Download Key Points to Review for Science

Key Points to Review for Third Grade Science
Magnets
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Magnets have a North Pole and a South Pole. Opposite poles attract or pull
together.
Like poles( North and North, or South and South )will repel or push apart.
A magnetic compass always points north.
Magnets attract other objects that contain iron.
Magnets have a magnetic field around them.
Magnetic force flows out through the north pole of the magnet and back in the
south pole.
Magnets can be permanent or temporary.
Magnets are used in generators to produce electricity.
Magnets are used in many items used at home and in the work place. They are in
computer, televisions, radios, fans, blender, remote-controls, cars, trains, and
many more things that we use every day.
Loadstone is a natural magnetic rock.
Rocks, Minerals, and Soil
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Minerals are solid objects found in nature that have never been alive.
Rocks are made from a combination of different minerals. All rocks are minerals,
but not all minerals are rocks.
There are three different types of rocks. (sedimentary, igneous, and metamorphic)
Sedimentary rocks are formed form layers, igneous rocks are formed from melted
rock that has cooled and hardened, and metamorphic rocks are formed from
sedimentary or igneous rocks that have been under extreme heat or pressure.
The Earth is made up of the Core, Mantle and Crust.
Minerals are identified by their properties. Scientist use hardness scales, color,
texture, and shape to identify minerals.
Luster is a word that describes the surface shine of a mineral.
Diamonds are the hardest minerals. No other minerals can cut a diamond.
Obsidian is a shiny black mineral that is sometimes called volcanic glass.
Talc is a very soft mineral.
Graphite is a mineral used to make pencils.
Rock is changed into soil through weathering.
Weathering is the wearing away of rock by wind or water.
Erosion is the movement of rock or soil by wind or water. Moving it from one
place to another.
There are different types of soil. ( sandy soil, clay, and topsoil )
Humus is made up of decayed organic matter such as dead plant and animal parts.
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The particles in clay soil are very small and powdery. When they become wet
they stick together and form a very hard surface. Plants do not grow well in clay
soil.
Sandy soil has very large particles, and it does not retain water. It dries out very
fast and plants do not grow well.
Plants grow best in topsoil with humus. It is usually very dark looking soil.
Heat
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Energy that moves particles in matter is called thermal energy.
Movement of thermal energy from one place to another is called heat.
A thermometer is a tool used to measure heat.
Heat moves through space from the Sun to the Earth by radiation.
Heat moves through liquids and gases by convection.
A material such as metal through which thermal energy can move easily is call a
conductor.
A material such as wood through which thermal energy cannot move easily is call
an insulator.
The force between two objects that keeps them from moving freely is friction.
Friction is the force that makes matches work.
What we feel as heat is thermal energy.
Matter with slow moving particles is cool.
Matter with fast moving particles is warm.
Heat always travels from hot to cold.
Energy moves easily through conductors.
Rubbing our hands together makes friction or heat.
To keep thermal energy from moving we use insulators.
Adding thermal energy can change particles in liquid into a gas.
Thermal energy that moves without touching anything is radiation.
You can produce thermal energy by friction, burning, or chemical reactions.
When cold air meets hot air the cold air sinks and the hot air rises.
An insulated beverage container is used to keep hot things hot, and cold things
cold.
Energy from the sun is often called solar energy.
The sun gives us heat energy and light energy.
Burning a candle gives heat and light energy.
Fossils
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Scientists study fossils to learn about the past.
Scientists can learn about extinct plants and animals from studying fossils.
Fossils show what types of food ancient animals ate.
Fossils can be found in rock, amber, tar deposits, and frozen earth.
When archaeologists excavate through layers of rock that contain fossils, the
oldest fossils are found in the deepest layers.
Most fossils are found in sedimentary rock.
The hard parts of organisms help to form fossils.
Habitats of Georgia
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Different regions of Georgia have different types of soil because of the types of
rock formations in that region.
The three Mountain regions have a soil made up mostly of sedimentary rock and
metamorphic rock because millions of years ago this area was underwater, but
during the Ice Age large glaciers pushed the land and the mountain region was
formed. The cave areas in the mountains are formed in sedimentary rock that has
been eaten away by water and acid.
The Piedmont area( foothills of the mountain) has a great deal of granite
outcroppings. The rolling hills of the Piedmont were formed through millions of
years weathering on the Appalachian Mountains. Geologists estimate that
between 5 and 10 miles of vertical rock have been eroded from the Appalachian
Mountains and washed into the sea. Some of this material now forms the
piedmont, coastal plain and barrier islands of Georgia.
Most of the population of Georgia lives in the Piedmont region. Atlanta is in the
Piedmont region.
The Coastal Plains area has a more sandy type soil.
The Coastal Plains were a one point in history underwater. The soil is made up of
sediment that has run off from the Mountain and Piedmont regions.
The swamp/marsh areas are located in the southeastern portion of Georgia.
Georgia’s different regions have different habitats.
Different habitats provide the best conditions for different types of plants and
animals to survive.
Organisms depend upon one another and their environment for survival.
Changes to an organism’s habitat can be either beneficial or harmful to it.
Most of the changes to habitats have been caused by humans.
Nature can also change habitats through climate changes, floods, storms, and
earthquakes.
Human are over-taking the natural habitats of many species of wildlife.