`Data SamplingDebra Dortch                   Henry Suder Elementary                               2022 West Washington                               Chicago, IL  60602                               (312)534-7864      Objectives: Students will be introduced to data sampling.Students will turn the data collected into useful information, make graphs  and use the graphs to solve problems.Materials needed:600 mL of soil for each groupuncooked twist macaroni (worms)dried lima beans (seeds)small rockslarge sealable plastic bagsmeasuring cupsnewspaperrulersbalance scalesStrategy:Divide the class into four groups.  Give each group, except one, a soil mixture of 600 mL of soil, 15 lima beans, 150 mL of rocks and 75 mL twist macaroni.  The other group will get the same soil mixture, except use 150 mL twist macaroni instead of 75 mL macaroni.  Label each bag with a different letter corresponding to a different spot on a backyard map you have drawn on the board or overhead projector.  Do not tell which group has the bag with the most worms. Tell the class this story;  You love to fish and decide that you would like to take a few friends on a fishing trip on Saturday.  You will need a lot of worms (at least 50).  You will need to dig many holes in the backyard to find that many worms.  Your mother would rather you not dig so many holes in her yard.  You remember in science class that you learned about sampling.  You ask if you can dig just four holes and from these four holes you will examine the dirt and replace the soil.  By taking these four samples you can pick the best spot for worms.  Then you will need one large hole in that spot and you promise to fill it in again.  Your mother loves the idea and, thanks to science, your fishing trip is saved.       Pass out newspaper, bags of soil, measuring cups and maps of the backyard.  Have balance scales and rulers on a nearby table so the students can use these as part of the observations.  Share these predictions with the class by writing the results of the findings on the chalkboard.  Predict at this time which soil mixture will have the most worms. The students will complete a table and organize their data.  Pass out a data table with columns marked "number of worms", "number of rocks" and "number of seeds."  Label the rows of the table with the soil amount (75, 150, 300, 450and 600 mL).  Count only the contents of the 75, 300 and 600 mL sample and predict the contents of the remaining two.  Each child must replace each soil sample completely into the bag before taking the next measurement.  At no time should the entire contents of the bag be dumped onto the newspaper.  Only the measured amount needs to be poured out for counting.  Conclusion:Using the measured data, have students complete the table and predict the missing data.  Discuss these predictions and record them on the chalkboard or the overhead projector.  Draw three graphs using the soil measurements (x-axis), and the observed number of seeds, worms and rocks (y-axis).  One student from each group will graph his groups counting for each graph.  Compare the graphs with the tables.  The class can decide which soil mixture is worm rich by using the graphs and the tables. Evaluation:Post activity discussion can focus on some of these questions:1) Which method of prediction was easier, using the tables or graphs?2) Can you name four ways in which we observed the soil?3) Can you name other ways in which data collection can be used in real life?References:Reeling in Data Samples, Janis Lange and Stephanie Williamson                             March 1990  Science and Children`