solid, liquid, or gas: particles are very close together
solid
solid, liquid, or gas: particles are closer together than a gas but farther apart than a solid
liquid
solid, liquid, or gas: particles are very far apart
gas
results in change in the side and shape by: tearing, folding, melting, freezing, evaporating, cutting
physical changes
results in any change that forms a new substance at the molecular level by: rotting, burning, cooking, rusting
chemical changes
rapid vaporization of a liquid (liquid to gas)
boiling
water that collects as droplets on a cold surface when humid air is in contact with it (gas to liquid)
condensation
vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase (liquid to gas)
evaporation
a material system made up of two or more different substances that are mixed but are not combined chemically
mixture
what are the two types of mixtures
homogenous and heterogeneous
you cannot see different parts of the mixture- coffee, creamy peanut putter, kool-aid
homogenous mixture
you can see different parts of the mixture- chicken noodle soup, cereal
heterogenous mixture
type of homogenous mixture: one substance of microscopically dispersed insoluble particles is suspended throughout another substance. particles do not settle and cannot be separated out by ordinary filtering- gas, emulsions
colloid
type of heterogenous mixture: contains solid particles that are sufficiently large for sedimentation- organs juice, salad dressing
suspension
type of homogenous mixture: the dissolving agent is the solvent- salt water, sugar water
solutions
measure of acidity or alkalinity of water soluble substances
pH scale
neutral point on pH scale
7
acidity on pH scale
lower than 7
alkalinity on pH scale
above 7
the smallest part of an element that retains its chemical properties. more than 99.94% of their mass is in the nucleus
atom
negatively charged subatomic particles that circle around the atom's nucleus
electrons
neutrally charged subatomic particles that are located in the atom's nucleus
neutrons
positively charged subatomic particles that are located in the atom's nucleus
protons
more than 100 substances that cannot be chemically introverted or broken down into simpler substances and are primary constituents of matter
elements
how an element is identified. it is also the number of protons in the nuclei of its atoms
atomic number
the periodic table can be used in a variety of ways and is broken up several ways:
groups, periods, metals, nonmetals, metalloids, noble gases
vertical/columns on periodic table
groups
horizontal/rows on periodic table
periods
shiny, good conductors of electricity
metals
dull, poor conductors of electricity
nonmetals
dull or shiny, good semiconductors
metalloids
last column on the right of the periodic table
noble gases
in metals, reactivity _____ as you move down and to the left of the periodic table
increases
the smallest particle in a chemical element or compound that has the chemical properties of that element or compound; made up of atoms held together by chemical bonds
molecules
what has the following properties:
cohesion, adhesion, high-specific heat, high heat of evaporation, lower density of ice, high polarity
water is attracted to other molecules. when you put a drop of water close to another drop of water, they combine quickly because they are attracted to each other
cohesion
water is attracted to other molecules. this allows water to stick to roots- capillary action in a plant
adhesion
this allows water to moderate temperature
high-specific heat
this gives off a cooling affect, like when humans swear. the evaporation of water cools off the body
high heat of evaporation
water is less dense than ice, causing ice to float in water
lower density of ice
this makes water a powerful solvent
high polarity
are composed of two or more elements bonded together. they are all molecules, but not all molecules are this
compounds
charged elements or molecules that have lost or gained one or more electrons
ions
two or more forms of the same element that have the same number of protons but a different number of neutrons
isotopes
atom that lost or gained an electron
ion
atom that added or removed a neutron
isotope
any interaction that, when unopposed, will change the motion of an object; can cause an object with mass to change its velocity (including beginning motion from a state of rest)
force
the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other
friction
a state in which opposing forces or influences are balanced
equilibrium
Newton's Laws of Motion
1. an object either remains at rest or continues to move at a constant velocity unless acted upon by a force2. force is equal to the change in motion (mV) per change in time. for content mass, force equals mass times acceleration 3. for every action, there is an equal and opposite reaction
the force exerted by magnets when they attract or repel each other; caused by the motion of electric charges
magnetism
the amount of matter in an object has to its volume
density
an object with a lot of matter in a certain volume has
high density
an object with little matter in the same amount of volume has
low density
the best way to measure density is to use water displacement in a
graduated cylinder
density if found by dividing
the mass of an object by its volume
a property that can be transferred between and among objects; can also be converted into different forms
energy
object is in motion; the actual movement of an object
kinetic energy
the energy possessed by an object or individual by virtue of its position relative to others, stresses within itself, electric charge, and other forced
potential energy
types of energy:
mechanical, electrical, chemical, thermal
types of energy: objects in motion
mechanical
types of energy: moving through the wire
electrical
types of energy: rearrangement of molecular structure
chemical
types of energy: moving particles
thermal
the exchange of thermal energy between physical systems
heat transfer
the transfer of heat by the actual movement of the warmed matter
convection
the transfer of heat from particle to particle
conduction
the transfer of heat from electromagnetic waves through space
radiation
the flow of electric charge
electricity
types of circuits: the components are arranged end to end. the electric current flows through the first component, then through the next component, and so on until it reaches the battery again
series circuits
types of circuits: a circuit with branches that allows multiple applications to happen at once
parallel circuits
good for electricity
conductors
wire, metal, water : conductors or insulators
conductors
bad for electricity
insulators
rubber, cloth, polystyrene (styrofoam): conductors or insulators
insulators
steps to the scientific method
make an observation, ask a question, form a hypothesis, conduct an experiment, analyze the data and draw a conclusions
employ the five senses to interact with phenomena and recoding findings
observe
arrange living and nonliving things based on attributes
classify
make assumptions based on evidence
predict
state a prediction based on evidence
hypothesis
conduct experiments
investigate
a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge
scientific methods
a procedure carried out to refute or validate a hypothesis
experiments
the element manipulated in the experiment
independent variable
what the scientists is measuring during the experiment
dependent variable
the elements of the experiment that a scientists wants to remain constant, so the scientists can observe them as carefully as the dependent variable
control variable
adding what makes an experiment stronger
control group
how graph is used: powerful visual tools that illustrate trends in data over a period of time or a particular correlation
line graph
how graph is used: one can easily compare two or more variables when using this
bar graph
how graph is used: generally used to show percentage or proportional data
pie