Transcript Basics

The Basics
Introduction to Foundations of
Science
Presented by April Senger
Units of Measurement
Length: The straight-line distance between
any two points
Mass: A measure of the quantity of matter
in an object
Volume: A measure of space.
Weight: The force with which gravity pulls
on a quantity of matter
A system of communication observations
with labels
Presented by April Senger
Measurement Facts
The le Systeme Internationale d’ Unites is
abbreviated SI and is used worldwide
V, A, l, w, etc are all units & m2, m/s2 are derived
units
Length is in meters, mass in grams, volume in
liters, time in seconds, temperature in Kelvin,
electrical current in ampere, amounts of
substances in moles, and luminous intensity in
candelas…m, g, s, K, A, mol, and cd
Presented by April Senger
More Facts…
Prefixes to know are:
Nano
n
billionth
.000 000 001
Micro
µ
millionth
.000 001
Milli
m
thousandth
.001
Centi
c
hundredth .01
Deci
d
tenth
.1
Kilo
k
thousand
1000
Mega
M
million
1 000 000
Giga
G
Billion
1 000 000 000
Presented by April Senger
Variable
Variables are anything that can change in
an experiment
Things that you can change…Sometimes
represented by a letter of the alphabet
The best experiments only test one
variable at a time
Common variables in science are v, t, & d
There are three kinds of variables:
controlled, independent, and dependent
Presented by April Senger
Conversions
Using multiples to change one unit of
measurement to another
Changing one measurement into another
Presented by April Senger
Cool Facts
I may call this “doing conversions” or “the
factor label method”
Ex: You have 15 one dollar bills. How
many quarters is that worth?
Step 1: List the givens and unknowns
Given: 15 dollars
Unknown: ? Quarters
Presented by April Senger
Example Continued…
Step 2: Determine the relationship
1 dollar = 4 quarters
Step 3: Write down the conversion fraction
Dollars x 4 quarters
Dollars
Step 4: Insert your knowns
15 Dollars x 4 quarters
Dollars
Presented by April Senger
Exclusions
Temperature conversions are more
complex and do not work with this method:
0º C = 32º F
37º C = 98.6º F
100º C = 212º F
Presented by April Senger
Graphing
Graphs are visual means
of representing data
collected
Independent variables
always go on the x-axis
Dependent variables
always go on the y-axis
Line graphs are best for
data with changes Ex:
Time (independent) and
Volume (dependent)
Bar graphs are best for
individual data or events
Ex: Melting points
(dependent) and kinds of
metal (independent)
Pie charts are best for
displaying the parts of a
whole Ex: The % of
gases in our atmosphere
Presented by April Senger
Scientific Notation
Scientific notation is a value written as a
simple number multiplied by a power of
ten
Changing very large or small numbers into
easier numbers to work with
Presented by April Senger
Notation Facts
The Steps for solving
Step 1: List the givens and unknowns
Step 2: Write the form for Sci Notation
Step 3: Insert known values and solve
The speed of light is 300,000,000 m/s and
the distance to Neptune is
4,600,000,000,000 m to Earth. To
calculate the time it would take light to get
there you could:
Presented by April Senger
Example
t = 4,600,000,000,000 m = 4.6 x 1012 m
300,000,000 m/s
3.0 x 108 m/s
t = 1.53 x104 s
When multiplying 2 numbers you add the
powers of ten
When dividing you subtract the powers of ten
Presented by April Senger
Precision & Accuracy
Precision is the degree of exactness of a
measurement. Accuracy is the extent to
which a measurement approaches the true
value
Precision is getting the exact number
again and again. Accuracy is getting the
right number
Presented by April Senger
Cool Facts
A measurement is only as accurate as the
tool used to measure it
Dart Board Ex of Precision
Presented by April Senger
Continued…
Dart Board Ex of Accuracy
Presented by April Senger
Significant Digits/Figures
The digits in a measurement that are
known with certainty.
The number of digits we should use with
confidence
Presented by April Senger
Sig Figs In Action
1.543, 13.50, 1940., and 4053 have 4 sig
figs
1.5, 57, 90., .0086, and .45 have 2 sig figs
All zeros count except place holders 480
or .04
Rounding up and down follow these rules
3.45 rounds to 3.4 because it is even
3.55 rounds to 3.6 because it is odd
Presented by April Senger
More Facts
When multiplying or dividing numbers you
round to the smallest number of sig figs
Ex: 5.43 x 23.56 = 127.9308 = 128
When adding or subtracting you use the
smallest number of decimal places being
added or subtracted
Ex: 3.456 + 45.35 = 48.806 = 48.81
Presented by April Senger