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Classroom activity Grade 5 Math

Barrowfen Plant Screen Log: A Grade 5 Line Plot Gallery Walk

A grade 5 gallery walk where teams read twelve daily screening weights posted around the room, build a line plot in eighths of a pound, and compare the days.

Objectives

  1. Students will record twelve measurements given in eighths of a pound and plot them on a line plot.
  2. Students will subtract two mixed numbers with eighths to compare the heaviest and lightest days.
  3. Students will add mixed numbers with eighths to find the total for a group of days.

Vocabulary

Bar screen
A bar screen is a row of metal bars at the entrance of a treatment plant that catches rags, sticks, trash, and other large debris out of incoming sewage. Keeping this junk out protects the pumps and machinery further along in the process.

Also: screenings, line plot, mixed number, eighth

Teacher overview

This is a whole-class gallery walk for teams of three, built around Barrowfen, a fictional town whose wastewater plant starts with a bar screen. A bar screen is a row of steel bars that catches rags, sticks, and wipes before the water reaches the pumps, and the crew empties it every morning and weighs what it caught. Twelve daily log cards are posted around the room, each showing one morning's weight in whole pounds and eighths, so teams collect the data by walking rather than by reading it off a page. Once every team has all twelve weights, the class turns the list into a line plot and uses the plot to compare days, which is the kind of comparison a plant supervisor makes when deciding whether the screen needs a second cleaning.

Activity Directions

  1. Before class, print and post twelve log cards spaced around the room. Card 1 reads 2 1/8 pounds. Card 2 reads 2 1/2 pounds. Card 3 reads 2 3/8 pounds. Card 4 reads 2 1/8 pounds. Card 5 reads 2 3/4 pounds. Card 6 reads 2 1/2 pounds. Card 7 reads 2 1/8 pounds. Card 8 reads 2 3/8 pounds. Card 9 reads 2 1/2 pounds. Card 10 reads 2 7/8 pounds. Card 11 reads 2 1/8 pounds. Card 12 reads 2 3/8 pounds.
  2. Introduce the setting (6 min): Explain what a bar screen catches and why the crew weighs it. Show the blank number line on the handout, which runs from 2 to 3 and is marked every eighth, and point out that every card will land on one of those marks.
  3. Gallery walk (14 min): Divide the class into teams of three and send each team to a different starting card. Teams copy the card number and the weight into the recording table on the handout, then move clockwise to the next card. Call a move every 70 seconds so that all twelve cards are visited.
  4. Build the line plot (8 min): Teams return to their seats and place one X above the matching mark on the number line for each of the twelve weights. Remind them that the total number of X marks must be twelve before they go on.
  5. Answer the questions (7 min): Students complete handout questions 1 through 8 using their own line plot, working alone but checking totals with their team.
  6. Debrief (5 min): Build the class line plot on chart paper by asking each team for the count above one mark, then ask two questions. First, which weight came up most often and what that tells the crew about a normal morning. Second, what the crew should check on the day that weighed 2 7/8 pounds, since that day sits farthest from the rest of the plot.
Barrowfen Plant Screen Log: A Grade 5 Line Plot Gallery Walk — Grade 5 Math
Name: ____________________________ Date: ______________

Student Handout

The crew at the Barrowfen plant weighs what the bar screen catches each morning. Copy each card's weight into the table, then mark each weight with an X on the number line. Use your line plot to answer the questions.

Checkpoint: after the walk, your table should show these twelve weights in pounds: 2 1/8, 2 1/2, 2 3/8, 2 1/8, 2 3/4, 2 1/2, 2 1/8, 2 3/8, 2 1/2, 2 7/8, 2 1/8, and 2 3/8. Fix your table before you plot.

  1. How many days weighed 2 1/8 pounds?
  2. What was the greatest weight on the plot?
  3. What was the least weight on the plot?
  4. What is the difference between the greatest weight and the least weight?
  5. How many days weighed more than 2 1/2 pounds?
  6. Two of the days weighed 2 1/8 pounds each. What do those two days weigh together?
  7. Card 5 weighed 2 3/4 pounds and Card 3 weighed 2 3/8 pounds. How much heavier was Card 5?
  8. Three of the days weighed 2 1/2 pounds each. What do those three days weigh together?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 4 days.
    Cards 1, 4, 7, and 11 each read 2 1/8 pounds, so four X marks sit above that spot on the plot.
  2. Answer: 2 7/8 pounds.
    Card 10 is the only weight above 2 3/4, and it sits at the far right of the plot.
  3. Answer: 2 1/8 pounds.
    No card reads less than 2 1/8, so that mark is the left end of the plot.
  4. Answer: 3/4 pound.
    Subtract 2 7/8 minus 2 1/8. The whole numbers cancel and 7/8 minus 1/8 = 6/8, which in lowest terms is 3/4 pound.
  5. Answer: 2 days.
    Only Card 5 at 2 3/4 pounds and Card 10 at 2 7/8 pounds sit to the right of 2 1/2 on the plot.
  6. Answer: 4 1/4 pounds.
    Add 2 1/8 plus 2 1/8. The whole numbers give 4 and the eighths give 2/8, so the total is 4 2/8, which in lowest terms is 4 1/4 pounds.
  7. Answer: 3/8 pound.
    Rename both weights in eighths: 2 3/4 is 2 6/8 and 2 3/8 stays 2 3/8. Then 6/8 minus 3/8 = 3/8 pound.
  8. Answer: 7 1/2 pounds.
    Three days at 2 1/2 pounds each give 2 1/2 plus 2 1/2 plus 2 1/2, which is 6 plus 3/2, or 7 1/2 pounds.

Differentiation

Support

Give these teams a handout whose number line already shows the first three X marks placed, and provide a fraction strip folded into eighths that students can hold against the line while they plot. Pair them with a team that finishes early for the counting steps, and allow them to answer questions 1 through 5 only, which use reading and counting rather than fraction operations.

Extension

Ask these students to write two new log cards that would raise the greatest weight on the plot to 3 1/8 pounds and leave the least weight unchanged, then explain how the difference between greatest and least changes. Have them redraw the plot with the two new cards included.

ELL supports

Post a labeled photo or drawing of a bar screen beside the first card, with the words "screen," "catch," "weigh," and "pound" written in English and, where possible, in students' home languages. Provide a sentence frame for the debrief: "Most mornings the screen caught about ___ pounds, so ___ pounds is not a normal morning."

Extensions

Have students weigh the classroom recycling bin each morning for two weeks, recording each weight to the nearest eighth of a pound, and build a line plot from their own data. Ask them to compare the shape of that plot with the Barrowfen plot and to write two sentences about what a day far from the rest of the marks might mean in each case.