Download Lab 2: Background information Ways of expressing data Numerical

Lab 2: Background information
Ways of expressing data
Numerical figures can be very large or very small
Scientists use SCIENTIFIC NOTATION to express numbers
B X 10E E = exponent
B = base
1< number < 10
The metric system is based on 10
103 = 1000
10-2 = 0.01 = 1/100
If there is a positive exponent, then you add that number of 0s.
You move the decimal point to the right.
If there is a negative exponent, then that is how many decimal places there are before the
number.
You have moved the decimal point to the left that many of places.
7.23 X 103 = 7230
7.23 X 10-3 = .00723
Look at section 2.2, question 2 and convert the numbers to scientific notation
Numbers can also be expressed in decimal notation.
9.83 X 10-3 = 0.00983
Look at section 2.2, question 3 and convert the numbers to decimal notation
Multiplication of numbers
Multiply the bases and add the exponents.
(2.1 X 109) X (4.3 X 1012)
= 2.1 x 4.3 = 9.03
10(9 + 12) = 1021
Answer = 9.03 X 1021
If the base > 10, you need to express it in a form that is less than 10 to be using CORRECT
scientific notation.
(2.3 X 108) X (5.8 X 106) = 13.34 X 1014 = 1.334 X 1015
Remember, multiply the bases and add the exponents but you must express the base <10.
Move the decimal to the left and add one to the exponent.
If the number is <1, you must make it greater than 1.
You would move the decimal to the right one place and subtract the exponent by 1.
Look at section 2.2, question 4 and do the calculation requiring multiplying numbers
(adding exponents).
Division of numbers
Divide the bases and subtract the exponents.
8 X 103 = 8 X 103 = 8 X 10(3-8) = 2 X 10-5
4 X 108 4
108 4
If the answer results with the base is <1 or >10, you must correct it to get the answer
in correct scientific notation.
4 X 103 = 0.5 X 10-5 = 5 X 10-6
8 x 108
Look at section 2.2, question 5 and do the calculation requiring dividing numbers
(subtracting the exponents).
Section 2.3 Look at other document showing how to convert between different units in the
metric system.
Standard units in the metric system:
meter = m = length
gram = g = mass (weight)
liter = l = volume
degree celcius = °C = temperature
can combine these different standard units with prefixes and suffixes
milli, centi, kilo, etc.
If you go from smaller to larger, you move the decimal point to the left or decrease the exponent.
If you go from larger to smaller, you move the decimal point to the right or increase the
exponent.
You will always have more of the smaller units than the larger units.
ng
103
g
103
mg
Examples:
Going from smaller to larger
103 ng = 103 - 3 = 100 = 1 g
10 mg = 1 cg
103 g = 1 kg
1g = 10-3kg
1 ng = 1012 kg
Going from larger to smaller
1 kg = 103 g
10
cg
10
dg 10
g
103
kg
Look at section 2.3, question 6 and do the problems requiring you to convert between
different units.
You will also need the following formulas to do the temperature conversion.
°C = (°F - 32) X 5/9
°F = (°C X 9/5) + 32
Graphing
You should have a title on each graph and label the X and Y axes.
Line graph:
each value represented by one point
points represented by a straight line
continuous variables
the points are related to each other
for example: how long student held breath after different times of exercise
can have more than one line in a graph - from last week, each line would
represent a different student
This is a graph of the results from last week. I have only shown one person.
Each person who did the experiment should have a line.
Bar graph
Discrete variables
No intermediate values
The points are not related
For example: if we take 4 different students and take the values for how long each held
his/her breath after1 minute of exercise.
Look at section 2.4 and answer the questions on graphs.