matter & chemistry - mr. celia's science...
TRANSCRIPT
Matter & Chemistry
OK, you’ve probably seen the
Bill Nye video and have learned
that matter is everything and all
stuff. That’s right. Everything
around you is matter. In fact,
anything that has weight and
takes up space is matter.
Write it down:
• Matter – Anything that has mass and
volume.
• All objects are made of matter.
Forms of matter
• Matter comes in three common forms or phases:
*SOLID *LIQUID *GAS
• Two additional, less known phases are:
*PLASMA
*BOSE-EINSTEIN CONDENSATE
Solids • Solids have a definite
shape and a definite volume.
• This means that solids keep their shapes and take up a set amount of space under normal conditions.
• Rocks, ice, salt crystals, & wood are all examples of solids.
Liquids
• Liquids do not hold their shapes; they take the shape of their container.
• Liquids have a definite volume. This means that a liter of water is a liter of water no matter what container it is in.
• Water, Pepsi, orange juice & oil are all examples of liquids
Gases • Gases also take the
shape of their
containers.
• Gases do not have a
definite volume. They
will expand out to fill
the entire container.
(Think of a balloon)
• Oxygen, water vapor,
Carbon Dioxide are all
examples of gases.
Plasma – the weird fourth stage
• A plasma is a gas that is made
of atoms that are electrically
charged (positive and negative
ions). A plasma conducts
electrical currents.
It is estimated that
99% of the matter
in the observable
universe is in the
plasma state
Bose-Einstein Condensate In a B-E condensate,
the atoms in the solid
begin to merge into each
other.
The atoms go from
being trillions of
individuals to one big
clump.
This happens only at a
few billionths of a
degree above absolute
zero.
Think of the M&M’s melted together as
the atoms in a B-E Condensate.
Molecules inside matter
• The molecules inside matter are in
constant motion.
• Speed
• Slower Faster
• B.E.C. Solid Liquid Gas Plasma
Solid
Liquid
Gas
Changing Phase
• The atoms and molecules within matter
are in constant motion.
• The energy that causes this is called
kinetic energy – the energy of motion.
• Atoms and molecules with
more kinetic energy
moves faster and further
apart.
• Atoms and molecules with
less kinetic energy
moves slowly and stay
close together.
• The TOTAL energy in all of the particles in a sample of matter is called Thermal energy.
• Thermal energy depends upon the number of particles in the sample as well as the energy each particle has.
• If you average the total kinetic energy of each individual particle in the sample, you have the sample’s temperature. (This will be discussed later in the unit)
• Matter can change state when thermal
energy is absorbed or released. This is
called, believe it or not, “A Change in
State”
Molecular motion in
Solids / Liquids / Gasses
Ice
Liquid water
Steam
Rephrasing/Reviewing
• Kinetic energy is the energy that causes particles in a sample of matter to move.
• Thermal energy is the total kinetic energy of all particles in the sample of matter.
• Temperature is the average kinetic energy of the particles in the sample of matter.
• When a cold object and a hot object come in
contact, the thermal energy is transferred from
the hot to the cool object.
• Thus, when an object is heated, the particles in it
begin to move faster, increasing its temperature.
• Heat is defined as the movement of thermal
energy from a warmer object to a cooler one.
Phase change diagram
Solid Liquid Gas
Phase change diagram
Solid Liquid Gas
Melting Evaporation
Condensation Freezing
Sublimation
Crystalization or desublimation
Add Heat Add Heat
Remove Heat Remove Heat
Vocab Review • Melting: Solid becoming a liquid. Add energy.
• Evaporation: Liquid becoming a gas. Add energy.
• Freezing: Liquid becoming a solid. Remove energy.
• Condensation: Gas becoming a liquid. Remove energy.
More vocab . • Sublimation: Solid becoming a gas, skipping the
liquid phase. Add energy.
• Crystallization or Desublimation: Gas becoming
a solid, skipping the liquid phase. Remove
energy.
• General Terms:
• Solidification: to become a solid.
• Liquefaction: to become a liquid.
• Vaporization: to become a gas.
