Math problem set Grade 2 Math
Snow to Water at Frostpine Hollow: A Grade 2 Melting Depth Problem Set
Grade 2 students compare snow depth to melted water depth across three storms at Frostpine Hollow, adding and subtracting within 100 to measure this reversible change.
Objectives
- Students will subtract within 100 to compare snow depth to melted water depth.
- Students will add within 100 to find combined totals across multiple storms.
- Students will estimate a reasonable depth based on a pattern in given data.
Vocabulary
Key words: depth, melt, compare, estimate
Teacher overview
Frostpine Hollow (a fictional place used for this problem set) records both the snow depth and the melted water depth after every winter storm, giving students a concrete example of water changing from solid to liquid and back, a reversible change. A common misconception in this set is assuming that a foot of snow melts into about the same depth of water; every storm in this set shows the melted depth is much smaller than the snow depth, and problem 4 asks students to apply that pattern instead of guessing a number close to the snow depth.
Problems
- Storm 1 left 8 inches of snow at Frostpine Hollow. After it melted, the water left behind was 1 inch deep. How many inches less is the melted water than the snow?
- Storm 2 left 12 inches of snow, which melted down to 2 inches of water. How many inches less is the melted water than the snow?
- Which storm left more snow, Storm 1 or Storm 2? How many more inches?
- Storm 3 left 6 inches of snow. Based on the pattern from Storms 1 and 2, about how many inches deep do you think the melted water will be? Explain your reasoning.
- What is the total snow depth from Storms 1, 2, and 3 combined? (Use 6 inches for Storm 3.)
- What is the total melted water depth from Storms 1 and 2 combined?
- How many more inches of snow fell in Storm 2 than in Storm 3?
- A fourth storm brought 5 inches of plain rain, with no snow at all. What is the total depth of water from the melted snow of Storms 1 and 2 plus the rain?
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: 7 inches less. 8 minus 1 equals 7.
- Answer: 10 inches less. 12 minus 2 equals 10.
- Answer: Storm 2, by 4 inches. 12 minus 8 equals 4.
- Answer: About 1 inch (accept about 1 inch or a little less; 2 inches does not fit, because Storm 1 had more snow than Storm 3 and made only 1 inch of water). Storms 1 and 2 both melted down to a much smaller depth than the snow, so a smaller snowfall like Storm 3's 6 inches should melt down to only about 1 inch of water.
- Answer: 26 inches. 8 + 12 + 6 = 26.
- Answer: 3 inches. 1 + 2 = 3.
- Answer: 6 more inches. 12 minus 6 equals 6.
- Answer: 8 inches. 1 + 2 + 5 = 8.
Differentiation
Support
Provide a two-column chart (Snow depth / Water depth) with Storms 1 and 2 already filled in, so students only need to compute the "how many less" subtraction rather than organize the data themselves.
Extension
Ask students to design a Storm 5 with a snow depth of their choosing between 10 and 20 inches, predict a reasonable melted depth using the same pattern, and check that their prediction is much smaller than the snow depth.
ELL supports
Pre-teach "melt," "depth," and "compare" using a simple picture sequence (a snow pile, an arrow, then a small puddle). Allow problem 4's explanation to be given orally to a partner before writing a sentence.