Overview & Lesson Sequence

Focus on Standards & Assessment

Materials Needed, Preparation & Planning, Management Strategies

Background Info

Intro Activity
Why Study Populations?

Meet the Aphids

Research Project
Aphid Population Growth

Data Analysis I

Data Analysis II

Optional Activity
The Power of Exponential Growth

References

Glossary

Suppliers

Resource Sheets

Great Gravidity Home

CISEO Home

Data Analysis I

Materials Needed per group

• Data Collection Sheet
• Graph paper or computer
• spreadsheet software

Class Time Required
First week: Approximately 30 minutes

Weeks 2-3: Approximately 10 minutes for students to graph, analyze data and discuss in groups 20-25 minutes for sharing and discussing with entire class.

At the beginning or end of each week, use this activity to help students think about their data. At the end of the last week, the end of the research project, use Data Analysis II.

Students use the data they have been collecting to begin answering these questions: How does a population grow? What factors affect the growth rate of populations? Using this information, students can make predictions about what will happen during the next week, such as how fast the population will change. Data collected during the following week will provide information to confirm or refute their predictions.

Procedure
Each week of the observation and data collection, have students analyze their data. Data analysis can be completed manually or using a computer spreadsheet program such as Excel. Initially, discuss data display possibilities (charts, graphs) and how such a visual presentation improves analysis of data.

Check Students' Prior Knowledge
If you are not sure the extent to which your students know and understand graphs and graphical representations, show them several graphs ("USA Today" is a good source.) and ask them what the graphs tell them. Ask what kinds of data would be represented by pie charts, by bar graphs (comparing categorical data) and line graphs (change over time). For line graphs, ask what kinds of variables are on the X-axis, and on the Y-axis.

Have groups present their data displays, results and predictions to the class. Note differences in scale used for their line graphs and how the scale may affect data interpretation. Display the graphs for the whole class to compare.

Facilitate a whole group discussion about data and population rates. You might use the following questions to help students focus:

What does your graph tell you about your aphid population as it developed over the last week? (Answers will vary. Most likely the graphs will resemble a "J" shape; students should recognize that the graphs illustrate change over time.) Do you notice patterns in the graphs from different groups? (They should be similar initially, then there should be some differences based on how well the students care for the plants and aphids as well as other factors.)

You may want to lead a discussion on the different variables that affect the data. How would you explain differences in data among the groups, if there are differences? Predict what you think will happen to the population over the next week. Provide explanations for your predictions.

Have groups continue data collection and observation for the remainder of the project. Each week conduct a similar data analysis and discussion and have groups revisit their predictions. At the end of the data collection and observation period, conduct Data Analysis II.

Assessment
Review the representations of the data for clarity and accuracy. Note the extent to which students use evidence to support

observations and predictions. You may want to have them write individual responses in their science journals or notebooks and check them periodically.

Note
Students with more advanced mathematics skills may want to try using the equation described in the"Background Information -Mathematical Models," to predict numbers of individuals in their aphid populations. This exercise will provide an opportunity for students to see the connection between a mathematical expression and its graphic representation.