Science+Vocabulary+for+6th+Grade


 * __ 6th Grade Science Vocabulary __**


 * __ Variables __**
 * 1) 1. Anything that can be changed in an investigation that might affect the outcome is called a **variable.**
 * 2) 2. It is an important feature of a good investigation to repeat a process in order to verify results. Each time you repeat it is called a **trial**. (Should have minimum of 3).
 * 3) 3. An experiment or investigation in which one variable is changed and the outcome is compared to a standard is a **controlled experiment or controlled investigation.**
 * 4) 4. A well designed investigation should follow the **scientific method: Question, Hypothesis,** **Materials, Procedure, Variables, Results, & Conclusion**
 * 5) 5. ** Question: ** what is the question the investigation is trying to answer
 * 6) 6. ** Hypothesis: ** stated in the “if”, “then”, “because” format.
 * 7) 7. ** Variables: ** a list of all controlled variables, independent and dependent variables.
 * 8) 8. ** Results: ** the data presented in an organized fashion (charts, graphs, etc.)
 * 9) 9. ** Conclusion: ** an interpretation of the results should refer back to the hypothesis.
 * 10) 10. ** Two- coordinate graphs should ** have the following components: an appropriate **title-**appropriate **intervals** for numbering axes-appropriate **labels** for the axes-the **independent** variable on the horizontal or “x” axis-the **dependent** variable on the vertical or “y” axis
 * 11) 11. The relationship between where one variable increases, the other decreases is an **inverse relationship**.
 * 12) 12. In a **direct** relationship both variables either increase or decrease.
 * 13) 13. The relationship between the length of a pendulum and the number of swings in a given amount of time is **exponential** as evidenced by the curve on the graph.

Part I 14. ** Temperature ** is a measure of the average amount of particle movement (kinetic energy) in a substance. 15. ** Celsius ** is the metric unit of measure for temperature. 16. ** Fahrenheit ** is the unit used to measure temperature in the United States. 17. ** Heat ** is the total amount of particle movement in a substance (kinetic energy). 18. When heat energy moves from a warmer area to a cooler one until both areas reach the same temperature is called ** Thermal Equilibrium ** 19. ** Conduction ** is the transfer of heat between two materials that are touching 20. ** Convection ** is the transfer of heat through currents within a fluid (liquid or gas). Cool, dense molecules sink while warm, less dense molecules rise creating a current.21. ** Radiation ** the transfer of heat through space. 22. ** Conductor ** a material that transfers heat well. 23. ** Insulator ** a material that does not transfer heat well. 24.Different materials absorb and release heat at different rates called **specific heat**. 25.A **Heat Sink** is a material that has the ability to hold heat well and a high specific heat.
 * __ Heat and Earth as a changing system __**

