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Scientific Method

- Gather Data, find patterns, make a hypothesis, make a prediction, gather data again.

Gathering Data

Observation & Experimentation (placebo, control group, blind/double blind)

Placebo

Testing new medicine - sugar pill - psychological impact - neither group knows if you're getting medication. *measure both groups

Blind/Double Blind

Person giving medication doesn't know what pill is which, so they don't act differently when administering the medication

In the gathering data step of the scientific method, both observations and experiments must be performed?

Yes

Hypothesis

A tentative explanation of some regularity of nature, based on patterns in data.

Theory

A thoroughly tested explanation of basic natural phenomena.

Law of Nature

A concise statement or mathematical equation about a fundamental relationship or regularity of nature.

A hypothesis is...

A tentative explanation for a natural phenomenon

Prediction

A statement, made in advance, about what one believe will happen or how a particular system will behave - in the scientific method - the prediction is based on the hypothesis

The scientific method, which is very useful in many fields besides science, is simply...

A systematic way of evaluating evidence

Pseudosceience

Use of vague, exaggerated or untestable claims, or untestable claims

Mechanics is concerned with:

The behavior of physical bodies when forces act on them. The effect of moving bodies on their environment.

The Universe

regular and predictable, the universe is not random. It moves in regular, predictable ways.

Planetary Motion:

Ptolemy - geocentric model of universe, copernicus - heliocentric model of universe, Kepler and Brahe - elliptical orbits

Ptolemaic and Copernicus systems assumed?

All orbits are circular

Mechanics

Branch of physics that deals with the motion and the forces that act on them

Kinematics

The description of motion - Galileo

Dynamics

The explanation of motion - Newton

Speed

the distance an object travels per unit time: s=d/t

Velocity

speed with a direction

Acceleration

the change in velocity of an object per unit time - a=v2-v1/t2-t1

Uniform motion

no change in speed or direction

Acceleration

a change in speed or direction - that is, a change in velocity

Galileo's experiments showed?

All objects fall at the same rate regardless of their mass and the velocity of a falling object that starts from rest is proportional to the length of time that it has been falling: v(m/s)=a(m/s2)xt(s)

Distance is proportional to:

the square of the time traveled d=1/2xaxt2

Earth's gravitational acceleration

g=9.8m/s2

Kepler described

planetary motion

Galileo described

motion of falling objects

Newton explained

why things move

Newtons 1st law of Motion:

every object continues in its state of rest, or in uniform motion, unless it is compelled to change that state by forces impressed upon it.

The greater the force,

the greater the acceleration. a=f/m or f=m*a

Newton's 2nd law of Motion:

The acceleration produced on a body by a force is proportional to the magnitude of the force and inversely proportional to the mass of the object

Newton's 3rd law of Motion:

between any two objects, there is an attractive force proportional to the product of the two masses divided by the square of the distance between them f=g**m1**m2-d2