Classroom activity Grade 4 Math
Vellacourt Elementary's Leak Patrol: Timing Drips at School
A grade 4 station activity where teams count drips for one minute, time a cup filling, and convert minutes to seconds to size up a school's slow leaks.
Objectives
- Students will count drips over a one-minute interval and record the count.
- Students will convert a time given in minutes into seconds using the relationship 1 minute equals 60 seconds.
- Students will compare their own drip count against a stated once-per-second rate and explain the comparison.
Vocabulary
Key words: leak, drip, interval, second, conservation
Teacher overview
The fictional Vellacourt Elementary asks its fourth graders to run a leak patrol each fall, checking the sinks and drinking fountains that staff have reported as slow drippers. This is a four-station rotation for teams of three students. At each station a bottle with a pinhole in the cap stands over a tray and drips into a marked cup, standing in for a leaking faucet, and each team counts drips for exactly one minute and times how long the cup takes to reach the fill line. Counting at the stations turns a slow drip, which can look like very little water, into a number the team can record, convert, and compare against a known rate. The counts and times belong to the team that measured them, so results will differ from station to station, and only the conversion items have one correct answer.
Activity Directions
Before class, set up four dripping stations, numbered 1 to 4, around the room. At each one, punch a pinhole in a bottle cap and poke a second small hole in the bottom of the bottle, which faces up once the bottle is turned over, so air can enter and the drip stays steady. Fill the bottle with water, and stand it upside down in a bottle holder or tape it to the edge of a shelf so it drips into a clear cup sitting in a tray. Draw a fill line partway up each cup with a marker. Vary the pinhole size so the four stations drip at noticeably different speeds, and test each station once before class.
Take 5 minutes to group students into teams of three and assign roles: a counter who watches the drips, a timekeeper who runs the stopwatch and calls start and stop, and a recorder who writes on the handout. Roles rotate at each station.
Spend 5 minutes modeling one count at the front of the room. Start a stopwatch, count drips aloud with the class for 30 seconds, and ask students what number they would expect for a full minute if the dripping stayed steady.
Run four rounds of 5 minutes each. At each station the timekeeper calls start, the counter counts drips for one full minute, and the recorder writes the count. The team then watches the cup and records how long it takes for the water to reach the fill line, in minutes and seconds.
Call time at the end of each round and have teams rotate to the next station in numerical order. Teams at Station 4 rotate back to Station 1.
The activity ends after every team has visited all four stations, which takes 20 minutes of rotation. Teams return to their seats and blot up any spills.
Give teams 5 minutes to finish the handout, using their recorded counts rather than starting a new count.
Close with a 5-minute debrief. Ask each team to report its fastest station's drip count for one minute, list the numbers on the board, and then have three teams read aloud the sentence they wrote for handout item 10. Close by noting that a slow drip adds up to a large volume over the course of a year.
Student Handout
Write your own team's counts and times. Your numbers will not match other teams, and that is expected.
Complete the last row of this table.
Minutes Seconds 1 60 3 180 5 300 10 Count the drips at your station for 1 minute. Write the number of drips.
Suppose your station keeps dripping at the same speed. How many drips would fall in 2 minutes?
The Environmental Protection Agency (EPA) says a faucet that drips once every second can waste more than 3,000 gallons of water in a year. How many drips is once every second in 1 minute?
Compare your count from question 2 with your answer to question 4. Is your station dripping faster or slower than once every second?
Watch the cup at your station. How many minutes and seconds did the drips take to reach the fill line?
Write your time from question 6 using only seconds.
Your team watched this station for 3 minutes in all. How many seconds is 3 minutes?
How many drips would a faucet that drips once every second make in 5 minutes?
Write one sentence you would say to the school custodian about the leak your team studied.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
Answer: 600 seconds.
One minute is 60 seconds, so 10 minutes is 10 times 60, which is 600 seconds. The earlier rows of the table show the same pattern.Answer: Accept any counted number of drips.
The count depends on the station's pinhole. Check that the student wrote a whole number and that the timekeeper ran a full minute rather than stopping early.Answer: Accept the question 2 count multiplied by 2.
A team that counted 44 drips should write 88 drips. Check the doubling rather than the size of the number.Answer: 60 drips.
There are 60 seconds in one minute, so one drip in each second gives 60 drips in a minute.Answer: Accept faster or slower, matching the team's own count.
A count above 60 drips means the station drips faster than once every second, and a count below 60 means slower. Ask students to name both numbers in their answer.Answer: Accept any timed result in minutes and seconds.
Check that the student wrote both a minutes figure and a seconds figure, and that the seconds figure is less than 60.Answer: Accept the question 6 time converted to seconds.
A team that wrote 2 minutes 20 seconds should write 140 seconds, since 2 times 60 is 120 and 120 plus 20 is 140.Answer: 180 seconds.
Three minutes is 3 times 60 seconds, which is 180 seconds.Answer: 300 drips.
One drip each second for 5 minutes is 5 times 60, which is 300 drips.Answer: Accept any clear, polite sentence naming the leak and a number.
Strong answers give the station or fixture and the drip count for one minute, such as a report that the sink dripped 44 times in a minute and should be looked at, rather than a general remark that water is being wasted.
Differentiation
Support (below grade level)
Give these teams a station with a slow, easy-to-count drip and a printed strip showing 1 minute next to 60 seconds. Provide a tally chart with boxes grouped in fives so counting does not depend on holding a running number in memory. Let a partner call out each drip while the student marks the tally. Reduce the assignment to questions 1, 2, 4, and 8.
Extension (above grade level)
Ask these teams to rank all four stations from slowest to fastest using their one-minute counts, then figure out how many drips the fastest station would produce during a full 6-hour school day, showing the conversion from hours to minutes first. They can also write a short recommendation naming which station the fictional Vellacourt custodian should repair first and why.
ELL supports
Pre-teach "drip," "leak," and "fill line" with a labeled drawing showing a faucet, a falling drop, a cup, and a marked line partway up the cup. Post the drawing at every station. Provide sentence frames for questions 5 and 10: "My station drips ___ than once every second because I counted ___ drips," and "The sink at ___ drips ___ times in one minute, so it needs ___."
Extensions
Teams can repeat the count at a real classroom sink that a custodian has identified as a slow dripper, then compare that count against the bottle stations. A class that wants a longer arc can keep a leak log for two weeks, recording each reported drip and whether it was fixed, and present the log to school staff along with the count that made the strongest case.