Transcript Properties of Matter: Physical Properties

Cscope
Unit 3
Lesson 1
TEKS
 The student knows that relationships exist
between properties of matter and its components.
 7B Research and describe the historical
development of the atomic theory.
Key Understandings and Guiding Questions
 -The development of the atomic theory comes
from the contributions of several scientists.
 — How has atomic theory evolved over time, and
why is it not considered a law? -
Vocabulary of Instruction
 theory
 law
 atomic theory
Mystery Boxes
 Get in groups of 4
 Get a set of mystery boxes 1-3
 Do not open or peek inside boxes.
 Do your best to figure out what is inside
each without looking.
 Write down your conclusion for each box
How did you come to your conclusions?
 What senses did you use?
 Did you use any tools?
 [Such as a triple beam balance.]

Hand the boxes in, do not open them
Boxes answers?
 I’m Not telling you the answers
 CONFUSED?
 Scientist don’t know the answers
they must do there best without all
the answers
A Theory is an explanation of a natural event.
Theories are sometimes our best guess, and are often
revised as we discover new information.
Example; the formation of the Universe
If proven- over time it can become a law.
Example of a theory- Kinetic Theory
 The KINETIC MOLECULAR THEORY states that
molecules are in constant motion.
 The molecules are in motion
 and hit the all side of the balloon
 Equally, causing it to expand
 equally
Scientific Law
A law states a summary of a repeated
observation about a natural event.
The sun always rises
in the East
Law
Hot wheels are nearly exact replicas
of cars but smaller
They are models of cars
they can help us understand what a
type of car looks like
A MODEL is a replica of an object or event.
MODELS MAY BE:
drawings
mental pictures
a set of rules
physical objects
computer pictures
Identify some models in our classroom….
Identify some things in the classroom that are NOT
models…
Model Activity
 Groups of 4
 Number off 1-4 at each table
 1- read directions
 2- locate the next piece
 3- put the piece in the correct place
 4- checker to verify correctness
 Build the model that is at your table.
 Follow the directions
Models
 In the case of atoms, scientists use large models to
explain something that is very small
 Models of the atom were used to explain data or
facts that were gathered experimentally.
 So, these models are also theories
Research project
 Atomic Theory Timeline
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(use your hand out)
Create a timeline you have 1 day to research, 1 day to
construct it
IncludeScientists who contributed to the atomic theory
Significant discoveries
New inventions which helped scientists in their studies
Draw the atoms at each stage
•
•
Use the following information to complete the lecture handout.
On tomorrow’s quiz, you will be expected to…
draw the atomic models
match scientists to their experiments and discoveries
place the models in chronological order
Democritus (400 B.C.)
• Proposed that matter was
composed of tiny indivisible
particles
• Not based on experimental
data
• Greek: atomos
Alchemy (next 2000 years)
• Mixture of science and mysticism.
• Lab procedures were developed, but alchemists did not perform controlled
experiments like true scientists.
John Dalton (1807)
 British Schoolteacher
 based his theory on others’
experimental data
 Billiard Ball Model
 atom is a
uniform,
solid sphere
John Dalton
Dalton’s Four Postulates
1. Elements are composed of small indivisible
particles called atoms.
2. Atoms of the same element are identical.
Atoms of different elements are different.
3. Atoms of different elements combine together
in simple proportions to create a compound.
4. In a chemical reaction, atoms are rearranged,
but not changed.
Henri Becquerel (1896)
 Discovered radioactivity
 spontaneous emission of
radiation from the nucleus
 Three types:
 alpha () - positive
 beta () - negative
 gamma () - neutral
J. J. Thomson (1903)
 Cathode Ray Tube Experiments
 beam of negative particles
 Discovered Electrons
 negative particles within the
atom
 Plum-pudding Model
J. J. Thomson (1903)
Plum-pudding Model
 positive sphere (pudding)
with
negative electrons (plums)
dispersed throughout
Ernest Rutherford (1911)
 Gold Foil Experiment
 Discovered the nucleus
 dense, positive charge in the
center of the atom
 Nuclear Model
Ernest Rutherford (1911)
 Nuclear Model
 dense, positive nucleus surrounded by
negative electrons
Rutherford’s gold foil experiment
http://www.shsu.edu/%7Echm_tgc/sounds/pushmovies
/l2ruther.gif - source of animation
Niels Bohr (1913)
 Bright-Line Spectrum
 tried to explain presence of
specific colors in hydrogen’s
spectrum
 Energy Levels
 electrons can only exist in
specific energy states
 Planetary Model
Niels Bohr (1913)
Bright-line spectrum
 Planetary Model
 electrons move in circular orbits
within specific energy levels
Erwin Schrödinger (1926)
 Quantum mechanics
 electrons can only exist in
specified energy states
 Electron cloud model
 orbital: region around the
nucleus where e- are likely to be
found
Erwin Schrödinger (1926)
Electron Cloud Model (orbital)
 dots represent probability of finding an e-
not actual electrons
James Chadwick (1932)
 Discovered neutrons
 neutral particles in the nucleus
of an atom
 Joliot-Curie Experiments
 based his theory on their
experimental evidence
James Chadwick (1932)
Neutron Model
 revision of Rutherford’s Nuclear Model
Current atomic model
 Electron Cloud Model- nucleus with
protons and neutrons in the center
 Electrons in clouds around the nucleus-
very large area compared to the nucleus
 Electrons move too fast to find exact
location at any one time
 Atoms are mostly empty space!
http://www.teachersdomain.org/resource
/phy03.sci.phys.matter.atoms/
Modern Models of Atoms
QUARKS
 Protons, and neutrons are made up of smaller
particles- quarks
 Quarks- smallest particles- make up protons,
neutrons, and electrons- 6 types
 up, down, top, bottom, strange and charm
 To study quarks- accelerate charged particles to high
speeds and cause them to collide with protons,
breaking the proton
QUARKS

