Chapter 4: Making Sense of The Universe: Matter, Energy

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Chapter 4 Making Sense of The Universe Matter,
Energy Gravity
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What Is Matter?

• Matter is the stuff that makes up our things
• Matter is composed of atoms and their
  constituents
• These elements combine to form the molecules of
  life
• Matter has MASS - Mass is an intrinsic property
  of matter

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What Is Energy?

• Energy comes in different forms - Kinetic
  (motion)- Potential (stored)- Radiative
  (electromagnetic)
• Mass can be turned into Energy
• Energy can become Mass
• Emc2

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Matter is composed of atoms
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• The Periodic Chart

These elements all have unique chemical
properties, based on the number of protons,
neutrons and electrons they are composed of. If
you add or remove neutrons from the most common
form of an element, you create Isotopes. Strippin
g electrons from an atom is called Ionization.
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Phases of Matter

• Solid
• Liquid
• Gas
• Plasma

The state changes as you increase the temperature
(add energy)
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Atoms Orbits

• Matter appears solid, but is composed of mostly
  empty space!
• Electrons orbit atoms in clouds, with higher
  energy electrons in farther orbits

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Atomic Energy States
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Potential Energy

• Potential Energy is the energy something has just
  because it has mass and is where it is
• Think of a boulder on a hill as an example, when
  it rolls down it turns potential energy into
  Kinetic Energy(Umgh)
• Simply by having mass that can be turned into
  energy is potential

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Kinetic Energy

• When mass is moved it is Kinetic Energy (T1/2
  mv2)
• Adding energy to a system, i.e. as heat, will
  make the atoms more energetic and they will move
  more, colliding with other atoms this is
  Kinetic Motion
• Temperature Energy

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Conservation of Energy

• In a closed system, the sum total of the energy
  is conserved

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The UniversalLaws of Motion
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Motion

• What is the difference between Speed, Velocity
  Acceleration?
• Speed is a scalar, that means that it is how fast
  you go, but without specific direction
• Velocity is a vector, it gives speed and
  direction
• Acceleration is found when an object is speeding
  up or slowing down

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Formulae

• v ?x/ ?t
• a ?v/ ?t
• g 9.81 m/s2

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Mass Momentum

• Mass is an intrinsic property of matter. The
  atomic mass is invariant, regardless of your
  gravitational field (or speed)
• Weight is a Force, it changes depending on your
  gravitational field
• Momentum is mass x velocity, it tells you that
  big-fast things are harder to stop than
  small-slow things.
• p mv

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Newtons Laws of Motion

• First Law An object at rest remains at rest, and
  an object in motion remains in motion, unless
  acted upon by an external force
• Second Law F ma ?p/ ?tForce depends on rate
  of change of momentum.
• Third Law For every force, there is an equal and
  opposite force

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Conservation of Momentum

• Newtons laws imply the concept of conservation
  of momentum. The total momentum in a system is
  conserved.
• Angular momentum acts on a body in orbit around
  another, held by the gravitational force. In the
  absence of net torque, the angular momentum
  remains constant.angular momentum mvr

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Newtons Universal Law of Gravitation

• Every mass attracts other mass through the force
  called gravity
• The force of attraction between any two objects
  is directly proportional to the product of their
  masses
• The force of attraction between two objects
  decreases with the square of the distance between
  their centers
• Fg GM1M2/d2
• (note that G is the gravitational constant)

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Newtons Influence

• Some 70 years after Kepler published his three
  laws of orbital motion, Newton was able to
  explain why they held true!
• Science strives to observe, determine
  relationships and eventually discover why
  things work the way they do.
• Newtons laws remained unchallenged until an
  upstart named Albert Einstein developed a general
  theory of gravity that was more precise in 1905.

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Gravity Rules!

• The gravitational influence of the Moon cause the
  tides
• Leaving the surface of Earth takes a lot of
  energy, it is like crawling out of a deep well.
  The escape velocity is about 40,000 km/hr. (pg
  135)
• While the other fundamental forces
  (electromagnetic, strong and weak) are much
  stronger, their range is short and the motion of
  the stars and galaxies are bound by gravity.

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Free Fall

• Why are astronauts weightless in space?They are
  in a constant state of free fall.The Force from
  gravity in the space station from Earth is not
  much less than on the surface! (p.121)