Part II 26.The Earth is divided into 4 main layers: crust, mantle, outer core, inner core. 27.The **crust** is the solid, outer most layer of the Earth. It has the least amount of heat and pressure. It ranges from 5-40 km thick. 28.The **mantle** is the solid/liquid layer beneath the crust. It has more heat and pressure than the crust. It is approximately 2,900 km thick 29.The **outer core** is the liquid layer beneath the mantle. It has more heat and pressure than the mantle. It is approximately 2,200 km thick. 30.The **inner core** is the solid layer beneath the outer core that has the most heat and pressure. It is approximately 1,228 km in diameter. 32.The continents of today were once joined into a single landmass that he called **Pangaea** 33.The following pieces of evidence support the theory of continental drift: The current continents seem to fit together like pieces of a puzzle-The fossils of the same organism are found on separate continents-Landforms such as mountain ranges seem to match each other in terms of age and location.-The age of rock layers on separate continents match each other. 34. ** Plate tectonics ** are the theory that pieces of the Earth’s crust are in constant motion. 35. The crust and upper mantle are divided into sections called ** plates (crustal plates) **. 36. ** Convection currents ** are the movement of a liquid caused by differences in temperature/ density of the liquid. The constant motion of these plates is caused by convection currents within the mantle. 37. ** Divergent boundaries ** occur where two plates move away from each other. This boundary causes ocean rifts, volcanic eruptions, earthquakes and sea floor spreading. 38. ** Sea floor spreading ** is the process by which molten material adds oceanic crust to the ocean floor. It is a major piece of evidence that supports the theory of plate tectonics. 39. ** Convergent boundaries ** occur where two plates move towards each other. This boundary can cause earthquakes and mountain building. 40. ** Subduction ** can occur if one of the plates goes over top the other plate, pushing the first plate into the mantle. This can cause trenches, volcanoes and earthquakes. 41. ** Transform fault boundaries ** occur where two plates move past each other either in different directions or in the same direction but at different rates. This boundary causes earthquakes and faults. 42. ** Mineral ** is a naturally formed, inorganic solid with a crystalline structure. 43.The **rock cycle** is a series of processes that slowly change rocks from one kind of rock to another. Rocks are made from minerals 44. ** Sedimentary rocks ** are composed of particles from other rocks or the remains of plants and animals and are formed through weathering, compaction and cementation and are usually found near natural bodies of water. 45. ** Weathering ** is the chemical and physical processes that break down rock at the Earth’s surface. 46.Chemical weathering – acid rain, oxidation of metals in rocks 47.Physical weathering – wind, ice, water. Ex: Grand Canyon formed by water moving through rock. 48. ** Erosion ** is the movement of weathered materials from where they formed to a new location and can be caused by running water, glaciers, wind or gravity. 49. ** Sediments ** are Earth’s materials deposited by erosion. 50. ** Compaction ** is a process by which sediments are pressed together under their own weight and results in the formation of sedimentary rock. 52. ** Igneous rock ** forms from the cooling of molten rock at or below the Earth’s surface. 53. ** Metamorphic rock ** forms from an existing rock that is changed by heat, pressure or both. 54.A **fossil** is a trace of an organism that has been preserved and is only found in sedimentary rock. 55.The following are processes by which fossils are formed: **mold and cast, mold, imprint, petrification, preservation.** 56.A fossil is formed when an organism buried in sediment dissolves, leaving an empty space called a **mold**. 57.If minerals seep into the mold and harden to form the copy of the organism’s shape, a **cast** is formed. 58.If minerals do not seep into the mold, an **imprint** fossil is formed. 59. ** Petrification fossils ** are formed by minerals gradually replacing organic material of the organism. 60. ** Preservation fossils ** are formed when an organism is preserved in a substance such as amber, ice, and tar. 62.The deeper a fossil is found in undisturbed rock layers, the older the fossil is. The sequence of fossils found in rock layers can help scientists construct the **geologic time scale** (a record of the sequence in which organisms appeared and disappeared). 63. ** Evolution ** (a gradual process in which species change over time) accounts for the diversity of species. The closer to the surface a fossil is found, the more likely it is to be younger and therefore to resemble an existing species. 64.Some fossils found in the top layers of sedimentary rock are older than those found beneath in lower layers. This can be caused by folding, breaking, uplift, faulting, or tilting of the crust.
 * 1) 31. The theory of **Continental drift** states that continents slowly move across the Earth’s surface.
 * 1) 51. ** Cementation ** is a process that binds sediments tightly to form sedimentary rock. In this process, layers of sediment accumulate, water is squeezed out, mineral deposits that were dissolved in the water remain and crystallize and then bind the sediments together.
 * 1) 61. The characteristics of a fossilized organism can be used to predict the environmental and climate conditions present when the organism was alive.

