Comparing the Weight of a Golf Ball and a Ping Pong Ball

• Model language to use to describe attributes
• Provide opportunities for practice with direct and indirect comparison
  • Start with comparing only one attribute
  • Direct comparison - physically arrange objects so that key attributes are fairly aligned

• Asking children open-ended questions that elicit their solution-methods
• Modeling and using math language

What to Look for in This Clip:

Teachers can support students' early measurement skills by giving them opportunities to describe and compare mathematical attributes of objects and people. In this activity, the teacher provides children with an opportunity to practice a direct comparison of weight using a balance scale.

She starts the activity by presenting a golf ball and a ping pong ball and asks the students to consider which one is heavier. Before placing each ball on the scale, she models language used to describe attributes related to weight. She connects the word heavier to its meaning when she says, "When something is heavier it means that it weighs more." She then repeats the same process for the term lighter. These are both great examples of attending to and using math language like heavier, lighter, weight, more, and less.

Next, she provides students with an opportunity to practice a direct comparison of weight, saying, "We're going to compare them [the balls] with the balance." When the students accurately determine that the golf ball is heavier than the ping pong ball, the teacher asks an open-ended question to elicit children's solution method, "How do you know that?" This allows students to share their knowledge of how the scale works in making a direct comparison of weight.