Look at the picture to the right. The earth is tilted about 23.5 degrees. Hemispheres are separated by the equator. This means that when the Northern Hemisphere is

tilted toward the sun, it has a larger amount of direct sunlight, more hours of sunlight per day (therefore more energy strikes it=heat), causing summer.

Half a year later, when it tilts away from the sun, there is less direct sunlight, less hours of sunlight per day (less energy), causing cooler temperatures: winter.

The Northern and Southern Hemispheres have opposite seasons; you can see by looking at the tilt of the lower hemisphere.

Lunar cycle: appearance of phases of the Moon asviewed from Earth, as the Moon orbits the Earthabout once every 28 days.

4 Moon Quarters = 4 weeks = 1 month

Waxing — to increase in size gradually

Crescent — having a concave shape (sliver)

Waning — to decrease in size gradually

Gibbous — more than half

The moon has no natural luminous capabilities (it does not shine like the sun). Moon only reflects light from the sun, like a mirror. The moon phases are displayed in the image to the left . Notice that during the new moon, the moon appears dark. Actually, during a new moon the far side of the moon (side away from us) would be lit, except from Earth, we can’t see the far side. The diagram only shows what you would see if the sun and moon were in those positions relative to the Earth. The positions of the sun, moon and Earth also affect the earth’s oceans and cause changes in the tides.

Moon phases:

New moon (T): cannot see lit side of the moon

Waxing crescent: crescent that is getting larger

First Quarter (Q): half of the moon visible Waxing Gibbous: most of the moon is

visible Full moon (R): can see all of the moon Waning gibbous: most of the moon is visible (opposite of

waxing) Last or Third Quarter (S): other half of the moon is visible Waning crescent: crescent that is getting smaller

Tides: cyclic rise and fall in sea level caused by the pull of themoon’s gravity on Earth. Sun’s gravitational pull is less.

Lunar Eclipse: When our view of the moon is blocked; the Earthis between the Sun and moonMoon is in Earth’s shadow

Solar Eclipse: When the moon blocks out the sun; the moon isbetween the Earth and SunSmall area on Earth is in

Spring Tides:

Earth, sun, and moon are lined up (Full

or New Moon phase). High tides are

really high, low tides are really low.

Neap Tides:

Moon and sun are at

right angles (1st and 3rd

quarters)

Less difference between

high and low tides.

8.7 The student knows the effects resulting from cyclical movements of the Sun, Earth, and Moon. The student is expected to (A) model and

illustrate how the tilted Earth rotates on its axis, causing day and night and revolves around the Sun causing changes in seasons,

(B) demonstrate and predict the sequence of events in the lunar cycle, and (C) relate the position of the Moon and Sun to their effect on ocean tides.

Readiness — Knowledge and Skills Science 8 — STAAR Review

Category 3

Earth and Space

Rotate — to spin on an axis. The earth rotates once each day (24 hours) on its imaginary axis (line through N and S poles)

Revolve — move around another object; the path = “orbit”. Earth revolves around the sun once per year (365 1/4 days).

Calc!

On Your Own—Evaluate the diagram to the left. Which of the following statements is true?

A When the Earth and Sun are in this position, it is winter in the Northern Hemisphere.

B When the Earth and Sun are in this position, it is summer in the Northern Hemisphere.

C When the Earth and Sun are in this position, it is spring in the Northern Hemisphere.

D When the Earth and Sun are in this position, it is autumn in the Northern Hemisphere.

Look at the image. The southern hemisphere is facing the sun. What does that mean? It means it receives

more direct sun light. Therefore it is winter in the Northern Hemisphere. Letter A

Sun

Rays

Nebulae — A cloud of gas and dust in outer space, visible in the night sky as luminous patches or areas of darkness.

Galaxy — A system of millions of stars, along with gas and dust that is held together by gravitational attraction.

Star — A self-luminous celestial body consisting of gases held together by its own gravity(our sun is just a star that is VERY close compared to other stars).

Hertzsprung-Russell Diagrams (H-R) — a scatter graph of stars showing the relationshipbetween the stars’ brightness, classification and temperature.

Our sun is a medium-sized star that is found in the Main Sequence section of the H-R diagram. Our sun is found near the edge of a disc-shaped galaxy, the Milky Way.

Our Solar System contains the sun, its planets and everything else that revolves around it.

Electromagnetic Spectrum – aka EMS, all the differenttypes of electromagnetic radiation; light and radio waves, infrared and ultraviolet light, microwaves,x-rays and gamma rays

Speed of light — All waves travel at the same speed, 300,000 km/s.

Discoveries: Study of light waves (using other types of EM radiation) has allowed us a more detailed study of space such as the composition of stars, planets that may be revolving around them, and distances in space. Radio waves – have provided evidence for the existence of pulsars, cosmic background radiation is evidence for Big Bang theory.