Sublimation and Crystallization
Properties of matter
• Matter is
described using
three properties
– physical,
chemical, and
biological.
Physical Properties
• Physical properties of matter that
can be observed and measured
using your five senses, without
changing the composition of a
substance.
Physical Properties
• Examples of physical properties include:
• size
• color
• shape and texture
• state of matter
• melting and boiling points
• does it conduct electricity?
• mass, volume, density
More Vocabulary • Solubility: Ability to dissolve in water or
another liquid.
• Malleable: Easily pounded into shapes.
• Ductile: Easily made into wire.
• Viscosity: Ability of a liquid to flow.
Examples: High Viscosity = Corn syrup.
Chemical Properties
• Chemical properties of matter are often
not easily observed. Chemical properties
describe how the chemicals inside the
matter react with other chemicals.
• When trying to figure out the chemical
properties of matter ask yourself some
questions:
Chemical property questions:
• Will it burn?
– Paper will, concrete will not. Therefore, a
chemical property of paper is that it will
burn. A chemical property of concrete is
that it will not burn.
Can I eat it? - You can consume an orange and get
nutrition from it. You can physically eat a
rock, but it does nothing for you. Thus, a
chemical property of an orange is that it is
edible.
Chemical properties
• More often than not,
chemical properties
indicate how the
chemical will react
with other
chemicals. We will
discuss this further
in the unit.
Biological properties
• Biological properties of matter tell whether
it is living, non-living, or dead.
Measuring Matter Matters!
• As we said, physical properties of matter
include measurements.
• The important measurements of matter we
are going to deal with now include Mass,
Volume, Density, and Temperature.
MASS
• Mass: A measurement of the amount of
matter inside an object.
• Mass is often thought of being the same
as weight. This is not true. Weight
depends upon the gravitational force
exerted upon an object.
• Weight - The downward force exerted on
an object due to gravity.
Mass vs. Weight
• Mass is measured using a balance.
• Weight is measured using a scale.
Volume
• How much soda fits into a 2-liter bottle?
• Why does the tub overflow if it is too full
when you climb in?
Volume
• Volume can answer both of these
questions.
• Volume is the amount of space taken
up by an object OR the amount of
space inside a container.
Volume Facts:
• Volume is measured in some form of liters,
commonly Milliliters (ml).
• Volume can also be measured in cubic
centimeters. 1 cm3 water = 1ml water.
• Many items are sold by volume such as
gasoline, soda, milk, and shampoo.
• The average volume of a bathtub is 40
gallons or 151.4 liters.
Most Important fact!!! • When dealing
with volume, the
number one rule
is: NO TWO
OBJECTS CAN
OCCUPY THE
SAME SPACE
AT THE SAME
TIME!
Volume
• Only the bottom
bags are taking
up space on the
pallet.
• The box and the
soda bottle both
have space
inside them.
Measuring volume
• When measuring volume, you can use
different methods depending upon the
shape of the item.
• If you are attempting to find the volume of
a cubic item, you only need to measure
the length, width, and height of the object
and multiply them (volume = L x W x H)
Measuring with a ruler
Length
Width
Height
Length x Width x
Height
If
L = 10cm,
W= 10 cm, and
H = 10 cm,
what is the volume
of this Rubic’s
cube?
Measuring with a ruler
• 10 x 10 x 10 = 1000 cm3
• The answer is given in cubic
centimeters, cm3.
• Remember: 1 cm3 water = 1ml water.
Measuring irregular shapes
• What if you wanted to find out the volume
of a rock? A Ball? A ring?
Measuring irregular shapes
• To measure an object with an odd or
irregular shape, you cannot use a ruler.
• The method used for finding the volume of
irregular shapes is called the Water
Displacement Method.
• The tools required for this method are a
graduated cylinder and water.
Measuring
irregular shapes • 1) Find a graduated
cylinder that will be large enough to fit the object(s) being measured.
• 2) Fill this graduated cylinder enough so that when placed in the graduated cylinder, the object will be fully submerged in the water.
Measuring irregular
shapes
• 3) After filling the graduated cylinder , record the volume of the water.
