2B3 Energy Flashcards
Differentiate between the various energy types and their applications, and explore energy transformation from one form to another.
Define:
energy
The ability to do work.
Energy can be categorised into potential and kinetic energy.
Work involves moving an object by force.
List four types of potential energy.
- Chemical energy
- Elastic energy
- Gravitational energy
- Nuclear energy
Potential energy is the energy stored in an object due to its position or arrangement.
Name five types of kinetic energy.
- Electrical Energy
- Radiant Energy
- Thermal Energy
- Sound Energy
- Mechanical Energy
Kinetic energy is energy in motion.
List three examples of kinetic energy.
- A ball rolling down a hill.
- Dogs running.
- Cars driving.
The kinetic energy of each of these examples can be calculated using the equation, KE = 1/2 mv².
Where m is the mass and v is the velocity.
The KE equation shows how velocity plays a greater role due to its squared value.
List three examples of potential energy.
- A ball at the top of a swing.
- A car stopped at the top of a hill.
- Books on a shelf.
The potential energy (PE) of each of these examples can be calculated using the equation, PE = mgh.
Where m is the mass, g is gravity, and h is the height.
PE equation demonstrates how position influences energy storage.
Fill in the blank:
Kinetic energy can be transferred, while potential energy _______.
cannot
Kinetic energy is transferred when a moving object applies force to another object. Potential energy cannot be transferred because it is based on position. Once the position changes, the energy becomes kinetic.
Example: Bowling a ball transferring energy to pins.
What happens to kinetic energy when a ball is thrown into the air?
It is converted into potential energy at the top of the arc.
Kinetic energy can be converted to potential energy when a moving object stops moving.
Potential energy can be converted into kinetic energy when a stationary object starts to move.
What is a practical application of kinetic energy?
Wind turbines converting motion into electrical energy.
Demonstrates renewable energy use.
Define:
chemical energy
Energy stored in the bonds of chemical compounds.
Stored energy is released during chemical reactions, such as combustion.
How is chemical energy used in batteries?
Chemical reactions in the electrolyte create a flow of electrons, generating electricity.
This process involves an anode and cathode.
Fill in the blanks:
Energy is _______ when bonds are broken but _______ when bonds are formed.
absorbed; released
Formation of bonds is an exothermic process while breaking of bonds is an endothermic process.
What process do plants use to store chemical energy?
Photosynthesis
During photosynthesis, carbon dioxide and water are converted into glucose, storing energy.
How do exothermic reactions produce heat?
More energy is released during bond formation than is absorbed during breaking bonds.
Examples include combustion and hand warmers.
In endothermic reactions, more energy is absorbed during breaking bonds.
What are the contents of hand warmers that allows them to produce heat?
- Iron powder
- Water
- Salt
- Carbon
The reaction between iron and oxygen forms rust, releasing heat.
What is an example of chemical energy in daily life?
Burning wood.
Releases stored energy as heat and light.
This is an exothermic process.
What is the primary source of chemical energy in food?
Solar energy
Food energy is ultimately derived from the Sun through various food chains.
What is the difference between electricity and electrical energy?
- Electricity: The flow of charges.
- Electrical energy: The work done by these charges.
Example: Static electricity is electrical energy, not electricity.
Electric energy is measured in Joules, and electricity is measured in Watts.
What is the role of electrons in electrical energy?
Moving electrons create electrical energy.
Electric fields influence movement.
The faster the electrons move, the more electrical energy they create.
Define:
static electricity
Electricity that gathers in one place due to the buildup of electric charges.
It often occurs when two objects are rubbed together.
Example: The charge buildup from rubbing a balloon on hair.
Static electricity is a form of potential energy since charges in static electricity are stationary until discharged.
Define:
current electricity
Electricity that moves from one place to another.
This type of electricity powers homes and electrical devices.
It is a form of kinetic energy.
What is electromagnetism?
The relationship between electricity and magnetism.