Part I 65.97% of all water on the Earth is salt water. 66.3% of all water on Earth is fresh water. This 3% can be separated into 2% ice (glaciers) and 1% liquid, thus we have a very limited supply of usable fresh water. 67.The hydrologic cycle is the natural process through which water is recycled. 68.The hydrologic cycle includes **runoff**, **surface water, groundwater**, **precipitation**, **evaporation**, **condensation, filtration, and transpiration.** 69.Evaporation helps to purify water. 70.Briefly review that **permeability** is a characteristic of rock and soil that allows water to easily pass through them. The number and size of the pores in a substance determines the substance’s permeability. 72.An **aquifer** is a permeable layer of rock or soil that allows water to move in or out freely. Wells drilled into aquifers are the source of water for many people. 73.The **water** **table** is the top level of groundwater. This can fluctuate based on the amount of precipitation and water usage. 74.As water seeps into the ground, permeable rock and soil can often act as a filter for pollutants. Part II 75.Scientists have divided the **atmosphere** into layers based on certain characteristics. The 5 layers of the atmosphere include the troposphere, stratosphere, mesosphere, thermosphere, exosphere 76.Weather takes place in the layer closest to the earth (**troposphere**). 77.The **Ozone layer** protects living things from harmful radiation coming from the Sun. 78.In the atmosphere, **density** decreases as the **altitude** increases. 79.Because air has mass, it exerts pressure. This is called **air pressure**. 80.Air pressure is measured using a **barometer**. Normal air pressure at sea level is 14.7lbs/in2. 82.An **anemometer** measures wind speed. 83. ** Relative ** **humidity** is the amount of water vapor the air contains compared to the maximum amount it could hold at a particular temperature. 84.Relative humidity is measured with a sling **psychrometer** and is expressed as a percent. 85.An **air mass** is a large body of air with similar **temperature**, **humidity**, and **air** **pressure**. 86.Air masses have different characteristics based on the region over which they are formed. They can be warm or cold, wet or dry, and have varying air pressures and densities. 87.The amount of water vapor in an air mass is its **humidity** 88. ** Evaporation ** is a cooling process. As a liquid evaporates (changes from a liquid to a gas) it gains heat energy. The liquid takes the heat energy from its surroundings. The surroundings are cooled because they have given up energy. 89.Air that has a relative humidity of 100% is said to be **saturated**. If the air is saturated, it is holding the maximum amount of water it can hold at that temperature. No additional evaporation can take place. 90.Air masses with different characteristics do not usually mix. When two different air masses meet, a boundary forms between them. This boundary is called a **front**. 92.A **warm front** occurs as a warm air mass moves towards a cold air mass. The warm air mass is less dense, so it slowly moves over the denser cold air mass. The warm air mass gradually replaces the cold air mass, resulting in lower air pressure, precipitation or overcast skies. It is followed by clear warm weather. It is the movement of air masses that circulates water throughout the atmosphere. 93.A **pressure system** is a region/area of the Earth’s atmosphere where air pressure is unusually high or low. 94. ** High-pressure systems ** are associated with clear, fair weather. As cool, dense air sinks towards the Earth’s surface, it becomes warmer and moisture in the air evaporates causing less clouds and precipitation. 95. ** Low-pressure systems ** are associated with bad weather and storms. As warm, low-density air rises, it cools. Water vapor condenses and relative humidity increases causing clouds to form. Rain, snow, sleet, or hail may follow. 96. ** Thunderstorms ** are heavy rainstorms with thunder and lightening that are formed by the rapid upward movement of warm, moist air (low pressure). Thunderstorms can occur in warm, moist air masses, but often occur at cold fronts as moist air is forced upward, and water vapor cools and condenses forming cumulus clouds. Large falling water droplets create strong winds. 97. ** Tornadoes ** are violent, funnel-shaped storms with whirling winds that travel over land. Tornadoes form from severe thunderstorms and also involve the rapid upward movement of warm, moist air into clouds. High winds in the cloud and cool downdrafts can cause the spinning motion/rotation of a tornado. 98. ** Hurricanes ** are very large, swirling, low-pressure systems that form over tropical oceans. Winds blow at least 120 km/hour. Warm air rises creating a lower pressure below.
 * __ Hydrologic Cycle, Atmosphere & Weather __**
 * 1) 71. Groundwater is water that is in the **pores** of permeable rock and soil.
 * 1) 81. A **thermometer** measures temperature.
 * 1) 91. A **cold front** occurs as a cold air mass moves towards a warm air mass. The cold air mass is **denser** and pushes up the less dense, warm air mass resulting in higher air pressure. This results in violent storms followed by cooler weather.

