Scatter Plots
by Roger Maxey, roger.maxey@cpsb.org

Content Area(s)
Math
Science

Grade Level(s)
6, 7, 8, 

Overview
Students use handheld computers to record data and make journal entries. Students do three math/science activities and record results in spreadsheets on handhelds then sync to use Excel to graph data as scatter plots.

Software
MS Excel, Documents to Go

Technology
meter sticks, tape measures, rulers, thermometers, plastic cups, Life Saver candies,
hot and cold water.

Objectives
TLW:
1. Determine amount of time that it takes Lifesaver candies to dissolve in different temperatures of water.
2. Collect and graph data.
3. Analyze graph to determine if there is a positive, negative, or no relationship between the variables measured.

Procedures
Lesson opener: Have the students look at copies of the Michael Jackson picture. Get them to identify who the celebrity is. They need to figure out what is wrong with the picture. They need to figure out that the short guy has big feet and Michael Jackson (in the modified picture) has little feet. This is not what we expect. We can use mathematics to analyze data to determine relationships.
1. Tell students that they will be scientists today. They will be performing a scientific experiment and also measuring and gathering data. They will record the data gathered on spreadsheets created on handheld computers. They will sync their handhelds with a desktop computer and graph the resulting data to determine if a relationship exists between the items studied.
2. This lesson can be done as a whole group activity, but students will get more out of it if it is done in small groups. Divide the students into groups of four students. (See class management annex for suggestions.) Each group will be given three activities to complete. Remind them to be careful to take as accurate of readings as possible.
3. For best classroom management, either assign or let the group pick job assignments for each group member. Suggested jobs are:
 leader – leads group and keeps them on task
 facilitator – gathers materials for group and helps set up
 recorder – writes down results and worksheets and plots points on graphs
 reporter – reports results to class
4. Pass out the activity sheets and go over the directions for each activity before the groups get their materials. Demonstrate how to measure arm span.
5. Have the facilitator for each group get the materials and bring them back to the group. (It is best to have the needed materials already in boxes ready for the students to pick up.) Students need to start the lifesaver activity, activity one, first and do the other two activities while they are waiting for the lifesavers to dissolve. (You can discourage the students from eating the lifesavers for the activity and get better cooperation from the groups by promising lifesavers for the groups that stay on task and complete the activities.) Activity One can take up to 45 minutes for the Lifesaver in the coldest water to dissolve. By putting less ice you can speed up the activity.
6. Monitor groups to make sure they are not wasting too much time checking water temperatures, but are being sure to wait long enough to get the correct reading. Also monitor to assure that they are correctly recording their data on their handhelds and saving the spreadsheets.
7. As they complete Activity One have them check their predictions. Remind them that it is okay if they are wrong, because it is just a prediction or guess.
8. Once the groups are finished, gather the completed worksheets from each group. Have them return materials and clean up. Explain that the groups will share their results the next day. Review what they have done so far.
9. In advance select and train four “student experts” for the second day. Three need to be trained to use the Chart feature in Excel and how to open the spreadsheets after the handheld computer is synced.
10. On the second day, return the worksheets to the groups. Have the students sync their handhelds with a computer and open their spreadsheets and create a graph of their data as a scatter plot using the Chart feature in Excel. The “student experts” are there to help groups that are having problems. It would probably be better to show the spreadsheet data to the class on the computer screen and then demonstrate how easily the computer can create the scatter plots. That way they can see visually the power of the computer.
11. When all the data has been plotted and the groups have printed their scatter plots, display the scatter plots. Tell the students that these are called scatter plots. Ask why these might have gotten the name. Get the students to identify any tendency of the data to line up in a diagonal line going up to the right or down to the right. A scatter plot with data tending to line up in a more or less upward diagonal line shows a positive relationship. The graph of the arm span and foot length should show a positive relationship. A scatter plot that goes down diagonally shows a negative relationship. The temperature and dissolving time should show a negative relationship. The higher the water temperature, the shorter the dissolving time. The graph of the third activity should have points scattered at random. It should show that there is no relationship between the data.
12. Draw attention to the graphs done by the individual groups. Have them notice that with small samples it is often harder to determine a relationship exists. Scientists try to gather more data to determine if relationships exist between conditions.
13. Have students make journal entries describing the activities on their handheld computers and identifying what they learned from the lesson.
14. Have the students share in pairs, “Think, Pair, Share”, what they wrote in their journals. Then have some students volunteer to share their journal entries.
15. Close lesson by making sure that the students realize that the scatter plots reveal some important facts about the relationship of the data graphed. #1 random scattering indicates no relationship, #2 points lining up roughly in an upward diagonal indicate a positive relationship, & #3 points that roughly line up in a downward diagonal indicate a negative or inverse relationship. Additionally, graphing can be used as a tool to analyze data but small amounts of data can give a false indication of a relationship or lack of.

Other Supporting Material
Activity%20One%20worksheet
Activity%20Two%20worksheet
Activity%20Three%20worksheet

Submitted on: 11/28/2004 6:26:51 PM