Transcript History of the Atom Activity - Ms. Ose's Chemistry Website

History of the Atom Activity
• Objectives:
– Today I will be able to:
• Explore the nature of science by completing an activity
• Research a scientist to understand the history of the
atom
• Informal assessment – monitoring group
interactions and questions
• Formal assessment – analyzing student
responses to the exit ticket
• Common Core Connection
– Build Strong Content Knowledge
– Value Evidence
– Come to understand other perspectives and
Lesson Sequence
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Evaluate: Warm – Up
Explore: History of the Atom Research
Enage: Construction of Timeline
Elaborate: Gallery Walk
Evaluate: Exit Ticket
Warm - Up
• Using all of the pieces, except the piece with
the x, arrange the pieces into the shape of a
square.
• You discover a missing piece to the puzzle.
Work by yourself to fit the new piece in and
make a new square.
• How does this relate to making a discovery in
science?
Warm - Up
• Complete the half sheet on atomic changes
• Use the word bank on the worksheet to
complete the questions
Warm - Up
• Complete the Ions/ Isotope WS
– Don’t worry its not a quiz 
Warm - Up
• What did the gold foil experiment help
determine?
• What is the difference between the Bohr and
Schrodinger models of the atom?
Objective
• Today I will be able to:
– Explore the nature of science by researching the
history of the atom
– Research a scientist to understand the history of
the atom
Homework
• Review the information on your scientist
• Continue researching
Agenda
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Warm – Up
History of the Atom Research
Construction of Analogies
Make a Flip Book
Exit Ticket
History of the Atom Research
Each member of the group will use
textbooks and the computers to
research their two assigned scientists
Analogies
Make an analogy
• Work with your group to create a real-life
analogy for the Dalton, Thomson, Bohr and
Schrodinger Models of the atom
• Look at Ms. Ose’s example for guidance
• Share analogies with the class
History of the Atom Analogy
Dalton’s Model
Thomson’s Model
History of the Atom Analogy
• Bohr Model
– Sugar cookie with chocolate chips in rings around
the outside
• Schrodinger Model
– Sugar cookie dipped in melted chocolate
Make a flip book
The image of your analogy must be
included in the flip book
Flipbook Requirements
• For Dalton, Thompson, Rutherford, Bohr,
Schrodinger
– Describe their model of the atom
– Draw a picture of their model of the atom
– Write and draw a picture of your analogy
– For Thompson and Rutherford – Describe the
experiment
– For Dalton – Write the pieces of the atomic theory
History of the Atom Notes
Democritus (400 BC)
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Greek Philosopher
All matter is composed of tiny, indivisible
parts called “atomos”
He said you cannot cut a piece of matter
infinitely, but at some point you would get
the smallest piece of matter possible.
Said “atomos” could not be divided any
further
John Dalton (1803)
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School Teacher
Studied the ratios in which elements combine in a chemical reaction
Dalton’s Atomic Theory
All matter is composed of tiny indivisible parts called atoms (they can be
broken down further, although properties will not be retained)
Atoms of the same element are exactly alike, atoms of different
elements are different (not all atoms of the same element have the
same mass – isotopes)
Atoms can combine in simple ratios to form compounds
Atoms are neither created nor destroyed
- Atoms cannot be destroyed, they simply rearrange in a chemical
change, therefore the total amount of atoms remains the same
John Dalton (1800’s)
J.J. Thomson (1897)
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Discovered the electron
Worked with Cathode Ray Tubes
Discovered particles with a negative charge, electrons –
knew they were negative charges by the deflection of
the beam from a magnet
He also was able to estimate that the mass of the
electron was equal to about 1/1800 of the mass of a
hydrogen atom.
His discovery of the electron won the Nobel Prize in
1906.
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He created the “plum pudding model” of the atom.
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“Pudding” is positive
Electrons are embedded within the “pudding”
J.J. Thomson (1897)
J.J. Thomson (1897)
• Discovered that the beam going between the anode and cathode could
be deflected by bringing a magnet close to the cathode ray tube. The
deflection that Thomson observed showed that the beam must have
been made up of negatively charged particles
• He showed that the production of the cathode ray was not dependent on
the type of gas in the tube, or the type of metal used for the electrodes.
He concluded that these particles were part of every atom.
Robert Millikan (1909)
• measured the charge of an electron using the oil
drop experiment.
• x-rays gave the oil a negative electron
• 1.60x10^-19 coulomb is the charge of an electron
• using Thomson’s charge to mass ratio, he determined
the mass of the electron is 9.11x10^-28g
Oil Drop Experiment
Ernest Rutherford (1911)
• Born in New Zealand 1871-1937
• Tested Thomson’s theory of atomic structure with the “gold
foil” experiment in 1910.
• Bombarded thin gold foil with a beam of ‘alpha’ particles.
• If the positive charge was evenly spread out, the beam should
have easily passed through.
• All of the positive charge and most of the mass of an atom are
concentrated in a small core, called the nucleus.
• Gold Foil Experiment (alpha scattering)
• he determined that an atom’s positive charge and most of its
mass was concentrated in the core (most of the atom is empty
space)
• he named the core “the nucleus”
Rutherford’s Gold Foil Experiment
Rutherford’s Model of the Atom
• Contained a positive nucleus
• Electrons were around the outside of the
nucleus
Niels Bohr (1914)
• Start of the Quantum Mechanical Model
• Electrons are particles
• Electrons occupy different fields or energy levels
• Based on the fact that atoms appeared to release
fixed amounts (quantized) of energy when exposed
to heat
• When an electron is exposed to an energy source, it
jumps to a higher energy level
• When the electron eventually falls back to its original
position, energy is released
Niels Bohr (1914)
Werner Heisenberg
• Principle of uncertainty
– We cannot know both the location and the
momentum of an electron
– The more we know about an electron’s position,
the less uncertain we are
Erwin Schrödinger (1926)
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Based on Heisenberg's principle of
uncertainty
Shows where electrons will probably be
found by using the waves they leave behind
Electrons are waves
Update to the Quantum Mechanical Model
Sometimes called the Electron Cloud Model
Erwin Schrödinger (1926)
Exit Ticket
• Write two facts that you learned today about
a scientist that another group member
researched
Exit Ticket
• What does this activity teach us about the
nature of scientific knowledge?