Water for Schools
Menu

Lesson plan Grade 3 Science

Tallowbridge's Fish Count: A Grade 3 Water Cleanup Lesson

A 50-minute grade 3 lesson in which students graph fish counts from a fictional brook before and after a water reclamation plant opened, then write a claim.

Objectives

  1. Students will draw a scaled bar graph from a table of fish counts taken at three sites along one brook.
  2. Students will compare fish counts from before and after a cleanup and describe the change in numbers.
  3. Students will write a claim about the plant with two numbers from the data as evidence.

Vocabulary

Key words: used water, water reclamation plant, screen, settle, claim, evidence, scale

Teacher overview

In the fictional town of Tallowbridge, water that went down sinks, tubs, and drains once ran straight into Brackenmere Brook. Two years ago the town opened a water reclamation plant, where a bar screen catches trash, a quiet tank lets heavy grit settle out, and tiny living things eat what is left before the cleaned water returns to the brook. This lesson gives students an invented set of fish counts from three brook sites, collected before the plant opened and again this spring, and asks them to graph the counts and argue whether the plant helped. One idea worth naming early is that "cleaner water" can be heard as a claim about how the water looks, so the lesson returns students to the counted fish as the evidence.

Procedure

Hook (5 min): Ask students where the water goes after it drains from a classroom sink. Collect three or four answers on chart paper without correcting them. Then tell the class that in the town of Tallowbridge, that water used to run into a brook without any cleaning at all.

Direct instruction (12 min): Sketch the three plant steps on chart paper as you name them: the screen catches trash, the tank lets grit settle, and the tiny living things eat what is left. Explain that the plant is a solution to a problem, and that a solution can be judged by what happens to the plants and animals in the brook. Model reading one row of the handout table aloud, and model drawing one bar on graph paper using a scale where each square stands for 2 fish.

Guided practice (10 min): With the class, draw the Mill Road bar together. Ask how many squares tall the bar must be when 16 fish are counted and each square stands for 2 fish. Confirm the answer of 8 squares before students continue on their own.

Independent practice (15 min): Students complete the handout: they finish the bar graph, answer the number questions, and write their claim. Circulate and check that every bar uses the same scale.

Closure and formative check (8 min): Ask for a thumbs up from any student who can name one number that supports the claim that the plant helped the brook. If fewer than three quarters of the class put a thumb up, reread handout question 6 together and rebuild the total for both springs on chart paper before collecting the handouts.

Tallowbridge's Fish Count: A Grade 3 Water Cleanup Lesson — Grade 3 Science
Name: ____________________________ Date: ______________

Student Handout

Brackenmere Brook runs past the town of Tallowbridge. A volunteer crew counted the fish they saw in one hour at three sites. They counted two springs ago, before the water reclamation plant opened, and again this spring.

Site Fish counted two springs ago Fish counted this spring
Mill Road 4 16
Cedar Bend 6 24
Low Meadow 2 12

Draw a bar graph of this spring's counts. Let each square stand for 2 fish. Then answer the questions.

  1. Cedar Bend had 24 fish this spring. Each square stands for 2 fish. How many squares tall is the Cedar Bend bar?
  2. This spring Cedar Bend had 24 fish and Low Meadow had 12 fish. How many more fish were at Cedar Bend?
  3. Mill Road had 4 fish two springs ago and 16 fish this spring. How many more fish were there this spring?
  4. Add this spring's counts: 16 fish, 24 fish, and 12 fish. What is the total?
  5. Add the counts from two springs ago: 4 fish, 6 fish, and 2 fish. What is the total?
  6. This spring the three sites had 52 fish in all. Two springs ago they had 12 fish in all. How many more fish were counted this spring?
  7. Cedar Bend had 6 fish two springs ago and 24 fish this spring. This spring's count is how many times the old count?
  8. Did cleaning the used water help the fish in Brackenmere Brook? Write a claim in one sentence. Then give two numbers from the table as your evidence.

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: 12 squares. Each square stands for 2 fish, so 24 divided by 2 is 12 squares.
  2. Answer: 12 fish. 24 minus 12 is 12.
  3. Answer: 12 fish. 16 minus 4 is 12.
  4. Answer: 52 fish. 16 plus 24 is 40, and 40 plus 12 is 52.
  5. Answer: 12 fish. 4 plus 6 is 10, and 10 plus 2 is 12.
  6. Answer: 40 fish. 52 minus 12 is 40.
  7. Answer: 4 times. 24 divided by 6 is 4.
  8. Answer: Yes, the plant helped the fish. Accept any claim stating that the brook has more fish since the plant opened, supported by two numbers from the table. Strong responses cite the totals of 12 fish and 52 fish, or a single site such as Cedar Bend going from 6 fish to 24 fish. Do not accept a claim supported only by how the water looks, since the counts are the evidence the class collected.

Differentiation

Support

Give these students graph paper with the three site labels and the scale already printed along the side, keeping each square at 2 fish so their graph matches the Mill Road bar drawn with the class. Assign items 1 through 4 and item 8 only, and provide the sentence frame "The plant helped the brook because the count went from ___ fish to ___ fish."

Extension

Ask students to predict the count at a fourth site two miles downstream from the town of Tallowbridge and to explain what the crew would need to measure to check the prediction. Have them add the predicted bar to the graph in a different color and label it clearly as a prediction rather than a count.

ELL supports

Pre-teach "screen," "settle," and "count" by showing a kitchen strainer, a jar of stirred soil left to stand, and a tally chart. Pair each student with a partner for the graphing step, and allow item 8 to be answered orally or with the frame "More fish live in the brook now because ___."

Extensions

Invite the class to write three questions they would ask a wastewater treatment plant operator about the screen and the settling tank, then compare their questions with the plant steps drawn on chart paper during the lesson.