Unit B: Section 2.0 Flashcards
What did early alchemists try to make gold from?
Earth, Air, Water, Fire
How did the science of chemistry begin?
Alchemists learned that by mixing certain chemicals they could produce surprising results
What happens when wood burns?
The energy in the cellulose molecules is released, turning to heat
What is chemical energy?
The potential energy stored in the chemical bonds of compounds
What is Electrical energy?
The work done by moving charges
What is a Volta pile?
A battery made by stacked layers of 2 different metals such as copper or silver with moistened paper between each layer. A wire is connected from the top and bottom layer.
Who created the Volta pile?
Alessandro Volta
What does the volta pile demonstrate in terms of energy?
A connection between chemical energy and electrical energy
What does an electrical current make?
A magnetic field
How does an electric generator work?
By moving a magnet through a coil of wire
Why does a compass get deflected when an electric current is produced?
Because an electric current produces a magnetic field
What shows that electricity can produce magnetism?
When a compass is near an electric current the compass becomes deflected due to the magnetic field produced
What is evidence that heat energy can be converted into electricty?
When a metal circuit is heated it produced an electric current which caused a compass to be deflected.
What is nuclear energy?
The potential energy stored in the nucleus of an atom?
How was nuclear energy discovered?
A scientist observed atoms spontaneously disintegrating and emit radiation or radiant energy
What is nuclear fission?
When the nucleus of an atom is split and energy is released
When is nuclear fusion?
When the nuclei of 2 atoms join and release energy
What did scientists use to think that the suns energy came from?
They thought it was from chemical burning. But then they realized it would take 5 thousand years for all the energy to be used up
What is solar energy?
A type of energy hydrogen-hydrogen nuclear fission reaction with the release of nuclear energy
How does the suns energy travel to Earth?
As electromagnetic radiation and is converted to other forms of energy such as heat
What do all objects in motion share?
Kinetic energy
What is gravitational potential energy?
An object raised above the Earths surface that has the potential to do work
What is mechanical energy?
The sum of energy of motion and position
What is kinetic energy?
Any object in motion made to do work because of its motion
What did scientists originally believe that heat was?
Heat was an invisible fluid called caloric fluid which flows naturally flows from hot things to cold things
What is thermodynamics?
The science of dealing with the study of the inter-relationships of heat, work, and energy.
What did future scientist believe about heat?
The movement of atoms within a substance determines the thermal energy of the substance.
What is heat?
The transfer of energy from a hot object to a cold object called heat
How are heat and mechanical energy related?
Mechanical energy produces heat energy
Explain Joule’s experiments about the rotating paddles?
-When the weights connecting to the rotating paddles fall they lose gravitational potential energy and the paddle has work done to it so it gains the energy in the form of kinetic energy which transforms into heat
Explain Joule’s experiment about the wooden block?
The wooden block that is falling has kinetic energy until it collides with the other block where it loses its kinetic energy that transforms into heat
What are the types of potential energy?
- Chemical energy
- Gravitational energy
- Nuclear energy
- Elastic energy
What is mass?
- A scalar quantity measured in kilograms (at the doctor’s office)
- Never changes
What is weight?
A vector quantity that measures the force of gravitational attraction on an object in newtons
What does the weight of an object depend on?
The acceleration due to gravity
What is the formula for weight?
W= mg
What is elastic potential energy?
When a force is used to stretch an elastic so that it stores energy
When is potential energy only useful?
When it is converted into another type of energy
Describe chemical potential energy works?
- Energy stored in bonds of chemical compounds
- When chemical reaction takes place and positions of electric charges are altered and energy is released
Where does the word kinetic energy come from?
The greek work kinema which means motion
What are the types of kinetic energy?
- Electrical energy
- Magnetism
- Radiant energy
- Heat energy
- Heat and mechanical energy
What is mechanical energy?
Kinetic energy and mechanical energy combined
What is the law of conservation of energy?
The total amount of energy is a situation remains constant. energy can be converted from one form to another.
What are the four pieces of evidence for energy change?
- Motion
- Change in position
- Change in shape
- Change in temperature
What is the most common energy conversion in the natural world?
- Nuclear fission in the sun releases potential energy
- The potential energy converts into kinetic energy in the form of electromagnetic waves
- When light strikes plants a chemical reaction converts carbon dioxide into and water into glucose and oxygen
- The glucose is potential energy
- When animals eat plants the chemical potential energy is released as carbon dioxide into kinetic energy
What are hydro-electric dams?
A system that converts the energy of moving water into electricity
How does a hydro-electric dam work?
- Water is stored up high and posses gravitational energy
- As water falls the gravitational energy converts to kinetic energy
- When the water reaches the turbines its kinetic energy turns the turbine
- The turbines turn a coil of water in a magnetic field and converts the kinetic energy in into electrical kinetic energy
How does a coal-burning power station work?
- Coal is burned and the chemical potential energy is converted into kinetic heat energy
- The kinetic heat is used to warm the water in a boiler to steam
- The steams kinetic energy is ejected into the turbines causing them to rotate
- The kinetic energy from the steam then moves the turbine which converts into electrical energy.
In nuclear energy reactions do they use fission or fusion?
Fission
How do nuclear reactors work?
- Uranium disintegrates during nuclear fission releasing potential energy
- The potential energy converts into radiation kinetic energy
- The radiation is converted into thermal energy which is used to heat water to steam
- The steams is used to turn turbines
- The turbines turn a coil of wire in a magnetic field which then the kinetic energy is turned into potential energy
What is different about solar cells?
They have no moving parts
What is a solar cell composed of?
2 layer of silicon one with phosphorus and one with boron
How does a solar cell work?
- When sunlight hits the layers it provides energy form one to become positive and one to become negative
- They act as the cells act as a battery and electric current flows
How do fuel cells work?
They convert chemical potential energy from hydrogen into electrical energy and does not require charging as long as it has the fuel
What is kinetic energy?
Energy of a moving object
What is potential energy?
Energy that is stored and held in readiness and has the potential to do work
