Energy Matters - Physics Flashcards
What is meant by the term energy?
Energy is the ability to do work or cause a change. Energy can not be seen but it is everywhere in both living and non-living things
What is the unit for energy?
Joules (J)
Types of energy and examples of each:
Chemical potential energy - Batteries
Elasic potential energy - Rubber band
Gravitational potential energy - Something up high
Kinetic energy - Ball rolling
What is the difference between potential & kinetic energy?
Potential energy is the stored energy an object has because of its position or condition, like a stretched rubber band. Kinetic energy is the energy of motion, like a moving car.
What is meant by the term Work?
Calculating the amount of energy that is used in carrying out the task
Law of conservation of energy
Energy can not be created or destroyed
What is the difference between an energy transfer and an energy transformation?
Energy transfer: when energy moves from one object to another like heat moving from a hot cup of tea to the surrounding air.
Energy transformation: when energy changes from one form to another, like when sunlight is converted into electrical energy in solar panels
What is thermodynamics? What is a closed thermodynamic system?
Thermodynamics is the study of how heat (thermal energy) can be transferred between objects or transformed into other forms of energy.
Thermodynamic energy is the total energy of all moving or vibrating particles in an object.
A closed system can exchange energy (as heat or work) but not matter, with its surroundings.
How does thermal equilibrium occur?
When 2 objects are at different temperatures, there is a temperature gradient. The thermal energy of a hot object will be transferred down the temperature gradient to the cooler object When the thermal energy of an object is the same as its surroundings, thermal equilibrium has been achieved.
(temperature gradient describes in which direction and at what rate the temperature changes)
How does conduction work as an example of heat transfer?
Occurs when two objects at different temperatures are in contact with each other.
Heat flows from the hotter object until they are both at the same temperature.
How does convection work as an example of heat transfer
Is the transfer of heat by the movement of a fluid (liquid or gas) between areas of different temperatures.
Warm air is less dense than cold air, and so convection currents can form in the presence of a temperature gradient.