http://en.wikipedia.org/wiki/Particle_accelerator
 A proton is made up of 2 up quarks and 1 down quark =
charge of +1
 a neutron contains 1 up quark and 2 down quarks, yielding
a net charge of 0
 All you’ve learned about atomic structure is just a model
 Model- help you visualize or understand something too
large or small to see all at once

http://www.teachersdomain.org/resources/phy03/sci/phys/matter/atoms/index.html
http://www.fearofphysics.com/Atom/atom1.html
Atomic Theory Model
 the smallest unit of an element,
But this theory will change
 having all the characteristics of that
elementas we gather new
again
 consisting of a dense, central, positively
information
charged nucleus
 surrounded by a system of electrons.
JOKE
 A neutron walks into a restaurant and orders a coke.
 As she is about to leave, she asks the waiter how
much she owes.
 The waiter replies "For you, No Charge! ,!!"
Atoms Family
Album
 a Story OF aTOMS
Atoms Family Album
 Around the Nucleus Arcade, you will find a
series of roadways that are used by another
member of the Atoms Family, Enraged
Elliott Electron.
 Elliott races madly around the Arcade on his
bright red chrome plated Harley-Davidson.
He rides so fast that no one can be sure
where he is at any time.
 Elliott is much smaller than Patty and Nelda
and he is always angry because these
bigger relatives will not let him in the
Arcade.
 He has a frown on his face, eyes that are
squinted with anger, and a very negative (-)
attitude.
Elliot Electron
Atoms Family Album
++
 In the center of Matterville, there is a place
called the Nucleus Arcade, where two
members of the Atoms Family like to hang out.
 Perky Patty Proton, like her sisters, is quite
large with a huge smile and eyes that sparkle
(+).
 Patty is always happy and has a very positive
personality. Nerdy Nelda Neutron is large like
Patty, but she has a boring, flat mouth and
eyes with zero expression (o).
 Her family is very apathetic and neutral about
everything. Patty, Nelda, and their sisters
spend all their time at the arcade.
Patty Proton
Nelda Neutron
Atoms Family Album
 The first energy street can
only hold only two Electron
brothers.
 The second energy street,
called the Energy Freeway,
can hold 8 brothers.
 The third energy street,
called the Energy
Superhighway, can hold 18
of the brothers.
Atom worksheet
 Complete the diagram of the Bohr model of the
atom
 Cut it out
 glue it into your notebook
AlternatePoster;
Atom
A
 Get in groups of 4 (count off 1-4)
 Jobs -1 recorder , 2 draw, 3 research, 4 spokes person
 Get a big sheet of paper
 Make a poster about atoms
 Draw and label atom, you have 10 minutes
 Topic-What do you know/remember about the atom?
 Spokesperson show poster and tell us about it
JOKE
 Two atoms are walking down the street.
 Says one atom to the other, "Hey! I think I lost an
electron!"
 The other says, "Are you sure??"
 "Yes, I'm positive!"