General Science Grade 7 Unit 4 Reviewer


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General Science Grade 7 Unit 4 Reviewer

  1. 1. GENERAL SCIENCE REVIEWER- 4TH QUARTER1. LATITUDE-Lines of Latitude run horizontally  Latitude is measured in degrees.  The Equator is 0 degrees Latitude.  Lines of Latitude locate places North or South of the Equator.  The North Pole is 90 degrees N Latitude, and the South Pole is 90 degrees S Latitude.2. LONGITUDE-Lines of Longitude run vertically. They are also called Meridians.3. The PRIME MERIDIAN is found in Greenwich, England.  The Prime Meridian is 0 degrees Longitude.  Lines of Longitude locate places East or West of the Prime Meridian.  There are 180 degrees of east Longitude, and 180 degrees of west Longitude.4. INTERNATIONAL DATELINE- line where the date changes: an internationally agreed imaginary line running roughly along the 180º meridian of longitude, to the east of which the date is one day earlier than to the west5. TIME ZONES- Time zones are broad strips that measure 15 degrees wide.  Time zones differ from their neighboring time zones by 1 hour.  The world rotates west to east (counterclockwise), time zones to the east are ahead of the those time zones to the west6. EAST INCREASE  Time is forward to all places to the east7. WEST LESS  Time is backward to all places to the west8. AIR PRESSURE- Air is held to the earth by gravity. This strong invisible force pulls the air downward, giving air molecules weight. The weight of the air molecules exerts a force upon the earth and everything on it. The amount of force exerted on a unit surface area (a surface that is one unit in length and one unit in width) is called ATMOSPHERIC PRESSURE OR AIR PRESSURE. The air pressure at any level in the atmosphere can be expressed as the total weight of air above a unit surface area at that level in the atmosphere. Higher in the atmosphere, there are fewer air molecules pressing down from above. Consequently, air pressure always decreases with increasing height above the ground. Because air can be compressed, the density of the air (the mass of the air molecules in a given volume) normally is greatest at the ground and decreases at higher altitudes.9. HIGH PRESSURE AREA/ LOW PRESSURE AREA  Sea-level pressure varies by only a few percent. Large regions in the atmosphere that have higher pressure than the surroundings are called HIGH-PRESSURE AREAS.
  2. 2.  Regions with lower pressure than the surroundings are called LOW-PRESSURE AREAS. Most storms occur in low-pressure areas. Rapidly rising pressure usually indicates that sky is clear, falling pressure usually means a storm is approaching.10. COLD AIR- is denser than WARM AIR; air EXPANDS as it is heated and it becomes LESS DENSE, air CONTRACTS as it cools and it becomes DENSER.11. ISOBARS- Isobars are lines of equal atmospheric pressure drawn on a meteorological map.On a weather map, isobars placed close together indicate that the pressure is high and the wind is strong.12. LAYERS OF THE ATMOSPHERE  TROPOSPHERE-lowest layer of the earths atmosphere and site of all weather on the earth; the air molecules in the bottom of the troposphere is dense because of the weight above it.  THERMOSPHERE-the region of the atmosphere above the mesosphere in which temperature steadily increases with height, beginning at about 85 km/53 mi above the Earths surface; heat cannot be felt though it is very hot because they are only few and very far from each other.13. MERCURY BAROMETER- consists of a glass tube about 840 mm (about 33 in) high, closed at the upper end and open at the lower. When the tube is filled with mercury and the open end placed in a cup full of the same liquid, the level in the tube falls to a height of about 760 mm (about 30 in) above the level in the cup, leaving an almost perfect vacuum at the top of the tube. Variations in atmospheric pressure cause the liquid in the tube to rise or fall by small amounts, rarely below 737 mm (29 in) or above 775 mm (30.5 in) at sea level14. ANEROID BAROMETER-device indicating air pressure: an instrument for indicating atmospheric pressure on a circular dial; A more convenient form of barometer (and one that is almost as accurate) is the aneroid, in which atmospheric pressure bends the elastic top of a partially evacuated drum, actuating a pointer. A suitable aneroid barometer is often used as an altimeter (instrument measuring altitude), because pressure decreases rapidly with increasing altitude (about 25 mm/1 in. of mercury per 305 m/1000 ft at low altitudes).15. ANEMOMETER-(Greek anemos, “wind”; metron, “measure”), an instrument that measures wind speed. The most common kind of anemometer consists of three or four cups attached to short rods that are connected at right angles to a vertical shaft. As the wind blows, it pushes the cups, which turn the shaft. The number of turns per minute is translated into wind speed by a system of gears similar to the speedometer of an automobile.
