Science 8 Study Guide

1. explain the role of Sputnik in the exploration of space

The first man-made object in space

2. recognize the names of the Presidents who were instrumental in the space race

JFK, Ronald Regan, and Lyndon B. Johnson

Mercury

used to perfect communications and study how space affected astronauts, one manned.

Gemini

was developed to achieve rendezvous, docking, EVA(spacewalk), and held two people.

Apollo

manned by 3 people and is what got us to the moon

Who was the 1st astronaut in space?

Yuri Gagarin

Who was the first US astronaut in space

Alan Shepard

Who was the first man on the moon?

Neil Armstrong

Apollo 1

A fire was set in the cockpit because of frayed wires, a pure O2 environment, and a manual hatch

Apollo 8

1st Apollo mission around the moon

Apollo 11

Landed on the moon

Apollo 13

Safely landed back on Earth after an oxygen tank exploded in orbit

Challenger

frozen o-rings

Columbia

Heating tiles fell off

explain why a manned mission to Mars will be difficult

Long-term exposure to radiation in space, little gravity causes our muscles to atrophy, lack of medical facilities and medical professionals, people living together for long periods, and it takes a lot of time

Frame of reference

what we use to compare motion

Inertia

resistance to change

Velocity

a speed with a direction. It is a rate

solve velocity problems using v = d/t.

state the unit for velocity

km/hr(distance/time)

define acceleration

the rate of change in velocity(speed)

state the unit for acceleration

Distance/time/time

solve acceleration problems using a = vf – vi / t

solve free fall problems

recognize the acceleration due to gravity (g).

use g = 9.8m/s2 any time something is vertical

define terminal velocity

the fastest speed at which something can fall

Contact force

force caused by contact

Field force

a force exerted over an area around the source

state Newton’s 3 laws of motion in your own words

The force exerted on an object by an object is exerted equally in the opposite direction(you push thing, thing push back)

recognize examples of Newton’s 3 laws of motion

Gun recoil, your chair holding you up, pushing off a wall in a pool

Friction

A force acting against change

Sliding friction

friction caused by two objects sliding

Rolling friction

friction at the point of contact of a wheel

solve 2nd law problems using a = F/m

describe how Newton’s 3rd law applies to jets, rockets, etc.

as the rocket pushes the gases out, the gas pushes back up against the rocket

define momentum

a measure of how difficult it would be to stop a moving object

the relationship between force and time in a momentum change

The longer it takes to stop, the less force you expirience

solve momentum problems using p = mv

I gave up. You got it!!!

define friction

a force that resists motion

describe how friction influences the motion of an object

friction slows down an object

1. give the Hawks' definition of energy and explain why it is better

The ability to cause change. It’s better because it doesn’t lead to a circular definition and it’s better to visualize.

2. define potential energy

energy that’s stored due to position or composition ex. gravitational potential and elastic potential

3. solve potential energy problems using PE = mgh

4. state the first law of thermodynamics

matter and energy cannot be created or destroyed

5. define kinetic energy

the energy of motion

6. solve kinetic energy problems using KE = ½ mv2

7. identify types of energy in different examples

1= gravitational potential, 2= elastic potential, 3= chemical potential 4= kinetic, 5= thermal, 6= nuclear potential 7= electromagnetic

8. define work

the movement of a mass due to a transfer of energy resulting from an applied force

9. calculate work using W = Fd

10. define power

it is the rate of work done over time

11. calculate power using P = W / t

1. define medium

the matter that is disturbed by a wave

2. define wave

a repeating disturbance that travels through either matter or space, accompanied by a transfer of energy.

3. define pulse

a disturbance that happens only one time

4. explain the difference between mechanical and electromagnetic waves

mechanical waves require a medium to travel while electromagnetic don’t

5. label the parts of a transverse wave

1= crest 2= wavelength 3= amplitude 4= trough

6. label the parts of a longitudinal wave

1= compression 2= rarefaction 3= wavelength

7. define frequency

the rate at which something occurs or is repeated over a particular period of time or in a given sample.

