Science midterm vocab
Terms
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- energy
- the ability to do work
- simple machine
- a machine that does work with only one movement; includes the inclined plane, wedge, screw, lever, wheel and axle, and pulley
- cathode
- an electrode with a negative charge
- electron
- negatively charged particle that exists in an electron cloud formation around an atom's nucleus
- gravity
- a non-contact force that every object exerts on every other object; depends on the masses of the objects and the distance between them
- half-life
- time needed for one-half the mass of a sample of a radioactive isotope to decay
- evaporation
- process that takes place when a liquid changes to a gas
- inexahaustible resource
- energy source that can't be used up by humans
- scientist
- a person who works to learn more about the natural world
- nuclear energy
- energy stored in the nucleus of an atom
- fossil fuels
- coal, oil, and natural gas; formed by the effects of heat and pressure on ancient plants and marine organisms
- condensation
- process that takes place when a gas changes to a liquid
- velocity
- speed and direction of a moving body; velocity equals the displacement divided by the time
- law of conservation of energy
- states that energy can change its form but is never created or destroyed
- mechanical advantage
- number of times the input force is multiplied by a machine; equal to the output force divided by the input force
- isotope
- atoms the sam element that have different numbers of neutrons
- screw
- simple machine that is an inclined plane wrapped around a cylinder or post
- input force
- force exerted on a machine
- second law of motion
- states that an object acted on by an unbalanced force will accelerate in the direction of the force with an acceleration equal to the force divided by the object's mass
- element
- matter made of atoms of only one kind
- chemical energy
- energy stored in chemical bonds
- chemical change
- change in which the identity of a substance changes due to its chemical properties and forms a new substance or substances
- wheel and axle
- simple machine made from two circular objects of different diameters that are attached and rotate together
- neutron
- electrically neutral particle that has the same mass as a proton and is found in an atom's nucleus
- speed
- equals the distance traveled divided by the time needed to travel that distance
- first law of motion
- states that an object will remain at rest or move in a straight line at a constant speed unless it is acted upon by an outside force
- kinetic energy
- energy an object has due to its motion
- renewable resource
- energy resource that is replenished continually
- atom
- the smallest particle of an element that retains all the properties of that element
- anode
- an electrode with a positive charge
- law of conversation of mass
- the total mass of the matter is the same before and after a physical or chemical change
- generator
- device that transfroms kinetic energy into electrical energy
- radiant energy
- energy that travels in the form of waves
- inertia
- the tendancy of an object to resist a change in its motion
- meter
- SI unit of distance equal to approximately 40in.
- inclined plane
- simple machine that is a flat, slpoed surface or ramp
- hypothesis
- prediction or statement that can be tested and may be formed by prior knowledge, any previous observations, and new information
- dependent variable
- factor that may change as a result of changes purposely made to the independent variable
- pulley
- simple machine made from a grooved wheel with a rope or cable wrapped arpund the groove
- mechanical energy
- the sum of an object's kinetic and potential energy
- efficiency
- equals the output work divided by the input work; expressed as a percentage
- nonrewable resource
- energy resource that is used up much faster than it can be replaced
- balanced forces
- forces acting on an object that combine to make the net force equal zero, so that no change occurs in the object's motion
- vaporization
- the process by which a liquid changes into a gas
- work
- is done when a force exerted on an object causes that object to move some distance; equal to force times distance; measured in joules
- thermal energy
- sum of the kinetic and potential energy of particles in an object due to their random motion
- friction
- force between two surfaces in contact that resists the sliding of the surfaces past each other
- matter
- anything that has mass and takes up space
- third law of motion
- states that forces act in equal but opposite pairs
- acceleration
- change in velocity divided by the amount of time needed for that change to take place; occurs when an object speeds up, slows down, or changes direction
- solution
- a mixture of two or more substances uniformaly mixed throughout but no bonded together
- physical change
- change in which the form or appearance of matter changes, but not its composition
- sublimation
- the process by which a solid changes directly to a gas
- electrical energy
- energy carried by electirc current
- fulcrum
- the fixed point about which a lever pivots
- alternative resource
- new, renewable, or inexhaustible energy source; includes solar energy, wind, and geothermal energy
- compound machine
- machine made up of a combination of two or more simple machines
- potential energy
- energy stored in an object due to its position
- control
- sample that is treated like other experimental groups except that the independent variable is not appiled to it
- air resistance
- a contact force that opposes the motion of objects moving in air
- proton
- positivly charged particle in the nucleus of an atom
- non-contact force
- a force that is exerted by one object on another when the objects are not touching
- constant
- variable that stays the same during an experiment
- technology
- application of science to make useful products and tools, such as computers
- output force
- force exerted by a machine
- mass number
- the sum of neutrons and protons in the nucleus of an atom
- transmutation
- the change of one element into another through radioactive decay
- lever
- simple machine consisting of a rigid rod or plank that pivots or rotates about a fixed point called the fulcrum
- heat
- thermal energy that moves from a higher temperature to lower temperature
- observation
- gathering information through the use of one or more senses
- science
- process used to investigate what is happening around us in order to solve problems or answer questions; part of everyday life
- wedge
- simple machine consisting of an inclined plane that moves; can have one or two sloping sides
- force
- push or pull one object exerts on another; has a size and direction
- power
- rate at which work is done; equal to the work done divided by the time it takes to do the work; measured in watts
- independent variable
- factor that is intentionally varied by the experimenter
- net force
- the combination of all the forces acting on an object
- unbalanced forces
- forces acting on the object that combine to make the net force not equal to zero, and cause a change in the object's motion
- biotechnology
- technology applied to living organisms
- atomic number
- number of protons in the nucleus of an atom of a given element
- mass
- a measure of the amount of matter in an object
- nucleus
- small region of space at the center of the atom that contains protons and neutrons