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Science Study sheet Gr. 8 Ch.3-12

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celilasa's version from 2017-09-25 15:34

Section 1

Question Answer
Lost Energyenergy that has escaped from a system
Waste Energyenergy that has been lost from a system
Transformedchanged from one form to another
Transferred: moved from one place to another
Economic Efficiency (everyday usage)the ability to do something well or achieve a desired output without wasting energy, effort, or materials
Mechanical Efficiency (scientific usage)the percentage of work input that is turned into useful work outpu
Customer Servicehelp provided so that customers can use a physical or social system efficiently
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Section 2

Question Answer
Cellthe basic structural and functional unit of life
Cell Theorythe theory that states that all living things consist of cells, that the cell is the basic structural and functional unit of life, and that all cells come from pre-existing cells
Magnificationthe degree to which the appearance of a specimen is enlarged
Field of viewthe visible area of the specimen seen through the eyepiece of a compound microscope
Organellea small structure found within a cell; performs a specific function in a cellv
Cytoplasmthe watery substance in a cell in which the organelles are suspended; also used for transport and chemical reactions
Nucleusthe control center in a cell; stores the genetic information that directs all of the cell’s functions
Chromosomesrod-like structures in the nucleus of a cell: contain the genetic information of a cell
Vacuole a membrane-surrounded storage compartment in a cell; stores food, water, and other materials
Cell Wall a structure surrounding plant cells that protects and supports the cell; made of cellulose
Chloroplast site of photosynthesis; chloroplasts in a plant cell absorb sunlight, carbon dioxide, and water to make food
Flagellatail-like structures that propel cells through their environment
Ciliahair-like projections that help propel the cell or move the substances surrounding the cell
Electron Microscopea microscope that uses beams of electrons instead of beams of light; has more magnifying power than a compound light microscope
Unicellularan organism that only contains one cell
Multicellularan organism that contains two or more cells
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Section 3

Question Answer
Selectively Permeable Membranea membrane that allows only certain substances to pass through it
Diffusionthe movement of particles from an area of higher concentration to an area of lower concentration
Concentration gradient a difference in concentration of a substance between two areas
Osmosisthe diffusion of water across a selectively permeable membrane from an area of higher water concentration (or low solute concentration) to an area of lower water concentration (or high solute concentration)
Turgor Pressurethe outward pressure that is exerted on a plant cell wall by the cell contents when water is taken in by osmosis
Endocytosisthe process by which a cell moves large amounts of material, or non-dissolved particles, into its cytoplasm from the outside environment
Phagocytosisa type of endocytosis in which a cell uses pseudopods to move non-dissolved solid particles into its cytoplasm from the outside environment
Exocytosisthe process by which large amounts of material, or large non-dissolved particles, are moved from a cell’s cytoplasm to the outside environment
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Section 4

Question Answer
Organisma living system with parts that work together to carry out the processes of life
Unicellular Organism an organism made up of only one cell
Multicellular Organisman organism that is made up of more than one cell
Vertebratean animal with a backbone
Invertebrate an animal without a backbone
Fungi organisms that usually obtain nutrients from dead or decaying matter and cannot carry out photosynthesis; nutrients are usually absorbed
Protistan organism that is neither plant nor animal, but shares many of the same characteristics of both; usually unicellular, but can be multicellular
Bacteriathe most basic of all unicellular organisms; lacks a nucleus
Movement a change in the shape or figure of all or part of an organism; a characteristic of all living things
Locomotionmovement that takes an object from one place in its environment to another; a characteristic of animals, animal-like protists, and some bacteria, but not plants or fungi
Cellular Differentiationthe process by which a cell becomes specialized to perform a specific function
Tissuea group of differentiated cells that work together to perform a specific function
Organtwo or more tissues that work together to perform one or more functions
Organ Systema group of organs that work together to perform related functions
Xylem Vessels a system of tubes in a plant that transports water and minerals from the roots to the shoots and leaves
Phloem Vesselsa system of tubes in a plant that transports nutrients (such as dissolved sugars) from the leaves to the rest of a plant
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Section 5

