Download 6th Science Semester 2 Review

6th Grade Science Semester 2
Exam Review
Lab Safety
Goggles are always required during experiments using heat, chemicals, and glassware.
Lab Tools/Measurement
Mass- The amount of matter in an object
Volume- The amount of space an object occupies
Density- The amount of matter in a given volume
Another name for the metric system is SI, for international system of units
Metric Ruler- measures length
Triple Beam Balance- measures mass
Graduated Cylinder- measures volume
Spring Scale- measures force
Thermometer- measures temperature
Tongs & Test Tube Holders- used for holding hot objects
Measuring Practice Websites:
Triple Beam Balance:
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=GCH202
Graduated Cylinder:
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=gch302
Finding the volume of an irregular object using water displacement: Measure the volume
of the water in a graduated cylinder. Add the object. Measure the volume of the water
with the object. Subtract the two measurements.
The density of water is 1g/ml.
Objects with a density greater than 1g/ml sink, objects with a density less than 1g/ml
float. If an object’s mass is greater than it’s volume, the object will always sink.
Experimental Design
The scientific method steps in order:
1. State the Problem
2. Gather Information (research)
3. Make a Hypothesis
4. Perform an Experiment
5. Record and Analyze Data
6. Make a Conclusion
Manipulated Variable (Independent Variable)- The factor that is changed purposely during
an experiment. Think “Manipulated is changed by man”. There can be only ONE
manipulated variable in an experiment.
Responding Variable (Dependent Variable)- The factor that responds to the changes
made in the experiment. It is what is measured during the experiment.
Controlled Variable- The factors that stay the same in the experiment. There can be many
controlled variables.
DRY MIX- Stand for “The Dependent/Responding Variable is graphed on the Y axis”.
“The Manipulated/Independent Variable is graphed on the X axis”.
Elements and Compounds
Element- A pure substance made of only one kind of atom.
Compound- A substance made of two or more atoms chemically combined in a set ratio.
How to know the difference between an element and a compound: Each element on the
periodic table is represented with a capital letter (and possibly a lower case letter). For
example: Oxygen- O, Iron- Fe, Helium- He. By counting the number of capital letters in a
chemical formula, you can determine how many different elements are in a substance.
CO2 has two capital letters, so it has two different elements (Carbon and Oxygen), which
makes it a compound.
Physical Properties of Elements
Conductivity- The ability to allow the flow of electricity or heat through an object
Malleability- The ability to be hammered or flattened into shape
Ductility- The ability to string a substance into a wire
Luster- How light reflects off of an object (dull or shiny, metallic or non-metallic)
Observe the periodic table above. Notice that the metals are blue and located on the left
side of the table. The non-metals are red and located on the right side of the table. The
metalloids are yellow and are located on a “zig-zag” line between the metals and
nonmetals. Which element on this periodic table is mis-colored? Why do you think this is
so?
Physical Properties of Metals V/S Nonmetals
Metals are mostly solids that have shiny luster. They are malleable, ductile, and easily
conduct electricity. Nonmetals are usually liquids and gases. When nonmetals are solids,
they are usually brittle (break easily), neither ductile nor malleable, and dull in luster.
Nonmetals are not conductors. Metalloids are found between metals and nonmetals on
the periodic table because they have properties of both metals and nonmetals,
depending on the specific element.
Heat Transfer
ConDuction- The transfer of heat by direct contact. The “D” stands for direct contact.
ConVection- The Transfer of heat through a vapor (liquid, gas). The “V” stand for vapor.
Radiation- The transfer of heat through waves/empty space.
When is heat energy lost? When heat is removed from a substance. Examples are freezing
(liquid to solid), and condensation (gas to liquid).
When is heat energy gained? When heat is added to a substance. Examples are melting
(solid to liquid), creation of steam/vapor (liquid to gas).
Energy
Forms of EnergyGeothermal- Renewable, no pollution
Solar- Renewable, no pollution
Hydropower- Renewable, no pollution
Natural Gas- Non-renewable, causes pollution
Coal- Non-renewable, causes pollution
Petroleum- Non-renewable, causes pollution
(also called oil)
Conservation of Energy: Energy is never created or destroyed, it just transfers from one
substance to another.
Examples of energy transfer (energy converted from one form to another):
Electrical to Thermal- toaster, hair-dryer
Chemical to Mechanical- food in your body giving you energy to move, burning coal to
make a turbine move
Mechanical to Electrical- wind up/crank radio, a moving turbine making electricity
Chemical to Radiant- batteries in a flashlight, burning wood on a campfire
Ways to Conserve Energy (not wasting energy):
Turn off lights when leaving a room, adjusting the thermostat when leaving your house,
replace incandescent light bulbs that give off unwanted heat with fluorescent light bulbs,
unplug phone chargers when not in use (they still use energy without the phone
attached).