  3. 3. 16. CORIOLIS EFFECT-deflection relative to Earth: the observed deflection of something such as a missile in flight relative to the surface of Earth, caused by Earths rotation beneath the object. The deflection is to the right in the northern hemisphere and to the left in the southern hemisphere.17. SOUTHWEST MONSOON-In the summer months, they begin to blow from the southwest, absorbing moisture as they cross the Indian Ocean. This warm, moist air creates heavy rains as it rises over the Indian Peninsula and is finally forced up the slopes of the Himalayas;while rain-bearing monsoon winds blow from the southwest during the summer months of April or May to September (the “wet season”) this is known as HANGING HABAGAT in the PHIL. (Phil-July-November)18. NORHT EAST MONSOON-Winds blow from the northeast during the winter months of October to March or April (known as the “dry season,) the cold air from Siberia moves toward the low pressure area in the south china sea but the Coriolis effect turns it to the right; HANGING AMIHAN (Phil-December-February)19. SEA BREEZE- happens at day time; cold air from the sea blows into the land to replace the rising air20. LAND BREEZE- happens at night; cold air from the land blows into the sea to replace the rising air21. ROTATION- spinning of the earth on its axis; 23.5 degrees tilt; causes day and night cycle.22. REVOLUTION- spinning of the earth around the sun as it travels an imaginary path called an orbit;Cause the changes in seasons.23. TIDES-periodic rise and fall of all ocean waters, including those of open sea, gulfs, and bays, resulting from the gravitational attraction of the moon and the sun upon the water and upon the earth itself.
  4. 4. 24. SPRING TIDES- tide at new and full moon: a tide that occurs near the times of the new moon and full moon and has a greater than average range; very high high tide and very low low tides, extreme;sun, moon and earth form a straight line25. NEAP TIDES-lowest high tide: a tide that shows the least range between high and low and occurs twice a month between the first and third quarters of the moon; not very high high tide, not very low low tide, moderate; sun is at the right angle to the moon relative to the earth26. SOLAR ECLIPSE-partial or total obscuring of the sun by the moon, with a resultant shadow cast upon the earth. (Sun-Moon-Earth)27. LUNAR ECLIPSE- partial or total obscuring of the moon by the earths shadow. (Sun-Earth- Moon)28. MOON PHASE-the different angles from which we see the lighted part of the Moons surface.
  5. 5. 29. SEASONS-traditional division of year: a traditional division of the year based on distinctive weather conditions. In temperate regions, there are four seasons, spring, summer, fall, and winter, while in tropical countries there are often only two, a dry season and a rainy season.Because of the tilt of the Earth’s axis, the amount of sunlight falling on the different regions of the earth changes throughout the year.30. SOLSTICE-means“Sun stands still”; longer length of days or longer length of nights. The solstice north of the celestial equator is called the SUMMER SOLSTICE because the Sun is usually at its greatest declination on June 21 or 22 (at the beginning of summer in the Northern Hemisphere); the solstice south of the celestial equator, called the WINTER SOLSTICE, usually occurs on December 21 or 22.31. EQUINOX-equal length of day and night in all parts of the earth32. VERNAL (SPRING)EQUINOX-one of two times of year when the Suns position makes day and night of equal length in all parts of the Earth. The vernal equinox usually occurs on March 20 or 21 and marks the beginning of the spring season in the Northern Hemisphere.33. AUTUMNAL (FALL)EQUINOX- one of two times of year when the Sun’s position makes day and night of nearly equal length in all parts of the Earth. The autumnal equinox, which usually occurs on September 22 or 23, marks the beginning of the fall season in the Northern Hemisphere.