different forms.
When energy changes forms, some of the energy is lost as heat When energy changes forms, some of the energy is lost as heat. Nothing is 100% energy efficient. This is why a car engine gets hot or why the wind turbine fan gets warm.
Sea Turtle example of energy transformations…
An isolated system is a system in which there is a zero exchange of matter and energy with the external environment. Such systems do not exist!
An open system exchanges both energy and matter with an external system. All living things are examples of open systems.