8. define wavelength

The distance from one point on a wave to the identical point on the next wave

9. explain the difference between a transverse wave and a longitudinal wave

the energy of transverse waves travel perpendicular to the energy, but longitudinal waves travel parallel to the energy

10. define and recognize examples of reflection

waves bouncing off a boundary ex. mirrors

11. define and recognize examples of refraction

waves bending when changing medium ex. A straw in a glass of water

12. define and recognize examples of diffraction

waves bending around a barrier ex. the fuzzy edges of shadows

13. define and recognize examples of interference

waves interacting with each other

14. explain the difference between constructive and destructive interference

constructive interferencemakes the wave bigger, while destructive interference makes it smaller

15. explain how the human ear hears sound

the eardrum matches the sound waves and vibrates the ossicles(tiny bones in your ear) which vibrate your hair cells in the cochlea then, the auditory nerve turns the vibrations into electricity(we don’t know how)

16. make analogies between waves and the sound you hear

Loudness is related to amplitude. Pitch is related to frequency / wavelength. Timbre is related to shape.

17. recognize visual representations of sound and describe them as loud, quiet, high pitched,  low pitched, etc

Loudness and quietness relate to the height(amplitude) of the waves and pitch relates to frequency

18. list and recognize the four ways that instruments make sound

Vibration of a membrane, air column, reed, or string

18b. Name an example of a membrane, air column, reed, and string

membrane: drum. air column: flute. Reed: oboe. String: violin

19. discuss the Doppler effect

As an object speeds up, it begins to catch up with its sound waves. This creates a higher frequency. As the object moves away from you, the waves come further apart making it sound lower-pitched

20. explain how the Doppler effect is used in weather and police radar guns

it aims sound waves at objects and calculates the distance based on the frequency of the sound waves returning

21. define mach

the unit of the speed of sound

22. describe how a sonic boom is produced

As something hits the speed of sound, the sound waves it’s making line up with the sound waves previously ahead and create a sonic boom

23. describe the range of the sonic spectrum (deepest, highest, faintest sounds)

Frequency: 20Hz-20000Hz Volume: 0dB-120dB+(threshold of pain)

1. discuss the different theories on what light is

Particle: Democritus and Newton

Wave: Aristotle, Faraday, Maxwell, and Thomas Young

Both: Max Planck, Albert Einstein, DeBroglie and Heisenberg

2. list the electromagnetic spectrum in order from lowest to highest frequency

Radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma ray

GPS, radar, and TV satellites are all examples of what?

Radio waves

Microwaves are an example of what type of wave?

Microwaves

What type of wave is used to detect heat?

Infrared

Radiographs, fluoroscopy, and CT scans are examples of what wave?

X-rays

PET scans, bone scans, and radiation therapy are examples of what wave?

gamma rays

4. list the colors of visible light from lowest to highest frequency.

Red, orange, yellow, green, blue, violet

5. explain how the human eye sees light

the light passes through the cornea which bends the light toward the iris which determines how much light is let into the eye. The lens puts the light in the right spot, and the rods and cones determine what you see

6. state what the rod cells in the eye detect

light intensity

7. state what the cone cells in the eye detect

color

8. list the primary colors of light

red, green, blue

9. list the primary colors of pigment

cyan, magenta, and yellow

10. predict the results when light colors

Red+green=yellow, Blue+green= cyan, blue+ red= magenta, and red+blue+green= white

10b. predict the results when pigment colors are mixed

Magenta+cyan=blue, magenta+yellow= red, yellow+cyan=green, blue+magenta+yellow= black

11. explain why the sky is blue, why sunsets are red, how rainbows are formed, etc

Blue and purple are the colors that get bent the most when entering the atmosphere, so at midday, the sky appears blue. It’s the same for sunsets except reds and oranges get bent the least, so you see reds.

1. list the two types of electrical charge.

positive and negative

2. define static electricity

Electricity built up on an insulator

3. define conductor.

a material that encourages the flow of electricity

4. define insulator.

a material that does not encourage the flow of electricity

5. list and describe the three ways of charging an object.

Friction, induction, and conduction

6. state the law of electrostatics.

Opposite charges attract. Like charges repel.

7. describe how electrical impulses travel in your nerves.

Energy goes from one nerve to another through the synapse. It gets across using neurotransmitters

8. define synapse

the gap between neurons in your brain

9. explain the role of neurotransmitters.

responsible for carrying different types of charge and regulating mood, attention, motivation, etc