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Worksheet Grade 2 Engineering & Design

Rockaway Pond's Muddy Water: A Filter Layer Worksheet

A grade 2 worksheet in which students compare test results from a cloth filter and a cloth-and-sand filter, subtract within 100, and pick the better design.

Objectives

  1. Students will compare two filter designs using clear scores, drip times, and cups caught.
  2. Students will add and subtract within 100 to find differences and totals in a test table.
  3. Students will name one change to a filter design and explain how the change would help.

Vocabulary

Key words: filter, layer, muddy, design, compare

Teacher overview

Two teams in the town of Rockaway carried muddy pond water back to the classroom and tested cup filters on it, one built from a single cloth and one built from a cloth with a layer of sand on top. This worksheet hands students the resulting record and asks them to read three different measures at once, because a real filter design gains on one measure while giving something up on another. The sand filter produced clearer water and also ran slower and delivered less of it, which is exactly the trade-off a plant operator manages. If students in your class run this test themselves, remind them that no filter built in a classroom makes water safe to drink, and that the filtered water goes down the sink at the end.

Rockaway Pond's Muddy Water: A Filter Layer Worksheet — Grade 2 Engineering & Design
Name: ____________________________ Date: ______________

Student Worksheet

Two teams at Rockaway Pond tested cup filters. The pond water was muddy. Filter A had one cloth. Filter B had a cloth and a layer of sand. A clear score of 4 means the water looked clearest. A score of 1 means it stayed muddy. Here is what the class wrote down.

Filter Layers Clear score Time to drip through Water caught
A cloth only 2 20 seconds 3 cups
B cloth and sand 4 45 seconds 2 cups
  1. Which filter had the higher clear score?
  2. How many points higher was Filter B's clear score than Filter A's?
  3. How many seconds longer did Filter B take to drip through?
  4. How many cups did the two filters catch in all?
  5. How many more cups did Filter A catch than Filter B?
  6. The class poured 6 cups of pond water into Filter A. Filter A caught 3 cups. How many cups did not come through?
  7. Sand is made of tiny bits packed close together. How does that help a filter catch mud?
  8. Filter B dripped for 45 seconds. Then it dripped for 30 more seconds. How many seconds is that in all?
  9. Which filter is better for cleaning muddy water? Use the clear scores to tell why.
  10. Name one change you would make to Filter A. Tell how the change would help.

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: Filter B. Its clear score of 4 is higher than Filter A's score of 2.
  2. Answer: 2 points. Subtract the two clear scores: 4 - 2 = 2.
  3. Answer: 25 seconds. Subtract the two drip times: 45 - 20 = 25.
  4. Answer: 5 cups. Add the two amounts caught: 3 + 2 = 5.
  5. Answer: 1 cup. Subtract the smaller amount from the larger: 3 - 2 = 1.
  6. Answer: 3 cups. Subtract what came through from what was poured in: 6 - 3 = 3.
  7. Answer: The tiny bits leave only small gaps, so mud gets caught between them while water slips through. Accept any answer describing small spaces, packed grains, or mud being held back.
  8. Answer: 75 seconds. Add the two times: 45 + 30 = 75.
  9. Answer: Filter B. Accept any answer naming Filter B and citing the clear scores, such as Filter B scoring 4 while Filter A scored only 2.
  10. Answer: Accept any change that adds material or slows the water, such as adding sand, adding a second cloth, or folding the cloth twice. A student who suggests a bigger cup should be asked what that changes about the mud, since size alone does not clean the water.

Differentiation

Support

Give these students the table cut into two strips, one per filter, so each comparison is made between two visible numbers rather than read out of a grid. Supply counters for items 2 through 6 and read items 7 and 10 aloud, accepting labeled drawings in place of sentences.

Extension

Ask these students to design a Filter C that they predict would score a 4 for clearness and still catch 3 cups, sketch its layers in order from top to bottom, and write two sentences explaining which measure they expect to improve and which they expect to stay the same.

ELL supports

Pre-teach filter, layer, muddy, and clear with two jars of water, one stirred with soil and one plain, kept side by side during the worksheet. Provide the frames "Filter ___ was clearer" and "I would add ___ because ___," and let students trace the table row with a finger while answering.

Extensions

Run the same two filters on classroom mud water so students can compare their own clear scores with Rockaway's, using a four-card clearness scale posted on the board. Groups can then rank three filter materials from best to worst for catching mud and post the ranking beside the science sink.