Science final Flashcards

critical thinking

comparing what you already know with the information you are given in order to decide whether you agree with it

Hypothesis

possible explanation for an observation that can be tested by scientific investigations

inference

logical explanation of an observation that is drawn from prior knowledge or experience

observation

using one or more of your senses to gather information and taking note of what occurs

preditction

statement of what will happen next in a sequence of events

science

the investigation and exploration of natural events and of the new information that results from those investigations

scientific law

rule that describes a repeatable pattern in nature

scientific theory

explanation of observations or events that is based on knowledge gained from many observations and investigations

technology

practical use of scientific knowledge, especially for industrial or commercial use

description

spoken or written summary of observations

explanation

interpretation of observations

International System of Units (SI)

internationally accepted system of measurement

percent error

expression of error as a percentage of the accepted value

scientific notation

method of writing or displaying very small or very large numbers

constant

factor in an experiment that stays the same

control group

contains the same factors as the experimental group, but the independent variable is not changed

dependent variable

factor you observe or measure during an experiment

experimental group

used to study how a change in the independent variable changes the dependent variable

independent variable

factor that you want to test; is changed by the investigator to observe how it affects a dependent variable

qualitative data

words used to describe what is observed

quantitative data

numbers used to describe what is observed

variable

any factor that can have more than one value

meter

SI unit of length

kilogram

SI unit for mass

ampere

SI unit of electric current

candela

SI unit for luminous intensity

kelvin

SI unit for temperature

mole

SI unit used to measure the amount of a substance

second

SI base unit for time

dimension

distance or length measured in one direction

displacement

the difference between the initial position and the final position of an object

motion

the process of changing position

position

an object's distance and direction from a reference point

reference point

the starting point you choose to describe the location, or position, of an object

relative

considered in relation or in proportion to something else. Compared to

specify

to indicate or identify

average speed

total distance divided by total time

constant speed

the rate of change of position in which the same distance is traveled each second

instantaneous speed

speed at a specific instant in time

speed

The distance an object travels per unit of time

velocity

the speed and direction of a moving object

acceleration

a measure of the change in velocity during a period of time

average acceleration

the change in velocity divided by the time during which the velocity changes

horizontal

limit, divide, separate; x-axis on a graph

vertical

overhead; y-axis on a graph

force

a push or pull upon an object

balanced force

when forces on an object are of equal magnitude and in opposite directions; no acceleration

unbalanced force

when forces on an object do not cancel out; causes acceleration

net force

the sum of all the forces acting on an object

friction

a force that opposes motion between two surfaces that are in contact

static friction

the force that resists the initiation of sliding motion between two surfaces that are in contact and at rest

inertia

the tendency of an object to resist a change in motion unless an outside force acts on it

weight

the measure of the force of gravity on an object

Mass

The amount of matter in an object

Newton

SI unit of force. Measure equals the force required to accelerate one kilogram of mass at 1 meter per second

Rolling Friction

Friction that occurs when an object rolls over a surface

Acceleration

The rate at which velocity changes

You are riding a bike, you hit a rock and you fly off the bike into the mud in front of the bike.

1st Law

It is harder to stop a train than a car if both are going 50 miles per hour.

2nd Law

A rocket is pushed into space by the burning fuel.

3rd Law

Christian's science book sits on his desk until he opens it.

1st Law

Newton's Second Law of Motion-Definition

The acceleration of an object depends on the mass of the object and the amount of force applied.

Newton's Third Law-Definition

For every action there is an equal and opposite reaction

Which type of friction keeps an object at rest?

static friction

contact force

A force that is exerted only when two objects are touching.

gravity

A force of attraction between objects that is due to their masses.

centripetal force

a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving.

circular motion

any motion in which an object is moving along a curved path

momentum

The product of an object's mass and velocity

Law of Conservation of momentum

law stating that the total momentum of a system does not change if no net force acts on the system

power

rate at which work is done

work

transfer of energy to an object by a force that makes an object move in the direction of the force

efficiency

ratio of output work to input work

mechanical advantage

ratio of output force to input force

fulcrum

point about which a lever pivots, or rotates

inclined plane

flat, sloped surface

lever

made up of a bar that pivots about a fixed point

pulley

grooved wheel with a rope or cable wrapped around it

screw

inclined plane wrapped around a cylinder

simple machine

a machine that does work using only one movement

wedge

sloped surface that moves

wheel and axle

made up of a shaft, or axle, attached to the center of a wheel such that both rotate together

joules (J)

SI unit for work

class 1 lever

A lever in which the fulcrum is between the load and the effort.

class 2 lever

A lever in which the load is between the fulcrum and the effort.

class 3 lever

A lever in which the effort is between the fulcrum and the load

newton

SI unit of force

meter

SI unit of length

second

SI base unit for time

mechanical advantage of pulley

number of lengths of rope supporting the load

Efficiency

The percentage of the input work that is converted to output work (output work / input work)

example of a wedge

knife

example of an inclined plane

ramp

example of wheel and axle

door knob

example of a screw

jar lid

example of a lever

scissors

example of 1st class lever

see saw, crow bar, plier, screw driver, stapler, scissors

example of 2nd class lever

wheel barrow, door, nut cracker, bottle opener, light switches

example of 3rd class lever

tweezers, fishing pole, rake, tongs

3 ways machines make work easier

1. increase force applied to the object