Transcript Matter and Energy

Matter & Energy
Chapter 2
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What are Matter and Energy?
matter – is material such as rocks, water, air with mass and
occupying space.
energy – is what makes matter move!
Energy is measured in many different units.
The metric unit of energy used by scientists is:
4.184 joules = 1 calorie
What is Matter?
 Matter is anything that has
mass and takes up space.
 Objects made of matter have
physical properties.
 Physical properties are
characteristics of a substance
that can be seen or measured.
Color, hardness, and taste are
examples of physical
properties.
The physical properties
of this orange are that it’s
round, orange, and soft.
Partner Activity
 Take a moment with
your partner to name
the physical
properties of the
pictured object.
Check your answers.
Pyramid Physical Properties
 Triangular
 Purple
 Shiny
 Hard
 Heavy
Measuring Mass
 Mass is the amount of matter in an object.
 Mass is measured using a balance in grams.
 Mass of an object is always the same.
balance
What is Weight?
 Weight is a measure of the pull of gravity on
an object.
 Weight of an object can change.
 Example:
 A car that weighs about 2,698 lbs on earth weighs
about 450 lbs on the moon due the difference in
the force of gravity.
Measuring Mass by Volume
 Volume is the amount of
space that an object
takes up.
 Liquids can be measured
using a graduated
cylinder (see photo).
 Solids can be measured
by using a calculation.
 Length x width x height
Volume
 What if the object is an
odd shape?
 Volume of irregular
shapes can be found by
placing them in water.
 Then, measure the
amount of water that is
displaced.
Click to watch and learn.
Density
 Density is the amount
of matter in a certain
volume.
 The density of an
object always stays
the same.
 Density = mass /
volume
Click to watch and learn.
3 States of Matter
 There are 3 states of matter that you are familiar with.
 Solid
 Liquid
 Gas
 Visit BBC’s website on the 3 states of mater.
Phases of Matter
 the phases
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solid
liquid
gas
plasma
depend on how tightly
bound the atoms and/or
molecules are
 As temperature
increases, these bonds
are loosened:
Temperature vs. Heat
 Temperature is the
average kinetic energy.
 Heat (thermal energy) is
the total kinetic energy.
lower T
higher T
same T
less heat
more heat
Temperature Scales
Solidrock
 Has a shape and a
definite volume.
 Feels firm when you
touch it.
 The particles are
packed closely
together.
 Examples
candy
helmet
Liquid
ocean
 Has a definite volume
but no definite shape.
 The particles of a
liquid move more
freely.
 Can change shape.
 Examples
soup
soda
Gas
 Gas does not have a definite shape or
volume.
 The particles are freer to move around and
move the fastest.
 Gas flows and takes the shape of the
container.
Changes Between States of Matter
 All substances can
change states.
 Liquids can freeze.
Freezing changes a
liquid to a solid.
Changes Between States of Matter
 Melting changes a
solid to a liquid.
 Boiling changes a
substance from a
liquid to a gas.
What is a Solution?
 A solution is a mixture in which different kind of matter
mixed even with each other.
 Example: Adding sugar to water
 A solution can only be made when one substance
dissolves.
 Click to visit the mixture lab.
Physical Changes
 Physical changes occur when matter changes its
property but not its chemical nature.
 Physical property changes are any change in
size, shape or state of a substance.
Sugar can undergo many
physical changes. Even
though each form is different,
they are still sugar.
Physical Change
Chemical Changes
 Burning is an example
of a chemical change.
 Light and warmth are
released. Smoke, ash,
and hot gases are
produced.
Chemical Changes
 Chemical changes are changes matter undergoes
when it becomes new or different matter.
 To identify a chemical change look for signs such as
color change, bubbling and fizzing, light production,
smoke, and presence of heat.
What is Energy?
 Energy is the ability to do
work.
 Energy is the ability to
cause changes in matter.
 Light, sound, heat, and
electricity are forms of
energy.
 Three categories of
energy are:
1. Kinetic Energy
2. Potential Energy
3. Radiant Energy
Three Basic Types of Energy
 kinetic
 energy of motion
 potential
 stored energy
 radiant
 energy transported by light
Energy can change from one form to another.
Kinetic Energy
 Amount of kinetic energy of a moving object
= 1/2 mv2
[if mass (m) is in kg & velocity (v) is in m/s, energy is in joules]
 On the microscopic level
 the average kinetic energy of the particles within a
substance is called the temperature.
 it is dominated by the velocities of the particles.
Potential Energy
 energy is stored in matter itself
 this mass-energy is what would be released if an amount
of mass, m, were converted into energy
E = mc2
[ c = 3 x 108 m/s is the speed of light; m is in kg, then E is in joules]
Potential Energy
 gravitational potential energy is the
energy which an object stores due to
its ability to fall
 It depends on:
 the object’s mass (m)
 the strength of gravity (g)
 the distance which it falls (d)
g
m
d
Conservation of Energy
 Energy can be neither created nor destroyed.
 It merely changes its form or is exchanged between
objects.
 This principle (or law) is fundamental to science.
 The total energy content of the Universe was determined
in the Big Bang and remains the same today.
Energy Sources
 It comes from many
different sources.
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Solar
Chemical
Water
Nuclear
Wind
Natural Gas
Fossil Fuels
Solar Energy
 This is energy that comes
from the sun.
 All living things depend
on this energy.
 Does not damage the
environment.
 Can be used for heat and
electricity.
Click to watch and learn.
Chemical Energy
 Energy stored in a
substance and
released during a
chemical reaction
such as burning
wood, coal, or oil.
Hydroelectric (Water) Energy
 Energy the comes from
moving water.
 Dams are built to store
water and generate
electricity.
 Hydroelectric power is
produced as water passes
through a dam, and into a
river below. The more
water that passes
through a dam, the more
energy is produced.
Nuclear Energy
 Energy that comes
from splitting
atoms of
radioactive
materials, such as
uranium
 Used to produce
electricity.
Wind Energy
 Wind is air moving
around.
 Wind is used to
generate electricity.
 Windmills are used to
create this electricity.
 Safe for the
environment.
Fossil Fuels
 Fuels (coal, oil, natural
gas, etc.) that result from
the compression of
ancient plant and animal
life formed over millions
of years.
 Fossil fuels are oil, coal,
natural gas, and uranium.
Nonrenewable Energy
 This means that this type of energy cannot be
made again.
 An energy source that we are using up and
cannot recreate in a short period of time.
 Nonrenewable Energy Sources:
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nuclear
oil
coal
natural gas
Renewable Energy
 This type of energy can be replenished.
 An energy source that we can use over and over
again.
 Renewable Energy Sources:
 solar
 wind
 water
Electric Energy
 Electric energy is the
energy produced by
the movement of
electrons.
 When an object gains
or loses electrons, it
has an electric
charge.
Electric Energy
 When an object has a charge, it attracts objects with
the opposite charge.
 This is called an electrical force.
 An electric current is the flow of electrons from
negatively charged objects to positively charged
objects.
Electric Current
 An electric current is the flow of electrons.
 To light a light bulb or run a computer, you need a
continuous electric current.
 A battery or generator can be the source of electrons.
Electric Energy
 Conductors of electricity are materials that
carry electrons easily from one terminal to
another.
 A conductor is used in the wire that makes an
electric circuit. An electric circuit is any path in
which electrons can flow.