unit 2: measurement & data

Unit 2:

Measurem

ent & Data8th Grade

Mrs. Morgan

Review: Once AgainData- the facts, figures, and other evidence scientists gather when they conduct an investigation.

Independent variable- (x axis) the variable that is deliberately manipulated (changed on purpose)

Dependent variable-(y axis) changes value as others change.

3 Types of Graphs 1. line graph shows relationship where

the dependent variable changes b/c of the independent variable

• Scatter plot

http://4.bp.blogspot.com/_46URaoUSp0A/S9B6OMq9qfI/AAAAAAAAAGE/IcQA37CwMT4/s1600/scatterplot.gif

2. Bar graph

compare information collected by counting.

3. Circle or Pie graph show how a whole is broken into parts.

Reading Graphs• Linear relationship-the relationship

between the independent and dependent variable can be shown with a straight line.

• Nonlinear relationship-any relationship between the variables that cannot be shown with a straight line.

Direct relationship-upward sloping line

Inverse relationship-downward sloping line

Model-representation of an object or a process that allows scientist to study something in greater detail.

Measurement- description that includes a number and unit

SI- improved version of the metric system used worldwide.

Based on multiples of 10.

Base Units

1.Length (m)-distance between 2 points

2.Mass (kg)-how much matter is in an object

3.Time (s)-interval between 2 events

4.Temperature (K or ˚C)- how hot or how cold something is

5.Volume (L, or cm3)-amount of space occupied by an object

Derived unit -combining different SI units Density -mass per unit volume of a material OR simply how packed together something is.

The unit is g/cm3 for example: g=grams and cm3 =volume

kilo-

hecto-

deka-

deci-

centi-

milli-

0.1 =

0.01 =

0.001 =

m

meter

cm

centi-

dm

deci-

mm

milli-

dkm

deka-

hm

hecto

km

kilo-

54 hm = ? cm

54

1. Copy the #2. Find Dewey

m

cm

dm

mm

dkm

hm

km

54 hm = ? cm

3. Move Dewey

0 0 0 0 cmx

540,000 cm

54 hm = ? cm

1 dm = ? m

1

1. Copy the #2. Find Dewey

m

cm

dm

mm

dkm

hm

km

1 dm = ? m

3. Move Dewey

m

x

.1 m

1 dm = ? m

Measurements must have a # & a unit.

.1 m

1 dm = ? m

0

Scientific Notation-short way of representing very large or very small numbers

Accuracy-description of how close a measurement is to the true value of the quantity measured.

Precision-the

exactness of a

measurement.