• 4) Next, carefully place the object in the graduated cylinder and record the new volume of water.
Measuring irregular shapes
• 5) To find the
volume of the
irregularly shaped
object, subtract the
volume of the water
alone from the
volume of the water
and object.
• What is
the
volume
of this
stone?
Important fact!!
• Meniscus - the
curve seen at the
top of a liquid
because of its
attraction to its
container.
Important fact!!
• A meniscus is what happens when you put
a liquid into a container.
• When you put water in a beaker or test
tube, you see a curved surface.
• With most liquids, the attractive force
between the liquid and the container is
greater than the attraction between the
individual liquid molecules. So the liquid
"sticks" to the side of the container.
Meniscus
Water has a slight electric charge which
causes it to stick to the side of the glass. This
is called the meniscus.
Density
• Density is defined as: An object’s mass per unit of volume. In other words, what is its mass compared to its size.
• An objects density tells us how tightly packed the molecules inside are.
• The more tightly packed the
molecules of an object, liquid
or gas are, the more dense
we say they are.
Density
• Density is usually expressed in
grams/milliliters or grams/cubic
centimeters.
• The standard for density is water. Water’s
density is 1 gram/milliliter. That means
that 1 ml of water will have a mass of 1
gram.
Density
• Which item below would be the most dense? Which
would be the least dense?
• WHY?
v
Finding Density
• In order to find the density of an object, you must first know its mass and volume.
• To find density, you divide the object’s mass by the volume and that tells you the density.
• The formula for density is:
Density = Mass/volume or D=M/V
Examples of Density
• The mass of a rock is 20g and its volume
is 4ml. What is its density?
•The mass of a rock is 20g and its volume is 4ml. What is its density?
Sink or Float? • Any object that has a density
of less than 1g/ml is going to float when placed in water.
• Any object with a density that is greater than 1g/ml is going to sink.
• With this in mind, how could you guess the density of a piece of foam?
Oops!
Sink or Float?
• LESS dense objects (things that are less packed together) float on top of things that are MORE dense (more packed together); this includes things like liquids and gases and circumstances like a cheese doodle in rice.
• As long as an object is less dense than the substance it is in, it will float. If an object is too dense it will sink to the bottom.
• The size of the object does not matter!
– *LARGE, light (less dense) object will FLOAT.
– *Small, heavy (more dense) objects will sink.
Formula fun!
• To find density: D=M/V
• To find Mass: M= D x V
• To find Volume: V= M/D
Review
• What tool is used to determine mass?
• What method would you use to find the volume of a basketball?
• What is the formula for finding density?
• How is mass different from weight?
Temperature
• Temperature is the average kinetic
energy of the particles in the sample of
matter.
• As you remember from Bill Nye, all
molecules of any substance are constantly
moving.
• The faster the molecules are moving, the
warmer the substance is.
Temperature
• Scientists use a thermometer to
measure temperature.
Temperature
• Temperature is
measured with
several
different scales.
Temperature - °F
• In the United States, we use the Fahrenheit Scale °F.
• In the Fahrenheit scale, – 320F is the freezing point of water
– 2120F is the boiling point of water.
– -459.670F is Absolute Zero.
Temperature - °C
• the Celsius scale is used by almost every other country 0C
• In the Celsius scale,
– 00C is the freezing point of water
– 100 0C is the boiling point of water.
– -273.150C is Absolute Zero.
Temperature - K
• Scientists use a different scale called the Kelvin Scale K. ( NOTE: the 0 symbol is not used in the Kelvin scale)
• In the Kelvin Scale,
273.15 K is the freezing point of water 373.15 K in the boiling point of water.
0 K is Absolute Zero.
Converting scales
• Kelvin to Celsius °C = K − 273.15
• Celsius to Kelvin K = °C + 273.15
• Kelvin to Fahrenheit °F = K × 9 ⁄ 5 − 459.67
• Fahrenheit to Kelvin K = (°F + 459.67) × 5 ⁄ 9
• Celsius to Fahrenheit °F = °C x 1.8 + 32
• Fahrenheit to Celsius °C = °F - 32 / 1.8
Temperature
• Heat moves in a predictable flow from warmer objects to cooler objects until all objects are at the same temperature.
