Science exam revision Flashcards
Need to know
State and define the law of conservation of energy:
The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed
Types of energy (names and knowing what they are)
Kinetic Energy: Energy of motion.
Potential Energy: Stored energy due to position.
Thermal Energy: Energy from heat.
Chemical Energy: Energy in chemical bonds.
Electrical Energy: Energy from moving electrons.
Nuclear Energy: Energy in atomic nuclei.
Radiant Energy: Energy from light and electromagnetic waves.
Mechanical Energy: Sum of kinetic and potential energy in objects.
Sound Energy: Energy from vibrating objects.
Elastic Energy: Stored energy in stretched or compressed objects.
Gravitational Energy: Energy due to an object’s height.
Magnetic Energy: Energy in magnetic fields.
Common energy conversions in appliances
Light bulb: Electrical energy to light and heat energy.
Toaster: Electrical energy to thermal energy.
Electric fan: Electrical energy to kinetic energy.
Difference between useful and waste energy
Useful energy is the energy that is successfully converted into the desired form, while waste energy is the energy that is lost to the surroundings, usually as heat.
Calculate energy efficiency percentages:
Energy Efficiency=
(Useful Energy Output Total Energy Input) ×100%
Give examples of how energy can be generated (EG: light or thermal energy):
Solar panels generate electrical energy from light energy.
Combustion generates thermal energy from chemical energy.
Be able to describe how energy is transformed (EG: in sports equipment):
In a basketball: Chemical energy (from the player’s muscles) to kinetic energy (movement of the ball) to potential energy (when the ball is at its highest point).
The difference between convection, conduction and radiation:
Convection: Transfer of heat through fluid (liquid or gas) movement.
Conduction: Transfer of heat through direct contact between materials.
Radiation: Transfer of heat through electromagnetic waves without the need for a medium.
Explain how heat is transferred from one object to another of differing materials
Heat transfers from the hotter object to the cooler one until thermal equilibrium is reached, through conduction, convection, or radiation depending on the context.
The difference between conductors and insulators:
Conductors: Materials that allow heat and electricity to flow easily (e.g., metals).
Insulators: Materials that resist the flow of heat and electricity (e.g., rubber, wood).
Identify sound waves as longitudinal or transverse:
Longitudinal waves: Particle displacement is parallel to the direction of wave propagation (e.g., sound waves).
Transverse waves: Particle displacement is perpendicular to the direction of wave propagation (e.g., light waves).
Understand how sound waves travel and in what mediums/temperatures they travel fastest/slowest:
These vibrations create sound waves which move through mediums such as air, water and wood
Sound travels fastest in solids, slower in liquids, and slowest in gases.
Sound travels faster at higher temperatures.
Be able to define wavelength
Wavelength: The distance between two consecutive points in phase on a wave (e.g., crest to crest).
define frequency
Frequency: The number of wave cycles that pass a point per unit time (measured in Hertz, Hz).
identify different frequencies in sound waves
Infrasonic waves are those that are too low-frequency (below 20 Hz) for humans to hear. Ultrasonic sounds waves are those that are too high-frequency (above 20,000 Hz) for humans to hear
Higher frequency corresponds to higher pitch in sound waves.
