Matter Unit Vocabulary
With Definitions
1. Matter – is basically anything that takes up space. Put it another way, it is anything made
of stuff. The dictionary says:
a. Something that occupies space and can be perceived by one or more senses; a
physical body, a physical substance, or the universe as a whole.
b. Physics. Something that has mass and exists as a solid, liquid, gas, or plasma…
2. State or Phase of Matter: the forms in which matter (stuff) can exist. All of the stuff in
the universe that takes up space can be divided into one of the states of matter. For now,
we will only look at three of them: 1. Solids, like wood, steel and glass 2. Liquids, like
water, syrup and gasoline, and 3. Gases like air (which is really many gases including:
oxygen, carbon dioxide, and nitrogen.) All matter can be found in any of the phases
depending on the temperature and pressure, so steel can be found as a solid, liquid and
under very unusual conditions gas.
3. Phase change or Change in State: when matter changes from solid to liquid to gas in
any way. Add heat to go from S to L to G, take away heat to go from G to L to S.
4. Mass: to simplify, the mass of a thing is how much matter or stuff is in it. Physicists say
it is “the measure of an object's resistance to changes in either the speed or direction of its
motion.” If you think about it something that has more stuff or matter in it will be harder
to move than something with only a little stuff in it. Compare moving your little brother
(a little bit of stuff) and moving me (a lot of stuff.) Mass is measured in pounds, ounces,
grams and kilograms.
5. Weight: a measurement of the force of gravity on an object. The larger the mass, the
more gravity pulls it, so the greater the weight. The smaller the mass, the less gravity
pulls it, so the smaller the weight. Weight IS NOT the same as mass. Your weight is
much different on the moon than on earth, yet your mass remains the same. We use
different tools to measure mass and weight. Weight uses the same units of measure as
Mass.
6. Volume: the amount of space an object takes up. Volume is measured in pints, cups,
quarts, and gallons in the customary English system and in Liters and Milliliters om the
metric system.
7. Density: the amount of matter that is contained in a unit of volume. Something that has
5 grams of matter per liter is much less dense than one with 500 grams per liter.
8. Solid: the phase of matter that has a definite shape and volume; not liquid or gaseous
9. Liquid: the phase of matter that has a definite volume, but not a definite shape, liquids
are fluid (as water), meaning they flow from one place to another and take the shape of
their container BUT do not expand to fill their container. Liquids can be thick like corn
syrup or thin like water (scientists call this viscosity.) Even under a lot of pressure,
liquids are only slightly compressible.
10. Gas: the phase of matter that has no definite shape or volume, gases expand to fill
whatever container they are in. They are not viscous (thick) and can be compressed by
forcing them into small rigid containers.
11. Evaporation: When a liquid is converted or changed into a gas (also called a “vapor.”)
This is one of the changes in the phase or state of matter.
12. Condensation: When a gas is converted or changed into a liquid. This is one of the
changes in the phase or state of matter. You see this when water vapor condenses on
your mirror when you shower. The water gas (vapor) changes to liquid water when it is
cooled by touching the cool mirror surface.
13. Freeze: When a liquid is converted or changed into a solid. This is one of the changes in
the phase or state of matter.
14. Melt: When a solid is converted or changed into a liquid. This is one of the changes in
the phase or state of matter.
15. Freezing point: the temperature at which a liquid changes to solid at a particular
pressure.
16. Melting point: the temperature at which a solid changes to liquid at a particular pressure.
17. Temperature: is a measurement of the hotness or coldness of a piece of matter.
Scientists say it is average amount of kinetic (movement) energy that something has.
18. Atom: a Greek word that was first used by a Greek scientist named Democritus. It
means that which can not be cut. Democritus figured if you cut something into smaller
and smaller pieces, you would finally get to a piece so small it could not be cut any more.
This is the atom. After about 2000 years, scientists discovered that even atoms can be
cut. They are made of much smaller particles: the Proton, Neutron, and electron (which
are made of Quarks, which some think are made of even smaller things called “strings.”
19. Nucleus: the protons and neutrons in the center of an atom.
20. Proton: a small sub-atomic (smaller than an atom) that is in the nucleus and has a
POSITIVE electrical charge.
21. Sub-atomic particles: particles that are smaller than an atom. Particles used to make
atoms.
22. Electron: a small sub-atomic that is in the nucleus and has a NEGATIVE electrical
charge.
23. Neutron: a small sub-atomic (smaller than an atom) that is in the nucleus and has a
NEUTRAL electrical charge.
24. Molecule: the smallest piece of a compound that still has the physical properties of that
compound.
25. Meter
26. Centimeter
27. Liter
28. Milliliter
29. Gram
30. Kilogram
These are Metric system units of
measurement that you must know how to use
from practice.
31. Solution:
32. Solute
33. Homogenous – uniform in nature. It is the same throughout without and clearly
different material in the mixture. Example- ice tea – it is all the same throughout.
34. Heterogeneous – made of a number of different things. Clearly distinguishable parts like
salad or mixed cereal.
35. Suspension - heterogeneous fluid containing solid particles that are sufficiently large for
sedimentation an example is silt mixed in water. When stirred it will look fairly
homogenous (but it is heterogeneous on close inspection), but the silt will settle and form
sediment after a time.
36. Colloid – a type of chemical mixture where one substance is dispersed evenly throughout
another. Milk is a perfect example. The particles of the dispersed substance are only
suspended in the mixture, unlike a true solution where they are completely dissolved
within. The true solution is generally transparent – for example sugar dissolved in water,
The particles in a colloid are larger than in a solution - small enough to be dispersed
evenly and maintain a homogenous appearance - but large enough to scatter light and not
dissolve. This makes colloids cloudy in appearance.
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