99.Surrounding higher-pressure air swirls in to take its place. Air continues to be drawn in, heated, and it rises. A calm area of very low pressure, called the eye, is created in the center.
 * 1) 100. ** Climate ** is the average temperature and precipitation of a region.
 * 2) 101. Factors that effect climate include: bodies of water, currents (ocean, wind), surface material (water, sand, grass, etc.), **latitude**, **elevation**, **atmosphere** (clouds, dust, ash, etc.), man-made structures (EX: large amounts of concrete in a city).
 * 3) 102. Large bodies of water can cause milder temperatures along the coastline.
 * 4) 103. Volcanic Eruptions spew smoke and ash into the air that can block sunlight causing lower temperatures.


 * __ Astronomy __**

111.The **period of rotation** is the time it takes a celestial body to spin once on its axis. 127.The planets in order from the sun outward are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and the dwarf planet Pluto.
 * 1) 104. The axis of the Earth is tilted at 23.5˚.
 * 2) 105. The axis is tilted in the same direction (towards the North Star, also called Polaris) at all times.
 * 3) 106. The tilt of the Earth’s axis causes changes in the angle of the sun’s rays in the sky during the year. This causes uneven heating of the Earth’s surface, resulting in seasons.
 * 4) 107. The sun’s most direct rays fall between the Tropic of Cancer (23.5˚ north latitude) and the Tropic of Capricorn (23.5˚ south latitude). Areas north of the Tropic of Cancer and areas south of the Tropic of Capricorn never receive direct rays of the sun.
 * 5) 108. Maryland has four distinct seasons that are caused by the tilt of the Earth.
 * 6) 109. The **period of revolution** is the time it takes a celestial body to orbit once around another object. A planet’s period of revolution depends on its distance from the sun.
 * 7) 110. The revolution of a planet determines its **solar year**.
 * 1) 112. The rotation of a planet determines the length of its **solar day.**
 * 2) 113. The moon’s surface is illuminated as sunlight is reflected off the surface.
 * 3) 114. Moon phases are caused by the moon’s revolution around the Earth and the relative positions of the sun, the moon, and the Earth.
 * 4) 115. A **solar eclipse** occurs when Earth passes into the moon’s shadow.
 * 5) 116. A **lunar eclipse** occurs when the moon passes into the Earth’s shadow.
 * 6) 117. A **tide** is the regular rise and fall of Earth’s oceans.
 * 7) 118. Tides on Earth are caused by the gravitational forces acting between the sun, the moon, and the Earth. On a daily basis, the tides exhibit a predictable pattern.
 * 8) 119. ** Spring tides ** occur during the full and new moons and are characterized by the greatest difference between high and low tides.
 * 9) 120. ** Neap tides ** occur during the first and third quarter moons and are characterized by the least difference between high and low tides.
 * 10) 121. A **galaxy** is a giant celestial structure that contains hundreds of billions of stars.
 * 11) 122. The **universe** is all of space and everything in it. It is estimated to be over 10 billion years old and contains billions and billions of galaxies.
 * 12) 123. ** Spiral galaxies ** have flattened arms of young stars, gas, and dust that spiral around a nucleus of bright stars.
 * 13) 124. ** Elliptical galaxies ** have shapes that vary from nearly spherical to football-shaped. They contain mostly older, dimmer stars.
 * 14) 125. ** Irregular galaxies ** do not have a particular shape and tend to be smaller and fainter than other types of galaxies.
 * 15) 126. Our solar system is a very small part of the **Milky Way Galaxy**, a spiral galaxy.
 * 1) 128. ** Gravity ** and **inertia** are responsible for the pattern of motion of celestial objects.