8th Grade 1-7: Using Graphs in Science

​Science Root of the Day:

DO NOW: Write what you think the example words mean in your lab manual.

Extra Credit: Find three additional words that use this root and write them and their definition in your lab manual (6 Points Max)

​Using Graphs in Science

A census is a survey to get an idea of the population in an area. When so many people turn in their information, it can be difficult to read and understand the data. Various graphs are used to help make the information more clear

Multiple Choice

This variable is the one thing that is changed on purpose...

• independent variable

• dependent variable

• controlled variable

Multiple Choice

True or False: An estimate is an approximation of a number based on reasonable assumptions.

• True

• False

Multiple Choice

Steve wanted to see if the type of fertilizer made sunflowers grow larger. What is the dependent variable?

• Type of fertilizer

• Size of sunflower

• Type of sunflower

Multiple Choice

Which of the following shows the mean for the following set of numbers

15.6, 14.1, 7.7, 12.9, 12.9?

• 7.9

• 12.64

• 13

• 12.95

Multiple Choice

Which of the following shows the Mode for the following set of numbers:

15.6, 14.1, 7.7, 12.9, 12.9?

• 7.9

• 12.64

• 13

• 12.9

Multiple Choice

Which of the following shows the range for the following set of numbers:

15.6, 14.1, 7.7, 12.9, 12.9?

• 7.9

• 12.64

• 13

• 12.9

Lesson Objectives

• Describe why scientists use graphs

• List and describe the parts of the graph

• Understand which graph is appropriate for certain situations

How do Scientists Use Graphs?

• A Graph is a visual representation/picture of your data

  • Graphs are used to

    • identify trends

    • make predictions

    • recognize anomalous/inconsistent data

Types of Data

• Graphs can display two types of data

  • Categorical Data: Data that can be grouped into categories

    • example: Age group

  • Numerical Data: continuous data ranging from small to large amounts

    • example: Temperature, size

• Different types of graphs are used to show different types of data

Parts of Every Graph

• Title: Tells you what Variables are being Compared

• 2 Axis​

  • X-Axis: Your Independent Variable

    • In a bar graph, your categories go here

    • In a Line Graph, this is what you directly change

  • Y-Axis​

    • In Bar graphs, this is your numerical data

    • In a Line graph, this is your dependent Variable

• Scale: How the numbers on your graph increase

  • Must be shown and labeled on both axis

Multiple Choice

What are the numbers on the side of the graph called?

• scale

• title

• data

• variables

Multiple Choice

What is the Dependent Variable in this graph?

• Plant Growth
• Growth (cm)
• Hours
• 15

Multiple Choice

The Independent Variable is represented on which Axis?

• A
• X
• B
• Y

Line Graphs

• Display numerical data

• Can show how a dependent variable changes in response to an independent variable​

• Linear Graph: A line graph in which data points form a straight line

  • Shows a direct relationship between two variables

Line Graphs

• Nonlinear Graph: ​Data points do not fall along a straight line

  • Can still show an overall trend

Types of Line Graphs

• Scatter plot: uses many data points to show an overall trend

  • Outlier: A data point that is not part of an overall trend​

    • Tends to be anomalous data​

When do I Use a Line Graph?

• Whenever you are graphing a change over time

• Whenever the independent variable is a continuous change

  • a large range of temperatures

Bar Graphs

• Show both Categorical and Numerical Data

  • Compares the numerical values of different groups ​

• When to use

  • When you have a non numerical category

Pie Charts

• Shows a statistical comparison of different types of data

  • Mainly used for showing perctanges of something

• Not the best option to show complex data

  • too hard to read large amounts of data

Multiple Choice

True or False: Bar Graphs can Represent Categorical data

• True

• False

Multiple Choice

True or False: If a graph shows no clear trend, it means the variables are related

• True

• False

Multiple Choice

_____ data can be grouped into categories and only represented on a bar graph.

• outlier

• linear

• categorical

• numerical

Multiple Choice

an anomalous data point that is clearly not part of the trend is a(n)

• linear graph

• graph

• outlier

• nonlinear graph