Posted: January 24, 2010
Estimated Time60+ minutes
To be used for any collection of numbers (polls, laboratory results, frequency, etc...) I had my students do an inquiry-based activity/laboratory "How Many Drops of Water Fit on a Penny". To do this, they were given only a simple task, "to use a dropper and water to see how many drops of water will fit on the surface of the penny before it spills over". From there, students were asked to log their number of drops. Students shared their results and we put on data table and calculated the range, mean, median and mode using all compiled student data. Students were also asked to place their number of drops on a yellow Post-it® Note and place it on a number line that was displayed on the wall in class (10-150 with 10 unit increments). We then had a discussion on why the range of numbers were so large and brainstormed ideas on how this range could be adjusted (to be made smaller) NOTE: to lessen the number of variables (size of drop, height of water, pressure on bulb, age of penny, location of drop etc...). The number line with Post-it Notes not only gave a students a visual of the range of data but confirmed the calculations of mean, median, and mode with the use of the Post-it Notes. (Note: students were asked to stack Post-it Notes if there was more than one of the same data point on the number line. In other words, if 15 appeared 3 times, there were 3 Post-it Notes stacked one on top of another). This process visually and most obviously pointed out the mode as well as made it clear how median could be viewed readily. After two more trials of getting rid of variables and becoming more consistent with laboratory procedures, students were asked to put the class averages for trial 2 this time on a blue Post-it Note, and trial 3 on a bright pink Post-it Note. Each time as the Post-it Notes were placed on the number line, they were to cover any Post-it Note that was there before the next trial. This made it clear to see how results were becoming more consistent and the range becoming closer. It also showed that with trial 3 (bright pink), the Post-it Notes were now stacked higher and closer together (mode and mean) on a number line. After each student placed their 3 colored Post-it Notes on the number and after wrap up discussion, it was also noted and discussed with students that if the number line were rotated from a horizontal position to a vertical position, it became a bar graph. The Post-it Notes really served as a visual aid to help students understand the concepts of not only mean, median, mode, range and bar graph but it also helped in the process for students to set a "goal" in decreasing the range by focusing on decreasing variables in an experiment. It made what could be a confusing concept (filled with calculations and numbers) into a visual, fun, easier to understand activity...not to mention students LOVE getting out of their seats!!
How it Works
Step 1Using an eye dropper and a cup of water, find out how many drops of water fit on the surface of a penny without it spilling over. You will have 2 practices before "counting" the next set of data. NOTE: after each trial, wipe your penny dry.
Step 2Each student shares result with class as teacher posts data on data table by student number.
Step 3Students calculated range, mean, median and mode from results and are asked to put THEIR data number from trial 1 on a yellow Post-it Note and place it on the number line displayed on the class wall. NOTE: Post-it Notes to be stacked one over (not covering) the other if there is more than one data point.
Step 4Class discussion on trial 1 in regards to range and how it can be made \"smaller"\ (note: by decreasing variables such as height of drop, pressure on dropper, side of penny, age of penny etc..). Students agree on turning 1 variable into a constant, thus making trial 2 more consistent as far as procedures, in the hope of decreasing the range.
Step 5After Trial 2, students again share data, discuss range, put individual data on blue Post-it Note this time, post on number line, and again discuss further variables and come up with yet another one to remain constant (now 2 variables become 2 constants). Repeat for trial 3, however, data is now displayed on bright pink Post-it Notes.
Step 6All 3 colored Post-it Notes now displayed on number line (yellow=trial 1, blue=trial 2, bright pink=trial 3). Wrap up discussion on change in range as variables are eliminated and procedures become more consistent amongst participants. Mean, median and mode can also be visually confirmed with the number line Post-it Note data and also shows students how "easy" mean, median, mode can be when numbers are simple grouped. Students were also made aware that if a number line such as this is rotated from a horizontal to a vertical position, it can also serve as a bar graph.
Educational GoalVariables vs. Constants (how it affects data)
Supporting All LearnersVisual
**turning what could be a difficult concept (calculating tons of numbers to find mean, median,mode, range) into a visual, hands-
Lesson ExtensionsGiven more time, what do you think would happen if we continued to omit more variables? Did more trials?
AssignmentToo many variables = inconsistent data collection
Increasing trials = more consistent results
Brainstorming ways to improve the activity and
0out of 0found this story helpful.
Share this activity: