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Matter and Molecules
- 1. Welcome to Physical Science
- 2. Lab Notebooks • Make it your own! • Add stickers, color with Sharpie markers, etc. • Include your NAME on the FRONT and inside front cover • Add a "Table of Contents" to the first page • Then leave several blank pages for future entries • 4 or 5 pages is enough • Record notes, lab data, and weekly quiz answers • You can also leave me notes/questions • Put notebooks in box at end of class • I will grade quizzes & labs each week • You take it home at end of year
- 3. Navigating the Science Wiki Page First Priority: •Log In to iwonderwhy.pbworks.com •Request Access •Check your Email •Create an account •Use YOUR name •Upload a picture of yourself or a graphic that tells everyone something about you but DO NOT use a picture of someone else as your avatar.
- 4. Navigating the Science Wiki Page Front Page: •ALL Class Links for everything I teach •Click on YOUR class: PHYSICAL SCIENCE •"What Is This?" Corner •prizes will vary •Announcements •Assignments •Due in 1 week •Resources •How to Get Help What's This???
- 5. Branches of Science Science Life Science Physical Science Biology Microbiology Genetics Anatomy Physiology Evolution Botany Zoology Embryology Immunology Marine Biology Physics & Chemistry Chemistry Organic & Biochemistry Physics Biophysics & Robotics Computer Programs/Circuitry Engineering & Design Thermodynamics Quantum Mechanics Electromagnetism Cosmology Earth & Space Science Astronomy Aeronautics Ecology Hydrology Geology Meteorology Paleontology Oceanography Seismology Volcanology •Physics & Chemistry are foundational to understanding all sciences
- 6. Matter - What is it? ...and what is it NOT? • Matter is anything that: • has mass • takes up space • All matter is made up of atoms • more than 100 different kinds
- 7. Experiment 1.1 Density: mass and volume • Which of these rods has the greatest mass? • Write down your hypothesis • Observation: • What do you know? • What do you want to know more about? • Hypothesis: • What do you think will happen (& why)? • Experiment: • Record the data • What happened? • Conclusion: • Was your hypothesis correct? • What's next?
- 8. Mass - a weighty subject! • Mass • a measure of how much physical "stuff" an object has • mass ≠weight • weight is gravity's pull on matter • more mass = more weight • more gravity = more weight • SI unit = kg Advanced Topic
- 9. • Atoms are the smallest unit of particles comprising matter • every atom is made up of • at least one positively charged proton • one or more neutrons (except hydrogen) • one or more shells of negatively charged electrons • Most of what makes up an atom is EMPTY SPACE!!! What is matter made of? in a dense, central nucleus Atoms are mostly empty space!
- 10. Nuclear Particles • Protons • located in the nucleus of an atom • each proton has a positive (+1) charge • "heavy" (has a significant mass) • The number of protons in an atom determines the type of element • 1 proton = Hydrogen • 3 protons = Lithium • 8 protons = Oxygen • # of protons can be found on the periodic chart as the atomic number p+
- 11. Nuclear Particles • Neutrons • located in the nucleus • neutrons have no charge (0) • "heavy" (has a significant mass) n0 • The number of neutrons varies within elements • # of neutrons can be determined using the periodic chart • atomic mass = average weight of protons & neutrons combined (taking into account all its isotopes) • neutrons = atomic mass (rounded to nearest whole #) minus the atomic number
- 12. Orbiting Particlese- • The number of electrons usually equals the number of protons (atomic #) • When the # of negative charges (electrons) equals # of positive charges (protons), they balance out. • Sometimes there are extra or missing electrons. • This results in an ion (net (-) or (+) charge on the atom) • Electrons • zip around outside the nucleus • impossible to know the exact position or velocity • each electron has a negative (-1) charge • "light" (contributes virtually nothing to the mass of an atom)
- 13. Electrons in Motion • Electrons are happiest • in pairs • with full shells • Lone electrons are unstable and highly reactive! • Energy Levels (also called electron shells or orbitals) show where electrons are likely to spend most of their time. • Each level holds a different maximum number of electrons. • Lower (innermost) levels are filled before outer levels. • A better description of where electrons hang out is the term "electron cloud"
- 14. Atoms vs. Molecules • Compounds are pure substances made from a single type of molecule (two or more different combined elements) • ratios remain constant (there will always be twice as much Hydrogen as Oxygen in water) • i.e. carbon dioxide, sodium chloride (salt), iron oxide (rust), ammonia (NH3), water, chalk (CaCH3) • Two or more atoms joined together make a molecule • can be same or different kind of atom • different properties than the individual atoms that form it Oxygen Molecule O2 Water Molecule H2OOxygen atom O • Elements are pure substances made from only one type of atom • i.e. gold, carbon, helium, neon, sulfur • all listed in the Periodic Table of the Elements
- 15. Mixtures - What examples can you think of? • A mixture is made of different substances (two or more compounds) that can be physically separated • Separate substances mix, but keep their individual characteristics • contain different ratios of substances • examples: • some fruit salad might have more grapes than bananas • some granite has more feldspar in with the mica than others Granite • How can substances be separated out of mixtures? • by hand or with tweezers • evaporation or distillation • filtering • settling in layers (centrifuge) • magnets
