Science final grade 8 study guide!

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Science

Science final study guide

93 Terms

1

natural light source

light made naturally

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Artificial light source

Made by man

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3

Incandescent

Produces light from high heat temperatures

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4

Fluorescent

Electric light formed in tube shape and light being produced on inside by mercury Vapor and phosphor coating

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5

chemiluminescence

Light coming from a chemical reaction

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6

Bioluminescence

A light produced by nature; natural

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7

Transparent

When an object lets all light through

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8

Translucent

When light partially passes through

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9

Opaque

  • When no light passes through

  • Light is absorbed

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10

Incident ray

The light ray hitting the reflective surface

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11

Reflected ray

The light ray being reflected of the reflective surface

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12

The normal

Imaginary line of the middle

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13

Plane mirror

Flat reflective surface

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14

Light form

  • energy

  • electromagnetic radiation

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15

light particle

photon

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16

visible light spectrum

on the electromagnetic spectrum

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17

longer wavelength vs shorter wavelength

  • longer wavelength - less energy

  • shorter wavelength - more energy

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18

photoelectric effect

where you see light as a particle

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19

double slit experiment

shows light is a wave

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20

Reflection

  • When a light ray bounces off an object

  • Law of reflection - reflection off a smooth surface must have an angle of a reflection equal to the angle of incidence

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21

Refraction

  • when light changes direction when passing though an object

  • When light hits the substance it slows down, drifts, then when out of the substance, it changes direction

  • Denser material → bends towards the normal

  • Less dense material → further from the normal

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22

Light transmission

  • light passes through all the way

  • Ex: a window

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23

Light absorption

  • when light doesn’t pass through

  • Ex: a desk

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24

Concave mirror

  • Concave mirror - reflects inward and upside down

  • Ex: telescope

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25

Concave lens

  • reflects outward

  • Used for glasses lens for people with myopia; nearsightedness

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Convex mirror

  • reflects outward and image appears smaller

  • Ex: security mirrors

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Convex lens

  • Reflects inward towards the focal point

  • Used for people with hyperopia; farsightedness

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28

parts of the eye

  • Cornea

  • Retina

  • Lens

  • Optic nerve

  • Cones

  • Rods

  • Aqueous Humor

  • Pupil

  • Iris

  • Sclera

  • Ciliary muscle

  • Virtuous Humor

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29

Real image vs virtual image

  • Real image - when rays converge

  • Virtual image - when rays diverge

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30

examples of vision enhancing technologies

  • laser eye surgery

  • Glasses

  • VR

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31

Class 1, 2, 3 lever

  • C1 - fulcrum in middle

  • C2 - fulcrum on left

  • C3 - fulcrum on right

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32

Effort force

  • Force applied to machine

  • the force we apply to move the object (input force)

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Load force

the object that is trying to be moved

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effort arm

Where effort is applied (the input force)

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35

Load arm

The arm that carries the load

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36

Mechanical advantage (MA)

Ratio of input force to output force

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37

Inclined plane

A slope, mainly to push objects down

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38

Work

The amount of work being done to an object, what force has caused it to do

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39

Work input

Amount of energy put into the machine

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40

Work output

The work that was done by a machine

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41

Wheel and axle

A wheel that spins around an axle

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42

Gear

Turn force to motion

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43

Gear train

2 or more gears working together

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44

Chain and sprocket

Chain that hooks into the teeth of the gears and moves them

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Driven gear vs driving gear

  • Driven - the front gear

  • Driving - the last gear

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Speed ratio

  • ratio of output speed to input speed

  • Greater than one - driven gear slower than driving gear, increasing torque (rotation) but reducing speed

  • Equal to one - spins at equal speeds

  • Less than one - gears turn faster, less torque more speed

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Fixed pulley

Rope attached to fixed point

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48

Movable pulley

Free to move up or down

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49

Compound pulley

Fixed and movable pulley

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50

Potential Energy

The energy that is stored

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51

Kinetic energy

Energy made by motion

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52

Energy transmission

same type of energy moves from one object to another

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53

Energy conversion

energy switches to different type in same object

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54

Efficiency

  • how much energy from machine was transferred to load

  • stated as percent

  • higher efficiency, better at transferring energy

  • never a completely efficient machine because there is a loss of energy

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55

Friction

Force that stops motion when in contact with two surfaces

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Complex machine

Made of two or more simple machines

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subsystems

System that are apart of a larger system

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Greater than 1

Force advantage

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59

Less than 1

Speed advantage

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60

Equal to one

No advantage of moved direction to effort

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Work formula

  • W = F x D

  • Measured in joules

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62

Ramp and lifting straight up equal work

More distance is needed while using a ramp

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63

Water quality

Condition and characteristics of water

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64

Ground water

Water that is stored underground

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65

Salinity

The amount of salt found in the water

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Erosion

Weather displaces sediments

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67

Ocean basins

The largest depression in earth

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68

glaciation

land is covered by glaciers

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69

El Nino and la nina

El Nino - when ocean temperatures rise

La Niña - ocean temperatures cooling

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70

Phosphates

Chemical compound that contains phosphorus

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71

water distribution

drinking water that comes from plant goes to taps

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72

potable

water that is safe to consume

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73

osmosis

low concentration to a high concentration

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74

deposition

laying down sediments through weather

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75

sea wall

wall to protect shore from erosion

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currents

movement of seawater by gravity, winds, and water density

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turbidity

water quality of being cloudy, thick, or opaque

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evaporation

when liquid gets turned into vapor; liquid to gas

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79

reverse osmosis

forcing salty or brackish water through a semipermeable membrane by applying pressure, leaving solutes on one side of the membrane

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80

flow rate

how fast a liquid flows

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81

gulf stream

  • ocean water has more thermal energy then atmosphere

  • thermal energy transfers to air

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82

sediment

solid material that is moved and moved to new location

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dissolved oxygen

oxygen that is in water

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84

upwelling

when cold nutrient water is pushed to the top of the ocean

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85

Ocean formation

  • coastline

  • Continental shelf

  • Continental slope

  • Continental slide

  • Abyssal plain

  • Oceanic trench

  • Volcanic island

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86

Two main factors that impact ocean currents

  • salinity

  • Temperature

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87

Increased temperature and salinity

  • increased temperature expands water slightly, making it dense and causes upwelling to happen

  • Increased salinity increases density by the amount of salt dissolved in water

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88

Currents

Move heat, nutrients, and oxygen around ocean

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89

Waves and tides

  • surface waves caused by wind

  • Visible flow of energy

  • Tides because of moons gravitational pull

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90

Glaciers

  • erratics proves glaciers move over time

  • Form in a cirque

  • Form terminal or lateral moraines

  • Creation of wide valleys (U shaped)

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91

Stream and river characteristics

  • intermediate, small, and fine types of sediments

  • Erosion can cause rivers to form into a new shape

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92

Fresh water solutions

  • distillation - salt water turned into fresh water

  • Reverse osmosis- forcing salty or brackish water through semipermeable membrane by applying pressure, leaving solutes on one side, and the other has fresh water

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93

Environmental challenges for marine organisms

  • temperature

  • Water movement

  • Water pressure

  • Light

  • Salinity

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