Sept. 11 Pg. 12

Focus: Scientific Inquiry Skill: Graphs

Objective: Scientists gather and organize data

Homework: data table, parent signature

Warm Up: Answer

1.Write the steps for creating a data table.

2.What is a graph? How is it different from a data table?

How am I doing?

4 columns

• Date Assessment Title Grade Signature

Table of Contents

4 columns

• Page Number Date Focus Objective #

Draw the Axes

Identify the Axes

Y- Axis

X- Axis

Identify the Axes

Y- Axis

X- Axis

Dependent Variable(what is

observed and measured)

Independent Variable

(what is changed by the scientist)

One way to remember which data goes on which axis is the acronym DRY MIX.

D.R.Y. M.I.X.

D- Dependent M- Manipulated

R- Responding I- Independent

Y- Y-axis X- X-axis

DRY MIX

Title

• Write an appropriate title for the graph at the top.

• The title should contain both the independent and dependent variables.

Scale

• Decide on an appropriate scale for each axis.

• The scale refers to the min and max numbers used on each axis. They may or may not begin at zero.

• The min and max numbers used for the scale should be a little lower than the lowest value and a little higher than the highest value.

• This allows you to have a smaller range which emphasizes the comparisons/trends in the data.

Scale

•The Y-axis scale is from 0-100.

•The largest value though is only 35.

Scale

•The Y-axis scale is now from 0-40.

•This does a better job emphasizing the comparisons between coins.

Intervals

• Look at your minimum and maximum values you set up for both the Y and X-axis. (For most bar graphs, the X-axis will not have numerical values.)

• Decide on an appropriate interval for the scale you have chosen. The interval is the amount between one value and the next.

• It is highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc.

Intervals

The interval for the Y-axis is 20.

The X-axis does not have numerical data and does not need an interval.

Labels

• Both axes need to be labeled so the reader knows exactly what the independent and dependent variables are.

• The dependent variable must be specific and include the units used to measure the data (such as “number of drops”).

Labels

DV label

IV label

Another handy acronym to help you remember everything you need to create your graphs…..

T.A.I.L.S.

Title

Axis

Interval

Labels

Scale

TAILS

TAILS

Title: Includes both variables

Axis: IV on X-axis and DV on Y-axis

Interval: The interval (4) is appropriate for this scale.

Label: Both axes are labeled.

Scale: Min and max values are appropriate.

Graphing Rules Notes

Purpose of a Graph: to show data visually

Bar graphs: used for data that is not connected, such as types of vegetables

Title

Y axis label

X axis label

Independent Variables

100

90

80

70

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0

Dependent Variables

Bars

Title Vegetable Choices of Guinea Pigs

Y axis label

Percentage of Food Choice

X axis label Food Choices

Independent Variables Carrots Broccoli Lettuce

100

90

80

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Dependent Variables

Discontinuous Data: Bar Graph

How to Make a Bar Graph

1. Dependent Variable: y-axis

2. Independent Variable: x-axis

3. Number the y-axis

4. Label the x and y-axis

5. Draw a bar for each data value

6. Label each bar

7. Give your graph a title

Graphing Rules Notes

Purpose of a Graph: to show data visually

Line graphs: used for data that is connected, such as over a period of time. Lines consist of connected dots.

Line Graph• A line graph is a

graph used to show change over time!!

What can time be measured in???Seconds - Minutes - Hours – Days - Weeks - Months – Years - Decades -

Centuries - etc.

When to use a line graph? Would we use a line graph

in the following situations:

•To show how many people like pizza in this class? NO

•To show how many people live in East Meadow? NO

•To show how much it rained each month this year? YES- because months and years deal with time.

How do we make a line graph?

• A line graph ALWAYS has a title!

• A line graph has two different axis’s

• An axis is either the horizontal line (called x) or the vertical line (called y) that form the base lines of a graph.

Y

X

                     

Title

Y axis label

X axis label

Independent Variables

100

90

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70

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10

0

Dependent Variables

Points

Plotting a Line graph• When we are plotting a line graph, it is

important to read what information is on each axis.

• There must be a label on each axis that describes the information.

• Much like a bar graph, we look at the x-axis first in order to plot our points.

Time in minutes

Year

Number of Cases of Lead

Exposure

1987 1044

1988 789

1989 884

1990 653

1991 690

1992 807

1993 1900

1994 1988

1995 1718

1996 1382

1997 1156

Is this an acceptable graph?

Time

Car Trip

Bar Graphs vs Line Graphs

Bar Graphs

•Bar graphs are descriptive.

•They compare groups of data such as amounts and categories.

•They help us make generalizations and see differences in the data.

Example

Another example

Line Graphs

•Line graphs show a relationship between the two variables. They show how/if the IV affects the DV.

•Many times, the IV plotted on the X-axis is time.

•They are useful for showing trends in data and for making predictions.

Example

Another example