- 16. Demonstration 1.2 Element, Compound, or Mixture? • Table Salt • Sodium (Na) + Chlorine (Cl) = NaCl • Saltwater • NaCl + H2O (2hydrogen + 1oxygen) • Sand • Silicon (Si) + 2 Oxygen (O) = Silicon Dioxide (SiO2) • Also made up of different minerals formed from other elements • Ferro-fluid • Iron filings + mineral oil (long chains of hydrogen and carbon atoms derived from petroleum) • Diamond • Carbon Substance Prediction Actual Salt element? Saltwater Sand Ferro- fluid Diamond
- 17. Mixtures - Fruit Salad vs. Whipped Cream • Heterogeneous mixtures are unevenly mixed • different substances clump together • easily identified as separate substances • examples: granite, soil, sand, salad dressing, OJ • Homogeneous mixtures are evenly mixed • particles are uniformly dispersed (spread out) • even with a microscope, different substances can't be identified • examples: air, brass, antifreeze, whipped cream, apple juice Advanced Topic
- 18. Solutions • A solution is a homogeneous mixture in which one or more solutes (particles of a substance) are distributed uniformly throughout another substance (the solvent) • solutes & solvents can be solids, liquids or gases • in solution, solute and solvent must be of the same state of matter • the solvent is the substance in greatest quantity in the solution • Examples: • air is a solution of several different gases (O2, CO2, Ar) equally distributed in Nitrogen gas • alloys (such as sterling silver or dental fillings) are solid solutions • carbonated drinks are sugar, flavorings and carbon dioxide gas solutes uniformly dispersed in water Advanced Topic
- 19. Summing up the "Matter"
- 20. Demonstration 1.2 Pure Substance or Mixture? • Table Salt • Sodium (Na) + Chlorine (Cl) = NaCl • Pure COMPOUND • Saltwater • NaCl + H2O (2hydrogen + 1oxygen) • Homogeneous MIXTURE (SOLUTION) • Sand • Silicon Dioxide (SiO2) and many minerals formed from other elements • Heterogeneous MIXTURE • Ferro-fluid • Iron filings + mineral oil (long chains of hydrogen and carbon atoms derived from petroleum) • Heterogeneous MIXTURE • Diamond • Carbon • Pure ELEMENT Substance Prediction Actual Salt Pure COMPOUND Saltwater HOMO- GENEOUS Mixture Sand HETERO- GENEOUS Mixture Ferro- fluid HETERO- GENEOUS Mixture Diamond Pure ELEMENT
Editor's Notes
- White Board: draw an atom! Or WHAT IS MATTER? (to assess familiarity with atomic structure) Opening Activity: decorate LAB NOTEBOOKS and label with name.
- What makes something like a bike (hard, cool, metalic, smooth) different than a tree (rough, flamable, fibrous)? The atoms that make up each object have different properties. Things that cannot be physically described or measured are usually NOT comprised of matter (kindness, God, hunger, ideas). In scientific terms, things like sound waves and light contain a certain amount of energy, but not mass and therefore are not comprised of matter. Dark matter is a concept in theoretical physics of something that has mass but no volume.
- Experiment vs. Demonstration discussion: https://sciencebob.com/category/science-fair-ideas/ Density bars, scale, lab notebooks optional: graduated cylinders & water - explain difference between volume, mass, and density - focus on mass and discuss the scientific method Each material is made up of different atoms, held together in different combinations Rods include: brass, a homogeneous mixture (and solution) of primarily copper (67%) and zinc (33%) aluminum, a metal element nylon, a plastic polymer (very long, repeating molecules) PVC (poly vinyl chloride), another polymer made from chlorine and petroleum products clear acrylic, yet another plastic polymer from which Plexiglas is made (also from petroleum)
- This can be confusing, because in everyday language, when we ask, "how much does that weight?" we are REALLY (in scientific terms) asking what its mass it.
- Quick review on rounding to a whole number: Jeanne's method: circle the one's place number draw arrow to number on the right if it's 5 or above, the circled number is raised one digit if it's 4 or below, the circled number STAYS THE SAME In the example here, round the mass to 96. Neutrons = 96-42 = 54 Isotopes: One of two or more atoms that have the same atomic number (the same number of protons) but a different number of neutrons. Carbon 12, the most common form of carbon, has six protons and six neutrons, whereas carbon 14 has six protons and eight neutrons. Isotopes of a given element typically behave alike chemically. With the exception of hydrogen, elements found on Earth generally have the same number of protons and neutrons; heavier and lighter isotopes (with more or fewer neutrons) are often unstable and undergo radioactive decay .
- Elephant vs. mouse in weight to compare proton/neutron to electron.
- Don't go into too much detail at this point about valence electrons and reactivity.
- chalk = calcium carbonite (CaCH3) ammonia = NH3
- Jell-O is a colloid: a heterogeneous mixture with particles larger than those in a solution, but not large enough to settle out. Milk, paint, and mayo are, too (and aerosols). Water can be chemically separated into oxygen and hydrogen but is not a mixture because those elements cannot be physically separated.
- Materials: salt, ferro-fluid, sand, beaker and water source
- brass = copper + zinc vinegar = acetic acid and water
- In a salt solution, Na and Cl dissociates into ions in order to form a homogenous mixture. CuSO4 = copper sulfate
- Challenge students to find a pure element and bring it to class next week. Cast iron skillet has ~2% carbon. Graphite pencil is carbon + clay. Silver or gold jewelery usually has quite a bit of other metals thrown in to make it stronger (less soft/malleable). Lead bullets or fishing weights have less than 5% other metals. A helium balloon, magnesium fire starter, copper pipes/fittings, diamond ring, aluminum foil, argon and tungsten in light bulbs.
- Materials: salt (kosher or rock salt along with table salt), black construction paper squares, hand lenses, microscope, ferro-fluid Sand