unit 1 lesson 4 representing data copyright © houghton mifflin harcourt publishing company

Unit 1 Lesson 4 Representing Data

Copyright © Houghton Mifflin Harcourt Publishing Company


Florida Benchmarks


• SC.8.N.1.5 Analyze the methods used to develop a scientific explanation as seen in different fields of science such as biology, geology, and physics.

• SC.8.N.1.6 Understand that scientific investigations involve the collection of relevant empirical evidence, the use of logical reasoning, and the application of imagination in devising hypotheses, predictions, explanations and models to make sense of the collected evidence.


Florida Benchmarks


• SC.8.N.3.1 Select models useful in relating the results of their own investigations.

• MA.6.A.3.6 Construct and analyze tables, graphs, and equations to describe linear functions and other simple relations using both common language and algebraic notation.


Florida Benchmarks


• LA.8.4.2.2 The student will record information (e.g., observations, notes, lists, charts, legends) related to a topic, including visual aids to organize and record information, as appropriate, and attribute sources of information.

Modeling Data with Graphs


How do scientists make sense of data?

• All of the different types of scientific investigations involve the collection of data.

• Data are the facts, figures, and other evidence scientists gather when they conduct an investigation.

• Scientists organize and record their data in data tables.



• Data tables often have two columns.

• One column lists the independent variable, which is the variable that is deliberately manipulated in an investigation.

• The other column lists the dependent variable, which is the variable that changes as a result of manipulation of the independent variable.




• Scientists often analyze data for patterns or trends by constructing graphs of the data.

• The type of graph they construct depends upon the data they collected and what they want to show.




• A scatter plot is a graph with points plotted to show a possible relationship between two sets of data.

• In a scatter plot, the horizontal x-axis usually represents the independent variable.

• The vertical y-axis usually represents the dependent variable.

• To show the general relationship between the two variables, a “line of best fit” may be used.



More Graphing!


What do graphs show?

• Scientists use different types of graphs to show different types of information about data.

• A bar graph is used to display and compare data in a number of separate categories.

• A circle graph is used to show how each group of data relates to all of the data.


Throw Me a Curve!


What kinds of patterns can be shown using graphs?• When you graph data, you can identify what the

pattern, or trend, of the data is.

• A trend shows the relationship between the two variables studied in the experiment.

• Graphs make it easy to tell if something is increasing, decreasing, or staying the same.


What kinds of patterns can be shown using graphs?• In some cases, a line can be used to show the

trend of data on a graph.

• If the relationship between the independent and dependent variables can be shown with a straight line, the graph is called a linear graph.

• A straight line shows that the rate of change of the dependent variable with respect to the independent variable is constant.



What kinds of patterns can be shown using graphs?



• The density of water as a function of temperature is a linear relationship.

What kinds of patterns can be shown using graphs?• A graph in which the relationship between the

variables cannot be shown with a straight line is called a nonlinear graph.

• If the product of variables remains constant, the variables are said to have an inverse relationship.

• A graph of an inverse relationship is a smooth curve that becomes nearly vertical and horizontal at opposite ends.



What kinds of patterns can be shown using graphs?



• The relationship between volume and pressure for a gas at a constant temperature is a nonlinear relationship.

The Perfect Model


How do scientists select models?

• Scientists use many different kinds of models.

• Some are physical models, such as maps and globes.

• Others are mathematical models, including equations and simulations of movement.



• A model is a representation of an object or a process that allows scientists to study something in greater detail.

• A model that is too simple or too complicated may not be useful.

• The best models are those that most closely resemble the system, process, or other entity they represent.




• Scientists select models based on how much the models can explain.

• In addition, scientists select models based on how few limitations they have.

• Today, many phenomena in science can be modeled with great sophistication.



unit 1 lesson 4 representing data copyright © houghton mifflin harcourt publishing company

Documents

data slide

sense of data

data tables

collection of data

modeling data

sets of data

evidence scientists

independent variable