Space is so vast that distances are measured in light years (distance light travels in one year).A light year is about 10 trillion kilometers.

TEK 8.9(B) The student is expected to relate plate tectonics to the formation of crustal features

Divergent — move apart. The crustal feature observed is mid-ocean ridges from sea floor spreading, and rift valleys when on land.

Convergent — move together. May occur with subduction (one plate forced beneath another, causing melting in the Asthenosphere). The features observed are in ocean trenches, island arcs, volcanic ranges, mountains.

Transform — slide past each other. This is observed along fault lines such as in California and earthquakes.

Hot spots — Area within a plate where a burst of heat melts the mantle and crust. These are found in the deep ocean floor and may rise enough to form islands. See the picture to the right.

Topographic map — a two dimensionalrepresentation of a 3-D land surface.

Erosional features — erosion occurswhere the forces of nature move soiland rock through water, wind, ice,gravity and the action of plants andbacteria.

SUN

Life Cycle of a Star

Regular mass star: Nebula—>Protostar—>Main sequence—> Red giant—>White dwarf —> Black dwarf

Large Mass Star: Nebula—>Protostar—>Main sequence—> Red Supergiant —> Supernova—> [if large: neutron star, If super-large: black hole]

Weathering: breaking rock down into smaller pieces(can be chemical or physical)

Erosion: moving small pieces of rock to a differentlocation using wind, water, or gravity

Deposition: depositing (dropping) eroded andweathered rocks into a new place

Runoff: surface water that is not absorbed into theground, eventually feed streams/rivers and reaches the ocean.

TEK 8.9(C) The student is expected to interpret topographic maps and satellite views to identify land and erosional features and predict how these features may be reshaped by weathering.

Category 3 continued…. TEK 8.8 (A) The student is expected to describe components of the universe, including stars, nebulae,

and galaxies and use models such as Hertzsprung-Russell diagrams for classification, (B) recognize that the Sun is a medium-sized star neat the edge of a disc-shaped galaxy of stars that are many thousands of times closer to Earth than any other star.

The Sun provides most of the energy on Earth. It heats oceans, land and atmosphere….but theEarth is heated unevenly

Radiation — energy transfer through waves or rays (radiant energy). 35% isradiated back to space, 65% is absorbed

Conduction — energy transfer through direct contact of molecules of matter. Heat movesfrom higher temperature objects to lower temperature objects

Convection — energy transfer by movement of matter. Due to variations in temp/densityof the substance...Substance cools, it gets more dense and sinks. Substance warms, getsless dense and rises

Convection currents — currents in a substance are caused by hot material rising and cold material sinking; occurs in the atmosphere, oceans, and even Earth’s crust (in the asthenosphere)

Ocean currents — massive currents of water which help to equalize the global temperature of our planet. Currents in the oceans moveenergy from the equator to the poles

Gulf stream — a large ocean current that transports warm water from the Gulf of Mexico to England and N Europe

TEK 8.10 (B) identify how global patterns of atmospheric movement influence local weather using weather maps that show high and low pressures and fronts;

Jet stream — a high-level air current that pushes weather from west to east inNorth America

High pressure —an area where air is sinking, stable weather

Low pressure — and area where air is rising, unstable weather

Front — the area where air masses meet, often bring temperature changes, rainand other weather; cold, warm, occluded (3 air masses), stationary (notmoving)

Air mass — distinct region of air that has same temperature and pressure

Hurricanes — massive, spinning collections of thunderstorms; form over warm waters of Atlantic and Pacific around the Equator; Atlantic storms are formed off the coast of Africa and often hit the SE and E US

TEK 8.10 (C) identify the role of the oceans in the formation of weather systems such as hurricanes.

Category 3 continued…. TEK 8.10 The student knows that climatic interactions exist among Earth, ocean, and weather

systems. The student is expected to: (A) recognize that the Sun provides the energy that drives convection within the atmosphere and oceans, producing winds and ocean currents;

Your Turn—The picture to the left displays the moon orbiting the Earth. An observer is at point X.

How much of the moon is illuminated?

A The moon will reflect the maximum light from the sun.

B The moon will not reflect any sunlight at all.

C The moon will only have a small crescent lit.

D The moon will have a large amount of reflected light from the sun.At position X the moon will appear as a waxing gibbous and will be mostly light. If the maximum were lit, then it is a full moon. Answer D

X

April 27 When standing at position Y, on which date will the 1st quarter moon be seen?

When standing at position Y, on which date will the moon be a waning crescent? May 16

Y

Warm Front-warmer weather-mild rain

Cold Front-violent-cooler

Occluded Front-maintain

Strengthened by : warm air, warm and deep water, and low pressure systemWeakened by : moving over land, cool air and water, high pressure system, and wind shear.