pre class monday 10 21 13 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Pre-Class Monday 10-21-13 PowerPoint Presentation
Download Presentation
Pre-Class Monday 10-21-13

Pre-Class Monday 10-21-13

287 Vues Download Presentation
Télécharger la présentation

Pre-Class Monday 10-21-13

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Pre-Class Monday 10-21-13 From breakfast today, write down one thing you ate and label it as: acid, base, or neutral.

  2. Nuclear Changes Chapter 9

  3. Fundamental Forces of Nature • Electromagnetic force – the force between two charged particles (long range) • Strong force – the force that holds neutrons and protons together (short range) • Weak force – the force involved in radioactive decay (short range) • Gravitational force – the force of attraction between two masses (long range)

  4. Strong Force • If pushed close enough together, protons (neutrons) will attract protons (neutrons) • Since it acts over such short distances, protons in very large atoms are only attracted to their nearest neighbors

  5. Radioactivity • When the strong force cannot hold the nucleus together tightly, it can give off matter and energy (this process is known as decaying) • Stable vs. Unstable atoms • Stable = ratio of neutrons to protons of 1 to 1, or for very large atoms 3 to 2 • Unstable = radioactive, usually decaying rapidly • Half-life : the time it takes for half of an element (nucleus) to decay radioactively

  6. Pre-Class Tuesday 10-22-13 How many fundamental forces are there in nature? Or Write: “PLAN”

  7. Types of Nuclear Decay • Alpha Decay • Alpha particle is made of 2 protons and 2 neutrons • Beta Decay • Beta particle is an electron given off during decay • Loses a neutron and gains a proton • Gamma Decay • Most penetrating form of radiation Transmutation – the process when one element becomes another through radioactive decay

  8. Type of Nuclear Radiation

  9. Detecting Radioactivity • Cloud Chambers • Water vapor trapped inside • Water vapor condenses to liquid along path of radioactively decayed particles • Bubble Chambers • Fluid pushed to near boiling • Fluid boils as charged particles pass through it • Electroscopes • Leaves lose their charge in contact with other charged particles • Geiger Counter • Produces electric current from detected particles

  10. Cloud Chamber Bubble Chamber Mass Spectrometer Geiger Counter

  11. Fission is the process of splitting a nucleus into two smaller masses Nuclear reactors use controlled chain reactions to convert nuclear energy into electrical energy Used in nuclear weapons Fusion is the process of combining two smaller masses into one larger nucleus The sun uses thermonuclear fusion to radiate energy outwards Fission (to divide)Fusion (to combine)


  13. Binding Energy • The energy needed to hold an atom together • The energy contained in an atom is directly proportional to its mass • Einstein showed it would be: E = m c2 E is energy (J) M is mass (kg) c is the speed of light (3x108 m/s)

  14. Pre-Class Tuesday 10-02-07 Write down one method we use to detect radioactivity.

  15. Pre-Class Wednesday 10-03-07 Where’s Waldo? When you find him, write: “There he is!” on your paper.

  16. Fossil Fuels • Petroleum (crude oil) • A flammable fluid produced from decaying animals in high pressure and temperature over a long period of time • Mined from underground • Natural Gas • Petroleum that has been turned in to a gas • Always found with petroleum, underground • Coal • A brittle solid produced from decaying plants in in high pressure and temperature over a long period of time • Mined from underground

  17. Fossil Fuel Power Plant

  18. Nuclear Power Plant

  19. Solar Hydroelectric Tidal Wind Geothermal Renewable Sources of Energy

  20. New Materials Through Chemistry

  21. Properties of Metals and Alloys • Good conductors of electricity • Good conductors of heat • Malleable: can be hammered into sheets • Ductile: can be stretched out into wires • Luster: shiny (reflective)

  22. Alloys • A mixture of a metal with one or more other elements • However, the mixture keeps the properties of a metal • Improved strength, lightness, durability, etc. • Example: bronze is made of copper and tin, both found in certain rocks

  23. Ceramics • Materials made from dried clay or clay-like mixtures • Clay is mostly made of sand (silicon and oxygen) and feldspar (crystalline rocks) • Very resistive to acids, bases, salts, water, and oxygen that affect performance

  24. Monomer  Polymer  Composite • Polymer: a repeated pattern of monomers • Monomer: a compound of different elements repeated in a polymer • Synthetic polymers do not occur in nature. • Composite: like an alloy, but the mixture elements are layered or embedded in each other