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Lesson plan Grade 3 Math

Meadowlark Pump Station Timing: A Grade 3 Minutes Lesson

A 45-minute grade 3 lesson where students find elapsed time to the minute on a number line as pumps fill a tank at a fictional pump station.

Objectives

  1. Students will find elapsed time to the minute using a number line.
  2. Students will solve addition and subtraction word problems about time in minutes.

Vocabulary

Pump
A pump is a machine that adds energy to water to move it or push it uphill, doing the job gravity cannot do on its own. Water systems use many different kinds of pumps to move water from wells, through treatment, and out to customers.

Also: elapsed time, minute, number line

Teacher overview

Meadowlark Pump Station (a fictional pump station) runs electric pumps that push water uphill into a storage tank. Operators there time how long each pump runs, because a pump that runs too long or too short can be a sign of trouble. This lesson uses that timing job to teach elapsed time to the minute on a number line, a grade 3 measurement skill. A common misconception is that students count the clock numbers instead of the minutes between them; the number-line model in this lesson is built to correct that by labeling each hop with the number of minutes it covers.

Procedure

Hook (5 min): Show a photo or short clip of a pump running, and set a demonstration clock to 7:45. Tell students the pump stopped at 8:15 and ask, "How many minutes did it run?" Take a few guesses without confirming, then say the class will learn a way to be sure.

Direct instruction (12 min): Model the number-line method. Draw a line, mark 7:45 on the left, and count forward in friendly jumps: 15 minutes to 8:00, then 15 more minutes to 8:15, for 30 minutes in all. Do a second model that runs the other way: if a pump starts at 11:05 and runs 20 minutes, hop 20 minutes forward to land on 11:25. Emphasize that each hop is a number of minutes, not a clock number.

Guided practice (13 min): In pairs, students use a blank number line to solve two problems the teacher displays: a pump that runs from 6:20 to 6:55, and a pump that starts at 10:40 and runs 30 minutes. Circulate and check that pairs are counting minutes between marks. Ask two pairs to show their number lines to the class.

Independent practice (10 min): Students complete the Student Handout, questions 1 through 6, each on its own number line. These questions state their own start times and run times so students work them without the modeled examples.

Closure / exit ticket (5 min): Students answer one question on an index card: "A pump starts at 3:15 and runs 20 minutes. What time does it stop?" Collect and scan for 3:35 and for a correct number-line count before dismissal; if more than a third miss it, reteach the forward hop next day.

Meadowlark Pump Station Timing: A Grade 3 Minutes Lesson — Grade 3 Math
Name: ____________________________ Date: ______________

Student Handout

Use a number line for each question. All times are on the same day.

  1. Pump A starts at 8:20 and stops at 8:55. How many minutes did it run?
  2. Pump B starts at 9:10 and runs 25 minutes. What time does it stop?
  3. Pump C runs from 10:05 to 10:50. How many minutes is that?
  4. Pump A ran 35 minutes. Pump C ran 45 minutes. How many more minutes did Pump C run?
  5. A tank fills in 40 minutes. The pump has already run 25 minutes. How many more minutes until the tank is full?
  6. Two pumps run one after the other. The first runs 30 minutes. The second runs 20 minutes. How long is that in all?

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: 35 minutes. From 8:20, hop 10 minutes to 8:30, then 25 more minutes to 8:55, for 35 minutes in all.
  2. Answer: 9:35. From 9:10, hop 25 minutes forward: 20 minutes to 9:30, then 5 more to 9:35.
  3. Answer: 45 minutes. From 10:05, hop 45 minutes to reach 10:50.
  4. Answer: 10 minutes. 45 − 35 = 10 more minutes for Pump C.
  5. Answer: 15 minutes. 40 − 25 = 15 more minutes until the tank is full.
  6. Answer: 50 minutes. 30 + 20 = 50 minutes in all.

Differentiation

Support

Give students a pre-marked number line with every five-minute point labeled so they count in fives rather than ones. Pair the handout with a small clock manipulative students can turn to match each start and stop time before they place it on the number line.

Extension

Ask students to solve question 3 a second way by starting at 10:50 and hopping backward to 10:05, and to explain why both directions give 45 minutes. Have them write a two-pump problem where the total run time is exactly one hour.

ELL supports

Pre-teach "start," "stop," "elapsed," and "in all" with a labeled clock and a number line side by side. Provide the sentence frame "The pump ran ___ minutes because I hopped from ___ to ___." Allow students to show hops with arrows on the number line instead of writing sentences where the objective allows.