Question Answer
FluidsMaterials that have no fixed shape and are free to flow, such as liquids and gases
Particle Theory of Mattera theory that explains what matter is made of and how it behaves.
Laminar Flow A smooth pattern of flow.
Turbulent Flow An irregular, mixing flow pattern.
EddyAn area of slower-moving fluid that occurs behind an obstacle
Streamlined: A smooth shape designed to decrease resistance to fluid flow.
Flow RateA measure of how quickly fluids move; measured in a volume per unit time
ViscosityA measure of how easily a fluid’s particles are able to slide past one another.
CohesionA measure of how strongly the particles of a fluid attract to each other.
Surface Tension The strong attraction among the particles that form the surface of a liquid.
AdhesionThe attraction between the particles of on substance and the particles of another substance.
Fluid Mechanics The study of fluids and how they behave when at rest and when moving.
Fluid DynamicsA part of the study of fluid mechanics concerned with how fluids move.
AerodynamicsA part of fluid dynamics concerned with how gasses move.
HydrodynamicsA part of fluid dynamics with how liquids move.
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Section 6

Question Answer
Volumethe amount of space an object or substance takes up.
Weight the force of gravity acting on an object
Massthe amount of matter that makes up an object or substance
Displaceto take the place of
Densitya measure of the mass per unit volume of a substance
Characteristic property a property that makes a particular substance distinct from others
Buoyancy: the upward supportive force on an object in a fluid
Swim bladdera controllable, balloon-like chamber that allows fish to alter their buoyancy
Ballast tankscompartments in a ship or submarine that take in water to keep the ship stable or help a submarine dive below the surface
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Section 7

Question Answer
Compressto pack closely together; squeeze
Compressibilitythe ability to be squeezed into a smaller volume
Pneumatic systema system that uses gases under pressure
Hydraulic system a system that uses liquids under pressure
Pressure (scientific definition) the force per unit area
Atmospheric pressure the force the atmosphere exerts on a unit of surface area
Pascal’s Lawstates that a force applied to a fluid is distributed equally through all parts of the fluid
Valvea mechanism that controls the flow of fluid in a pipe or tube
Internal combustion enginea device that provides power by burning fuel within its cylinders
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Section 8

Question Answer
What do physical systems and social systems have in common? How are they different?Both physical and social systems are made of parts that function together to perform a specific task. They can be natural our human made. The parts that make up a social system or organisms, but the parts of the fiscal system are no organisms.
Why are “input” and “output” good words to use when discussing systems?Inputs of the system are things that go into the system to make it work. I’ll puts are things that are produced by, or come out of, the system. Using these words helped as accurately describe systems.
In your own words, define “systems thinking.” System thinking is analyzing a system to figure out how it affects people and things around it.
Describe the relationship between side effects and systems thinking.Systems thinking can help people understand the system and possibly reduce side effects.
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Section 9

Question Answer
Describe the relationship between input force, output force, and load force.Input force is the effort force applied to the leaver; the output force is the force that the lever applies to the load; the load force is the force that the input force has to overcome in order to cause movement.
State two components common to all forces. How are these indicated in a diagram?All forces have magnitude (strength) and a direction. In a diagram, the force is indicated by an arrow. The direction, in which the arrow is pointing, indicates the direction of force, and the length or thickness of the arrow indicates magnitude.
What is the meaning of “mechanical advantage”?Mechanical advantage (MA): the ratio of output force to input force for a given machine
If an output force is five times larger than an input force, what is the mechanical advantage? It would be a ratio of 5:1
The mechanical advantage of a class 3 lever will always be less than 1. Explain why.A greater input force is required then output force
If there is no mechanical advantage to class 3 levers, why are they considered useful? Class 3 levers increase the output distance and speed.
What parts of a pulley system will cause the actual mechanical advantage to be less than the ideal mechanical advantage? Friction in the wheel, groove and strings, as well as the plastic on the metal.
Imagine putting yourself in a push-up position and staying there. Assume that neither the floor nor your body moves. You will use a lot of energy but not accomplish any work. How can energy be consumed when no work is done? In order for work to be done, you have to go a certain distance with an amount of force. This position is only allowing force to be executed, but not any distance, so therefore no work as been accomplished.
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Section 10

Question Answer
In your own words, define “energy.”Energy is what makes able to do what we do.
Since energy cannot be destroyed, what do we mean when we say that energy is lost from a system?Not all energy, put into a system, is converted into useful work. It is sometimes transferred into another source.
What is the most common way that energy is lost in mechanical systems?In mechanical systems, energy is most commonly lost as heat due to friction between parts of a system.
What does friction have to do with energy losses?Friction converts some energy, put into the system, to heat. This generally cannot be used to accomplish work.
What do we do to reduce the negative effects of friction in systems?We add lubricants on system parts, which allow the parts to move more efficiently and effortlessly, reducing the amount of friction.
Explain Efficiency in your own words. Efficiency means accomplishing an amount of work while minimizing the resources used to do it.
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