Measurement
Lessons in this chapter
About Measurement
How Long? How Heavy? How Much? is measurement before measuring: kids compare objects directly, which is the idea units are invented to make easier.
Compare Length of Objects by Sight has kids line two things up and say which is longer. The rule they have to learn is that the comparison only works if both objects start from the same point, which is the same rule that makes a ruler work and is far easier to understand with two pencils on a table.
Find Which is Heavier and Which Holds More covers weight and capacity together, and both have to be felt rather than seen. A big empty box is lighter than a small full one, which is the first time kids hit the fact that size and weight are not the same thing.
No numbers appear in this chapter, and that is deliberate. A child who has compared things directly understands what a unit is for when 1st grade introduces one, instead of treating centimeters as an arbitrary rule to follow.
The two lessons, Compare Length of Objects by Sight and Find Which is Heavier and Which Holds More, open as worksheets in the page. No numbers appear in them, so each question asks a child to choose between two objects and nothing more. Both are free and scored as you go.
Frequently asked questions
Two lessons. Compare Length of Objects by Sight asks which of two things is longer or taller, and Find Which is Heavier and Which Holds More does the same for weight and for how much a container holds. No rulers or scales are involved. In the Common Core this is Measurement and Data (K.MD), which asks kindergarteners to describe and compare measurable attributes before they measure anything.
Because units only make sense once a child has compared things directly. Comparing two pencils teaches what longer means. A ruler then becomes a way of doing that comparison without the second pencil, which is the point of 1st grade's measurement work.
How to compare two objects and say which is longer, heavier or holds more, and to line things up fairly before judging length.
Because if one object starts further along, the longer one can look shorter. Starting both at the same point is the rule, and it is the same reason a ruler starts at zero.
By holding one object in each hand. It is less precise than a scale and that is fine. The judgement, this one is heavier, is what the lesson is after.
Which container holds more. Pouring from one to the other and seeing whether it overflows or leaves a gap is how kids test it.