Data Organization: Constructing Data Tables
Scientists collect and record data during their work. They represent this data in many formats, such as tables, narrative notes, graphs, or diagrams. Data can be recorded in different ways depending on the type of investigation and what the scientist is trying to learn. The way in which data is organized is important when interpreting and drawing conclusions from the data.
A data table is one type of graphic organizer used frequently in science. It is used especially during laboratory experiments when qualitative and/or quantitative data are collected. Data tables are not randomly constructed; they have at least two columns or rows and specific data entered into each column and/or row. In order to design a data table, you must know what the independent and dependent variables are.
Let’s look at the procedure of an experiment. Identify the independent and dependent variable. If you need help with identifying the independent and dependent variable, review the lesson titled Experimental Design, in this module.
Every data table needs a title that describes what is in the data table. For example, a title for the data table above would be How the Concentration of Salt Affects the Cooling Rate of Water.
Let’s try another. Look at the following procedure. What would the data table need to look like in order to accurately record the data?
Read the following procedure. Drag the labels to the correct location in the data table. Not all of the labels will be used.
Cars and Ramps Lab
- With the ramp flat on a table or floor, place the back of the car's wheels at one end of the ramp and measure the distance from the front of the car to the end of the ramp.
- Raise the ramp up on one block.
- Place the back of the car's wheels at the top end of the ramp.
- Release the car as you start the stopwatch.
- Stop timing when the front of the car gets to the bottom of the ramp.
- Repeat steps 3-5 two more times, then calculate the average time.
- Raise one end of the ramp on two blocks and repeat steps 2-7.
- Raise one end of the ramp on three blocks and repeat steps 2-7.
Picturing Data: Making Bar Graphs
A graph is a pictorial representation of information recorded in a data table where the independent variable with units are located on the X or horizontal axis and the dependent variable with units are located on the Y or vertical axis. A graph is used to show relationships between two or more different factors. Always use a descriptive title for the graph (how the independent variable affects the dependent variable). It may be the same as the title of the data table.
A bar graph shows a quantitative comparison using a series of columns to display data. Usually, the independent variable is all text; it is not a measurement and therefore, will not have a unit. Look at the following data table and graph.
Multiple bar graphs are used when the dependent variable has more than one group or category. A key or legend should be used to show how the two groups are represented.
Picturing Data: Making Line Graphs
A line graph shows a continuous relationship (trend) between two variables. Ordered pairs are plotted as points and then connected. Line graphs display all numerical data because both independent and dependent variables are measurements. Look at the following data table and graph.
As mentioned in the previous section, multiple line graphs are used when the dependent variable has more than one group or category. A key or legend should be used to show how the two groups are represented.
Picturing Data: Making Circle Graphs
Data Organization Practice
Let's practice what you have learned about data organization.
Read the lab scenario below, and then answer the questions that follow.
Dalton wanted to be able to grow the best strawberries in his garden. Dalton thought that fertilizer would help, so he decided to investigate the effects of different concentrations of Great Grow Fertilizer on the growth of strawberry plants.
Dalton hypothesized that if plants received a higher concentration of Great Grow Fertilizer, the plants would exhibit greater growth. He went to the plant nursery and purchased four flats of strawberry plants to use in his experiment. Each flat had five strawberry plants. Dalton applied Great Grow Fertilizer to the flats in the following concentrations:
Flat A 0% fertilizer
Flat B 5% fertilizer
Flat C 10% fertilizer
Flat D 15% fertilizer
After growing the plants for 30 days, Dalton recorded the height of the plants (cm). Dalton recorded his data as follows:
Flat A 15, 15, 14, 17, 18
Flat B 14, 19, 20, 18, 19
Flat C 10, 12, 10, 8, 10
Flat D 8, 5, 6, 6, 4
Design a data table to display Dalton’s data.
Create a graph using the mean (average) of data Dalton collected.