THE ANSWERS!!!!! October 16, 2007

SCIENCE – The Scientific Method and Heat Energy Section #/color: ____ / ______

The Scientific Method and Heat Energy

“Can” you take the heat (or leave it)?

Lab Experience #2

Applying our Scientific Method and Heat Energy Knowledge

A GRAPHING LESSON…How to make a great graph!

KEY WORDS:

Independent Variable / Dependent Variable / X-axis
Y-axis / Trend / Best-fit line
Extrapolate / Interpolate / Extraneous data or Outlier

Before we make a triple-line graph of our can lab data both by hand as well as by computer, we need to define a few things about our data and graphs in general. Let’s fill out the info below.

QUESTIONS 1 and 2:

INDEPENDENT / DEPENDENT
The variable that the scientist changes and has control over (the manipulating variable). / The variable that changes as a result of changes in the independent variable (the responding variable).
X-AXIS / Y-AXIS

2)  What is the independent variable for our data? ______time in minutes______

3)  What is the dependent variable for our data? ______temperature in °C______

4)  What are the 10 rules for making a “great” graph? Think about your rules…and then look at Mrs. P’s rule sheet! J How do they compare? SEE MY HANDOUT! J

5)  What is the “trend” of a graph?

A overall and PRESENT relationship between the independent and dependent data. i.e. the general “flow” of the data – there may not always be one!

6)  What is a best fit line and how do you make one?

A line that visually shows the trend of the data. Align your ruler so there is an even amount of data points on, below and above it. THEN DRAW A STRAIGHT LINE!

7)  What is an “outlier” or “extraneous data”? What should you do when you have one?

One or two data points that do not fit an overall trend. Usually shows there’s been a mistake or some outside influence (an uncontrolled variable). To deal with them, try to think about why they exist…recognize their importance or lack of importance on the overall data set. They are usually not included in the trend/best-fit line.

8)  What does it mean to “extrapolate” and “interpolate”?

extrapolate – to predict a data point beyond the range of data using the best fit line.

Interpolate – to predict a data point not measured but within the range of data using the best fit line.

9)  Why do we make graphs in the first place?

To show “in pictures” what data looks like – helps us to see trends and relationships!