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

Nuclear Changes Chapter 9

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)

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

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

Pre-Class Tuesday How many fundamental forces are there in nature? Or Write: “PLAN”

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

Type of Nuclear Radiation

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

Fission (to divide) Fusion (to combine) 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

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 c 2 E is energy (J) M is mass (kg) c is the speed of light (3x10 8 m/s)

Pre-Class Tuesday Write down one method we use to detect radioactivity.

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

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

Fossil Fuel Power Plant

Nuclear Power Plant

Renewable Sources of Energy Solar Hydroelectric Tidal Wind Geothermal

New Materials Through Chemistry

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)

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

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

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