Electric current produces a magnetic field, and a changing magnetic field can produce an electric current.
List some common units of electrical energy.
- Ampere (A)
- Coulomb (C)
- Joule (J)
- Watt (W)
- Volt (V)
- Kilowatt-hour (kWh)
These units measure various electrical properties such as current, charge, energy, power, and potential difference.
List five examples of electrical energy.
- Batteries that power electronic devices
- Lightning
- Electrical charges moving through a wire
- Static electricity
- Capacitors storing electric energy
These examples illustrate various forms of electrical energy in different contexts.
Define:
nuclear energy
A form of energy released from the nucleus of atoms.
Defined as energy produced from nuclear processes, distinct from chemical energy.
List two types of nuclear reactions that produce nuclear energy.
- Fission
- Fusion
Fission splits a nucleus, and fusion combines nuclei.
What occurs during nuclear fusion?
Two hydrogen nuclei combine to form a helium nucleus.
This process releases a massive amount of energy due to mass defect.
Mass defect occurs when the mass of the products is less than the mass of the reactants.
What is the primary element involved in nuclear fission?
Uranium
Uranium is a heavy metal with 92 protons and is commonly used in nuclear reactors.
What is the role of water in a nuclear reactor?
- Absorbs heat from a nuclear reaction preventing it from going out of control.
- Helps generate steam for electricity.
What is a nuclear power plant?
A facility that harnesses energy released during a nuclear reaction to generate electricity.
Operates primarily through controlled fission reactions.
The world’s first nuclear power plant switched on in 1951. It powered four 200-watt light bulbs.
List three applications of nuclear energy.
- Powering cities.
- Fueling submarines.
- Fueling space probes.
Nuclear energy is versatile but also produces radioactive waste.
What happens to the byproducts of fission reactions?
They often release radioactive radiation.
The radiation can remain for 1,000 to 10,000 years, which can pose a challenge to waste management.
What is thermal energy?
The energy in an object or system due to the movement of its molecules and atoms.
Thermal energy is often referred to as ‘heat energy.’
What happens to particles as thermal energy increases?
They move faster.
Higher energy levels correspond to increased particle motion.
List the three methods of heat transfer.
- Conduction
- Convection
- Radiation
These describe the movement of thermal energy from a hotter object or system to a colder one.
What is the difference between conduction and convection?
- Conduction: Thermal energy transfer in solids that are in physical contact.
- Convection: Thermal energy transfer in fluids such as water and air.
In conduction, faster particles collide with slower ones, transferring energy.
In convection, warmer particles rise while cooler particles sink.
Which heat transfer method is responsible for keeping the Earth warm?
Radiation
It is a thermal energy transfer method in which energy moves through electromagnetic waves.
Radiant heat from the sun reaches the Earth through electromagnetic waves.
Why does a metal feel colder than wood at the same temperature?
A metal conducts heat away from your hand faster than wood.
Good conductors transfer thermal energy efficiently.
Metal is a good conductor while wood is a poor conductor.
Why does rubbing your hands together warm them?
Due to friction which generates thermal energy.
This is a form of conduction.
Sate the law of conservation of energy.
Energy is neither created nor destroyed; it can change form but the total amount remains constant.
Examples:
- Potential energy being converted into kinetic energy.
- Chemical energy being converted into mechanical energy.
Which energy conversion happens when a person eats food and moves?
Chemical energy is converted into mechanical energy.
This is an everyday example of potential energy changing form to kinetic energy.
A similar energy conversion occurs in a car engine where chemical energy stored in gasoline is converted into mechanical energy.
Describe energy conversion in photosynthesis.
Thermal energy from the sun is converted into chemical energy.
The chemical energy is stored as glucose molecules. This is an example of kinetic energy changing form to potential energy.
What type of energy conversion occurs in a toaster?
Electrical energy is converted into thermal energy.
This is an everyday example of energy conversion between two types of kinetic energies.