• In other words, heat moves from high concentration (the heat source) to low concentration. COLD NEVER MOVES!
• Coldness is simply an absence of heat, or slow molecular motion.
• Heat moves in three ways:
• Conduction
• Convection
• Radiation
Movement of Heat - Conduction
• Conduction is the transfer of heat from one object to another through direct contact. (touching)
• Conduction is the simplest form of heat transfer.
Movement of Heat - Conduction
• The rapidly moving atoms of the hot
burner bump against the atoms that make
up the pan, making those atoms move
faster.
Movement of Heat #2 -
Convection • Convection is the method of heat transfer in
liquids or gases by means of currents.
• As particles get heated they start to move faster. As the particles move faster, they move farther apart and the object becomes less dense.
• Less dense objects move to the surface of more dense objects. That explains why the warmer water when swimming is at the top. This also explains how a hot air balloon works.
Convection in a Pot
Water at the bottom
warms, becomes
less dense and rises
to the top.
• As the water at the
bottom of the beaker
gets hotter, it rises to
the top. This makes
the cooler water sink
to the bottom where
It begins to heat.
When it gets hot
enough, it rises and
continues the cycle.
Movement of Heat - Convection • Most likely your home is heated by convection. A
radiator heats up the air near it. When this air rises, the cool air sinks and begins to warm up. When it rises it is replaced again by cooler air.
Conduction and Convection
Movement of Heat - Radiation
• Radiation transfers heat through space to
other objects by infrared waves.
• Heat sources such as the sun or a hot
wood stove send out these invisible
infrared waves.
Movement of Heat - Radiation
The earth receives heat from the sun by
radiation.
Movement of Heat - Radiation
• The heat from the sun can warm the ground
even though it is 186,000 miles away!!
• All things emit
some form of
heat radiation.
This can be seen
with an infrared
camera. Hotter
parts are red, and
cooler are blue.
Movement of Heat - Radiation
Sitting by a
fire, you feel
heat waves.
Conductors and insulators
Conductors
• Some materials readily accept the transfer of heat energy.
• Any material that allows heat to pass through it easily is called a Conductor.
• Heat travels easily through some materials like copper, aluminum, and most metals.
Conductors
• Why are pots and pans made out
of metal and not wood or plastic?
Insulators
• Some materials do not allow heat to pass through very well. These are called insulators.
• The handles on pots and pans are often made of wood and plastic since these materials do not allow heat to pass through them easily.
• Liquids, gases, and most non-metallic solid materials like wood and plastic are good examples of insulators.
Conductor Insulator
• Conductors move heat easily because the
atoms and molecules in a conductor are
generally more dense than insulators.
Buy New Windows!
Why do you think people use
wooden spoons when cooking?
What purpose do the pot holders serve?
Coats, hats, and
gloves trap our body
heat close to us. The
materials inside them
insulate us from the
cold.
Down Coats
• The feathers in a
down coat or
comforter trap the
air molecules in the
many fibers and
prevent heat from
moving.
Insulating your Home saves
Money and Energy!
• Poorly Insulated Home Well Insulated Home
• As air molecules attempt
to move through the
fiberglass, the fibers
slow them down or trap
them, slowing or
stopping convection
currents and the
movement of heat.
• As air molecules attempt
to move through the
empty space, there is
nothing to slow them
down or stop convection
currents and the
movement of heat.
• The better insulated your home is, the less
heat loss that occurs through the walls.
• The less heat loss you have, the warmer
your house stays and the furnace doesn’t
run as often.
• If your furnace doesn’t run as often, you
save electricity, fuel, and MONEY!!
• If you save money, you have more to buy
your favorite science teacher presents!!
Review:
• What is Heat?
• What is temperature?
• How does heat move?
• How is a conductor different from an insulator?
• 98.6 0 F = ___0C? 100 K = ___ 0C?
• What else do YOU feel needs review?
What is Matter made of?
• Matter is composed of tiny particles
called atoms.
• Now would be a good time to view the
exciting, spectacular, Power Point
show entitled “Atoms”