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Quiz & test questions Grade 5 Science

Grazebrook's Salty Well: A Grade 5 Matter and Water Test

A 22-point end-of-unit test on dissolving, weight conservation, and mixing, set at a fictional town whose well water tastes salty, with twelve mixed-format items.

Objectives

  1. Students will explain what happens to a solid when it dissolves in water.
  2. Students will use measured weights to show that matter is conserved when substances dissolve or evaporate.
  3. Students will identify evidence that mixing two substances produced a new substance.

Vocabulary

Key words: dissolve, evaporate, conserved, solid, evidence

Teacher overview

This end-of-unit test is worth 22 points and covers dissolving, conservation of weight, and evidence that a new substance has formed. It mixes three multiple-choice items, five computation items, and four short-answer items, and every item is set at the fictional town of Grazebrook, whose well water tastes salty. The misconception the test is written to catch is the belief that dissolved salt is gone. Students who hold it tend to miss items 1, 5, and 9, and to answer item 2 as though the weight drops when salt dissolves.

Grazebrook's Salty Well: A Grade 5 Matter and Water Test — Grade 5 Science
Name: ____________________________ Date: ______________

Assessment

  1. A spoonful of salt is stirred into a glass of water until no grains can be seen. What best explains where the salt went? (1 point)
    A. It turned into water.
    B. It broke into pieces too small to see and spread through the water.
    C. It sank to the bottom and stopped existing.
    D. It floated out of the glass as steam.
  2. A student stirs 15 grams of salt into 200 grams of water. Nothing spills. What is the total weight of the salty water? (1 point)
    A. 185 grams
    B. 200 grams
    C. 215 grams
    D. There is no way to tell.
  3. A beaker holds 250 grams of water. A student stirs in 20 grams of drink mix, and all of it dissolves. What is the total weight of the beaker's contents now? Show your work. (2 points)
  4. A pan holds 300 grams of salty water from the Grazebrook well. The pan sits in a sunny window until all the water is gone. A white solid weighing 9 grams is left in the pan. How many grams of water left the pan? (2 points)
  5. Explain how the 9 grams of white solid left in that pan shows that the salt was in the water the whole time. (2 points)
  6. Two clear liquids are poured together, and a white solid appears in the cup. Which is the best evidence that a new substance formed? (1 point)
    A. The mixture got colder.
    B. A white solid appeared that was in neither liquid before.
    C. The liquid still looks wet.
    D. The cup felt heavier when it was picked up.
  7. An operator at the Grazebrook plant stirs a powder into cloudy well water. Small clumps form and sink to the bottom of the jar. Is that a sign that a new substance formed? Explain your answer. (2 points)
  8. A test jar holds 500 milliliters of well water. The operator pours 120 milliliters off the top for a test. How many milliliters are left in the jar? (2 points)
  9. A filter takes the sand out of Grazebrook's well water, but the water still tastes salty after filtering. Explain why the filter cannot take out the salt. (2 points)
  10. Describe two different ways a student could find out whether a clear glass of water has anything dissolved in it. Explain what each way would show. (3 points)
  11. Three samples of Grazebrook well water were dried in pans. Each sample started as 100 grams of water. Sample 1 left 2 grams of solid, Sample 2 left 7 grams of solid, and Sample 3 left 4 grams of solid. Which sample had the most dissolved matter in it? (2 points)
  12. Sample 1 left 2 grams of solid, Sample 2 left 7 grams, and Sample 3 left 4 grams. How many more grams of solid were left by the sample with the most than by the sample with the least? (2 points)

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: B. The salt broke into pieces too small to see and spread through the water. Choice A is wrong because salt does not become water, and choices C and D describe the salt leaving, which it did not.
  2. Answer: 215 grams. Choice C is correct because the salt is still in the glass after it dissolves, so the weights add: 15 + 200 = 215 grams.
  3. Answer: 270 grams. Add the weight of the water and the weight of the drink mix: 250 + 20 = 270 grams. Award 1 point for the correct sum and 1 point for showing the addition.
  4. Answer: 291 grams. The water that left is the starting weight minus the solid left behind: 300 - 9 = 291 grams.
  5. Answer: The salt could not appear from nowhere, so the 9 grams of solid in the pan must have been in the water before, spread out in pieces too small to see. Evaporating the water left the salt behind where it could be weighed. Award 2 points for an answer that says the salt was present but too small to see.
  6. Answer: B. A solid that was in neither liquid before is evidence that the two liquids reacted to make something new. A change in temperature or weight alone does not show a new substance, and the mixture looking wet shows nothing.
  7. Answer: Accept "yes" or "not necessarily" with reasoning. Yes: clumps appeared that were not there before, which is a sign of a new substance. Not necessarily: the clumps could be the cloudy particles stuck together, or powder that did not dissolve. Award 1 point for a clear position and 1 point for evidence from the item.
  8. Answer: 380 milliliters. Subtract the amount poured off from the amount in the jar: 500 - 120 = 380 milliliters.
  9. Answer: The salt is dissolved, which means it is spread through the water in pieces far smaller than the openings in the filter. Sand grains are large enough to be trapped, so the filter catches sand and lets the salt pass through with the water.
  10. Answer: Any two workable methods, such as letting the water evaporate in a pan and looking for solid left behind, or weighing the water, drying it, and comparing the weights. A full answer explains what each method shows: solid left behind means something was dissolved, and a weight that does not drop all the way to zero means matter stayed in the pan. Award 1 point for each method and 1 point for the explanations. Do not credit tasting the water, which is not a safe way to test a sample.
  11. Answer: Sample 2. All three samples started with the same 100 grams of water, so the sample that left the most solid, 7 grams, held the most dissolved matter.
  12. Answer: 5 grams. The most was 7 grams and the least was 2 grams, so 7 - 2 = 5 grams more.

Differentiation

Support

Give these students a version with items 3, 4, 8, and 12 already set up as vertical equations with the numbers placed, and allow a calculator. Read items 5, 9, and 10 aloud, and accept a labeled drawing plus one sentence for item 10.

Extension

Ask these students to write one more test item about the fictional town of Grazebrook that would show whether a classmate understands conservation of weight, then supply the answer and the point value. Have them explain which wrong answer their item is designed to catch.

ELL supports

Provide a word bank with "dissolve," "evaporate," "solid," and "weight," each next to a small sketch. Allow students to answer items 5, 7, and 9 with a labeled diagram and a short phrase, and give the sentence frame "The salt is still there because ___" for item 5.

Extensions

After the test, have students dry a pan of tap water and a pan of bottled water side by side on a sunny windowsill for several days and compare what is left in each pan. The comparison gives a concrete follow-up to item 11 and shows that even water that looks perfectly clear can carry dissolved matter.