Name: Per: ______Date: ______#:______

Lab #____: Graphs Data Tables in the Science Lab

Background:
One of the things most often seen in a description of any scientific experiment is a graph or table. A graph is a visual representation of numerical data collected from an experiment. Some of the types you’ll find in science are bar and pie graphs. The one used most often however, is a line graph.

Line graphs describe the relationship between two variables. Each variable is plotted along an axis. A line graph has a vertical axis and a horizontal axis. The “x-axis” is where scientists plot the independent variable and the “y-axis” is where they plot the dependent variable.

  • They show specific values of data, meaning that given one variable the other can easily be determined
  • The Y axis shows trends in data clearly, meaning they visibly show how one variable is affected by the other as it increases or decreases
  • They allow the reader of the graph to make predictions about the results of data not yet collected

Purpose:

  • To refine our skills at graphing collected data
  • To better understand how to “interpret” the data on a graph
  • Be able to graph data from a given table of raw data

Part A: Interpreting tables

  1. Using data table 1.1 below, answer the following questions:

Distance of Light From the Plant (cm) / Number of Bubbles per Minute produced by Plant
10 / 60
20 / 25
30 / 10
40 / 5

Data Table 1.1

a)Which column represents the independent variable?

b)Which column represents the dependent variable?

c)What is a conclusion that can be drawn from data table 1.1?
(Hint: First think what happens to the distance of light from the plant as you read down the column? What happens to bubbles per minute as you read down the column? Your answer should include both trends!)

  1. Using data table 1.2 below, answer the following questions:

Data Table 1.2

Test Tube / Temperature (°C) / Bubbles of Oxygen per Minute
1 / 0 / 3
2 / 10 / 22
3 / 20 / 40
4 / 30 / 58
5 / 40 / 71
6 / 50 / 2

a)At what temperature will the most oxygen be produced?

b)Between which temperatures will oxygen production decrease?

c)What Is a conclusion that can be draw from data table 1.2?

Part B: Interpreting Line Graphs

The following are a few examples of line graphs. These lines represent the RATE at which something occurs. Answer the following questions based on graphs A-F

1. Which line represents a tree, which has not grown over time? ______

2. Which graph shows an increase, then a decrease? ______

3. Which graphs show an increase in rate? ______

4. Which graph shows a constant rate increase over time? ______

5. Which graphs show a decrease in rate?______

6. Which graph shows a slow increase in rate that speeds up? ______

Part C: Determining Data From Graphs

Base your answers to the following questions on the graph below

  1. After 4 hours have passed, what percent of the protein has been digested?
    _____
  1. How long does it take for 25% of the protein to be digested? _____
  1. At which of the following time intervals does the most rapid increase in rate occur?

a. 0-8 hrs
b. 8-16 hrs
c. 16-24 hrs

  1. At approximately how many hours does the rate of protein digestion remain constant?
    ______
  2. What is the independent variable from the graph above?
  3. What is the dependent variable from the graph above?
  4. State the relationship between time and the % of protein digestion.

Part D: Creating Graphs

A group of biology students extracted photosynthetic pigments from spinach leaves using the solvent acetone. A spectrophotometer was used to measure the percent absorption of six different wavelengths of light by the extracted pigments. The wavelengths of light were measured in units known as nanometers (nm).

The following data was collected:

  1. Create a data table to organize your results so that the wavelengths are increasing

Color of Light / Wavelength of Light (nm) / Percent Absorption by Spinach Extract
  1. What is the independent variable?
  2. Which axis of the graph will be labeled?
  3. What is the dependent variable?
  4. Which axis of the graph will be labeled?
  5. What will be the title of your graph?
  6. Graph your data on the graph on the next page. Be sure to:
  7. Add your title to your graph
  8. Label the axes
  9. Create a proper scale for each axis
  10. CIRCLE your data points

Answer the following questions based on your graph from above:

  1. What wavelength of light does spinach leaves absorb the best?
  1. What color light does spinach leaves absorb the least?
  1. What is a conclusion (relationship or trend) that can be drawn from the graph?