Math Background

Lesson: Measurement
Introducing the Concept

Developing children's measurement skills is an ongoing task. Children are learning not only how to measure correctly, but also which units are used to measure various things. They learn how to measure length and height using inches, feet, centimeters, and meters.

Materials: overhead projector, transparency of a rectangle shape, paper clips of various sizes for each child

Preparation: Have enough bags of large and small paper clips for each child or group of children. Be sure to have the clips sorted by size. (Children will be using the clips to measure things.) Prepare a transparency of a rectangle that is shaped like the children's desks.

Prerequisite Skills and Background: Children should have a general understanding of how to measure the length of an object by lining up paper clips end to end.

Begin by passing out bags of paper clips to each child or group of children.

  • Say: Today we are going to talk about measuring things. We are going to measure many things in this room by using the paper clips that I just gave you. You'll see how long or tall these things are. Please empty the paper clips onto your desk.
  • Say: Now take some of these paper clips and put them together in a row, end to end, like this.
    On the overhead, model how to line up the paper clips.
  • Say: When we measure things, we put the edge of the first paper clip at the edge of the object we are measuring. Then line up the end of the next paper clip with the edge of the first paper clip.
    On the overhead, line a few paper clips along the edge of the rectangle on the transparency.
    6 paperclips stacked vertically
  • Say: Now I see how many clips there are from one end of the shape to the other. Let's count.
    Answers will vary, depending on the length of the paper clips used.
  • Say: Now use your paper clips to measure the length of your desk. Remember to line up the first paper clip and the edge of the desk.
    Circulate to see that children are lining up their paper clips correctly.
  • Ask: Who can tell me how long your desktop is in paper clips?
    Answers will vary. On the board, make a chart of five or so responses for the children to see the results.
    chart for paperclips
  • Say: This is interesting. We all have the same desktop, but we have different answers for the number of clips that were needed.
  • Ask: Why, do you think, did we get these different answers?
    Lead children to see that not everyone has the same size paper clips. Some might have smaller ones; some might have large ones. The lengths of the paper clips differed. Although the answers were all different, they could all be correct because the unit of measure was different. Some children may note that perhaps they were not precise enough while measuring.
  • Ask: What could we do to make sure that everyone got the same measurement?
    Lead children to decide that everyone should use the same size paper clips when they are measuring. That way, everyone should get the same result.
  • Say: Let's all use the large paper clips and measure the length of our desktops again.
    Have children measure their desktops again, this time with every child using the large paper clips.
  • Ask: Who can tell me the number of clips needed to measure the desktop this time?
    Ask several children and list their responses on the chalkboard. Answers should be within one paper clip of each other.
  • Ask: Is it better to measure using units of the same size or of different sizes?
    Children should respond that it is better to use the same size units.
  • Say: Let's try measuring other items with the same size clips. Let's use our small clips to measure the length of your math book.
  • Ask: Measuring in small clips, how long is your math book?
    Answers will vary, but they should all be close.

    Repeat this process with various items in the classroom, changing from large to small paper clips.

Houghton Mifflin Math Grade 2