Six

Plate Tectonics

Oceans

Astronomy: Gravity, Stars and Galaxies

Energy, Heat, and Energy Transfer

The Human Body

Science Biographies

The surface of the earth The surface of the earth is in constant movement. The present features of earth come from its ongoing history. After the sun was formed, matter cooled creating the planets. The continents were once joined (Pangaea).

Layered structure of the earth Crust: surface layer of mainly basalt or granite, 5 to 25 miles thick Mantle: 1,800 miles thick, rock of intermediate density, moves very slowly Outer core: liquid iron and nickel Inner core: solid iron and nickel, 800 miles thick, about 7,000 degrees C

" Crust movements The surface of earth is made up of rigid plates that are in constant motion. Plates move because molten rock rises and falls under the crust causing slowly flowing currents under the plates. Plates move at speeds ranging from 1 to 4 inches (5-10 centimeters) per year. Earthquakes usually occur where stress has been built up by plates moving in opposite directions against each other. Earthquakes cause waves (vibrations) which have: focus, the point below the surface where the quake begins epicenter, the point on the surface above the focus Severity of ground shaking is measured on the Richter scale; each unit on the scale represents a tenfold severity increase"

" Volcanoes usually occur where plates are pulling apart or coming together, but some occur at holes (hot spots) in the crust away from plate boundaries. As plates move over these hot spots, they cause chains of volcanoes and island chains like the Hawaiian Islands."

"Evidence for long-term movement of plates includes fit of continents and matches of rock types, fossils, and structures; ocean floor age and topography; ancient climate zones; locations of earthquakes, volcanoes, and mountain ranges; magnetic directions in ancient rocks."

"Marine life Life zones are determined by the depth to which light can penetrate making photosynthesis possible, and by the availability of nutrients. The bottom (benthic zone) extends from sunlit continental shelf to dark sparsely populated depths. Shallow lighted water extending over continental shelf contains 90% of marine species. Pelagic zone: water in open oceans Classification of marine life Bottom-living (benthic) such as kelp and mollusks Free-swimming (nekton) such as fish and whales Small drifting plants and animals (plankton), which are the dominant life and food source of the ocean The basis for most marine life is phytoplankton (plant-plankton), which carry on photosynthesis near surface; contrast zooplankton (animal plankton). Most deepwater life depends on rain of organic matter from above. The densest concentration of marine life is found in surface waters, such as those off Chile, where nutrient-rich water wells up to the bright surface. "

" Gravity: an attractive force between objects Newton’s law of universal gravitation: Between any two objects in the universe there is an attractive force, gravity, which grows greater as the objects move closer to each other. How gravity keeps the planets in orbit"

" Stars The sun is a star. Kinds of stars (by size): giants, dwarfs, pulsars Supernova; black holes Apparent movement of stars caused by rotation of the earth Constellations: visual groupings of stars, for example, Big Dipper, Orion Astronomical distance measured in light years"

"Galaxies The Milky Way is our galaxy; the Andromeda Galaxy is closest to the Milky Way. Quasars are the most distant visible objects (because the brightest)."

Energy

Heat

Physical Change: Energy Transfer

The circulatory and lymphatic systems Briefly review from grade 4: circulatory system Lymph, lymph nodes, white cells, tonsils Blood pressure, hardening and clogging of arteries

The immune system fights infections from bacteria, viruses, fungi. White cells, antibodies, antigens Vaccines, communicable and non-communicable diseases, epidemics Bacterial diseases: tetanus, typhoid, tuberculosis; antibiotics like penicillin, discovered by Alexander Fleming Viral diseases: common cold, chicken pox, mononucleosis, rabies, polio, AIDS

Marie Curie (advances in science of radioactivity; discovered the elements polonium and radium)

Lewis Howard Latimer (worked with Alexander Graham Bell on drawings of Bell’s invention, the telephone; improved Thomas Edison’s light bulb)

Isaac Newton (known for advances in physics; outlined laws of gravity and invented the telescope)

Alfred Wegener (known for theory that the continents were once joined together and split apart to form the continents; now known as “the continental drift”)

Six forms of energy: mechanical, heat, electrical, wave, chemical, nuclear

The many forms of energy are interchangeable, for example, gasoline in a car, windmills, hydroelectric plants.

Sources of energy: for example, heat (coal, natural gas, solar, atomic, geothermal, and thermonuclear), mechanical motion (such as falling water, wind)

Fossil fuels: a finite resource Carbon, coal, oil, natural gas Environmental impact of fossil fuels: carbon dioxide and global warming theory, greenhouse effect, oil spills, acid rain

Nuclear energy Uranium, fission, nuclear reactor, radioactive waste Nuclear power plants: safety and accidents (for example, Three Mile Island, Chernobyl)

Heat and temperature: how vigorously atoms are moving and colliding

Heat and temperature: how vigorously atoms are moving and colliding

States of matter (solid, liquid, gas) in terms of molecular motion In gases, loosely packed atoms and molecules move independently and collide often. Volume and shape change readily. In liquids, atoms and molecules are more loosely packed than in solids and can move past each other. Liquids change shape readily but resist change in volume. In solids, atoms and molecules are more tightly packed and can only vibrate. Solids resist change in shape and volume. 

Most substances are solid at low temperatures, liquid at medium temperatures, and gaseous at high temperatures.

A change of phase is a physical change (no new substance is produced).

Matter can be made to change phases by adding or removing energy.

Expansion and contraction Expansion is adding heat energy to a substance, which causes the molecules to move more quickly and the substance to expand. Contraction is when a substance loses heat energy, the molecules slow down, and the substance contracts. Water as a special case: water expands when it changes from a liquid to a solid

Changing phases: condensation; freezing; melting; boiling Different amounts of energy are required to change the phase of different substances. Each substance has its own melting and boiling point. The freezing point and boiling point of water (in degrees Celsius and Fahrenheit)

Distillation: separation of mixtures of liquids with different boiling points.