Gather all students in a group and complete a KWL Recording Chart about weight.
This establishes what students know and are curious about
knowing about weight. Use the guiding questions below to prompt
students’ thinking about measurement knowledge and skills.
Show students two objects of similar size. Ask them to predict
which object weighs more. Give individual students two objects (of
different weight), one in each hand and ask the student to share which
one weighs more and which one weighs less.
Encourage students to share how they determined which weighed
more and which weighed less. Guide them to use mathematical terms
connected with weight such as heavier and lighter and more or less.
Offer this opportunity to all students who wish to participate. Be sure
to have a large number of items available for students to hold and
weigh so that everyone has a turn. Blocks, cubes, cotton balls, links,
books, and vegetables work well.
After all students have “weighed” two objects using their
hands, ask “What are some other ways to determine the weight of an
object?” Record the students’ responses and post for future reference.
Next introduce a variety of scales for weighing objects (see the i-Plan
materials list for suggestions). Provide a demonstration on each type
of scale and then focus on the rocker balance. Using several examples,
demonstrate how to weigh objects using this scale and discuss with
students how they can tell which object weighs more (that side goes
down) and which object weighs less (that side goes up).
Divide the class into pairs and provide each set of students with a pan balance, several sets of objects to weigh, and the Heavier, Lighter Activity Sheet
Have students use the pan balance scales to weigh
pairs of objects and record their findings on the sheet provided.
Younger students should record using pictures and older students
using words. Encourage students to predict which object is heavier or
lighter before actually placing it on the scale. As students engage in
this activity, observe what students do and say and ask guiding
questions to help them focus on the important mathematical ideas of