Potential Energy- energy that is stored. The greater the height of an object, the more
potential energy it has. A ball dropped from the top of the bleachers will fall longer than
one dropped the middle of the bleachers. It has the greater potential for speed.
Kinetic Energy- energy that is in motion
Machines
Friction- the force that one object exerts on another when two objects rub against each
other; examples include rubbing your hands together to make heat and tires on a road.
Inclined planes are machines such as ramps and stairs. They make work easier by
reducing the force needed to move an object (you don’t have to push as hard). The
object will travel a farther distance when using a ramp because it move up the entire
length of the ramp, instead of straight up if you were lifting the object.
Earth’s Layers
The lithosphere is made of
the crust and upper
mantle. The tectonic
plates that move and
shape our land are made of
the lithosphere.
The asthenosphere is made
of the middle mantle. It is
semi-solid and moves like
syrup. Convection currents
are found in this layer. The
lithosphere floats on top of
the asthenosphere.
Plate Tectonics
Convergent boundary- located where two plates move towards each other. Subduction
zones occur at convergent boundaries. Mountains, trenches, and volcanoes can be found
at these boundaries.
Divergent boundary- located where two plates move away from each other. Mid-ocean
ridges are found along these boundaries.
Transform boundary- located where two plates slide past each other in a side to side
motion. Earthquakes are found at these boundaries.
Review the map to the left.
Make sure you know the
location of the following
plates:
North American Plate
Indo-Australian Plate
Nazca Plate
South American Plate
Eurasian Plate
Antarctic Plate
African Plate
Pacific Plate
Space/Astronomy
Galileo Galilei- credited for inventing the telescope, observed the movements of planets
to prove the heliocentric theory where all the planets in our solar system orbit around the
sun.
Sir Isaac Newton proved that the planets stay in orbit/motion due to the forces of inertia
and gravity. He lived after Galileo and also believed in the heliocentric system.
When planning modern space mission (like the Mars Bound Project), NASA must consider
the cost of the mission, the energy needs, mass of the equipment, and purpose of the
mission (goals).
Planets Facts
Rocky/Terrestrial Planets (Inner Planets) in order:
Mercury- .3 size of Earth
Venus- .9 size of Earth
Earth- 1 Earth (12,756km in diameter)
Mars- .5 size of Earth
Gas Giants (made of Hydrogen and Helium) in order:
Jupiter- 11 Earths
Saturn- 9 Earths
Uranus- 3.6 Earths
Neptune- 4 Earths
Cells
Unicellular- one-celled organisms like bacteria and yeast
Multicellular- more than one cell, flowers, mushrooms, insects
Heterotroph- must eat or obtain food, humans, mushrooms, jellyfish
Autotroph- make their own food using sunlight (photosynthesis), green plants
Prokaryote- organisms that do not have a good nucleus, bacteria
Eukaryote- organisms that have a good membrane bound nucleus that holds the DNA,
animals, oak tree, euglena
The Cell Theory:
1. All organisms are made of cells.
2. All cells are produced by other living cells.
3. The cell is the most basic unit of life.
Four Kingdoms of Eukaryotes
Animal Kingdom- multicellular and heterotrophs
Plant Kingdom- multicellular and autotrophs
Protist Kingdom- unicellular and can be an autotroph or heterotroph
Fungi Kingdom- can be multicellular or unicellular and heterotrophs
Ecosystems
Population- all the organisms that same type (species) in a certain area, a species of ants
Habitat- the place an organism lives gets its needs provided for
Community- all the different types of organisms living in a certain area, ants and squirrels
live in the same community
Biotic factors- all the living things in an ecosystem, trees and birds
Abiotic factors- all the non-living things in an ecosystem, rocks and water
Rock Cycle
Igneous Rock- made from magma (molten rock) that has cooled and hardened. Found
around volcanoes.
Sedimentary Rock- made from compaction (pressing) and cementation (glue) of
sediments. Often found in layers by water and can contain fossils.
Metamorphic Rock- made from extreme heat and pressure. These rocks can have bands
or stripes in them.
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All 3 rock types can be directly changed into each other.
Speed
Speed is calculated by dividing distance by time (distance goes in the calculator first).
If a car travels 180 miles in 3 hours, what is the average speed of the car?