Measuring Capacity
Lessons in this chapter
About Measuring Capacity
Fill it Up gives capacity its units, milliliters and liters, after a year of comparing containers by pouring.
Measure Capacity Using Standard Units introduces the milliliter and the liter and the measuring jug that reads them. Capacity is the measurement kids find least intuitive, because a tall thin container and a short wide one can hold the same amount and nothing about looking at them says so.
Solve Applied Problems on Comparison and Addition and Subtraction of Capacity applies the arithmetic. As with mass, the sums are familiar and the work is in the reading, particularly keeping milliliters and liters from being added together.
Pouring between differently shaped containers is worth doing at home alongside this chapter. It is the only way to make it obvious that height is not capacity, and it is a misconception that otherwise survives for years.
Measure Capacity Using Standard Units and Solve Applied Problems on Comparison and Addition and Subtraction of Capacity are two lessons and two worksheets, worked in the page and marked as your child answers. The applied lesson is the one that turns a reading off a jug into math problems worth solving. Both are free to practice online.
Frequently asked questions
Measuring capacity in standard units, milliliters and liters, and then applied problems on comparing, adding and subtracting capacities. It mirrors the weight chapter on purpose, so the method transfers rather than being relearned. Capacity, like mass, is a 3rd grade target in the Common Core (3.MD); the 2nd grade measurement domain (2.MD) covers length, time, money and data.
Milliliters and liters, with 1000 milliliters in a liter.
How much a container can hold. It is measured by filling and reading a scale, not by looking at the container's size.
Because height is the most obvious difference. A tall thin glass and a short wide one can hold the same amount, and pouring between them is the only convincing demonstration.
A teaspoon is about 5 milliliters, a large bottle of water is about a liter. Those anchors catch answers that are far out.
The 3-digit addition and subtraction from earlier in the year, with the extra care that milliliters and liters cannot be added without converting.