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 UniverseIf 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
Hot wheels are nearly exact replicas of cars but smallerThey are models of carsthey 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 (use your hand out) • Create a timeline you have 1 day to research, 1 day to construct it • Include- • Scientists who contributed to the atomic theory • Significant discoveries • New inventions which helped scientists in their studies • Draw the atoms at each stage
Atomic Structure Timeline 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) • Planetary Model • electrons move in circular orbits within specific energy levels Bright-line spectrum
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 AtomsQUARKS • 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
A closer look at quantum mechanics: http://www.fearofphysics.com/Atom/atom1.html
Atomic Theory Model But this theory will change again as we gather new information • the smallest unit of an element, • having all the characteristics of that element • consisting of a dense, central, positively 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
Alternate- Poster; 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!"