Unit Plan 18 (Grade K Math): Longer/Shorter & Heavier/Lighter

Focus: Describe and directly compare length and weight using informal tools; use precise words (longer/shorter, heavier/lighter, same).

Grade Level: K

Subject Area: Mathematics (Measurement & Data)

Total Unit Duration: 5 sessions (one week), 30–40 minutes per session

I. Introduction

Students explore measurable attributes by talking about and comparing objects’ length and weight. They practice direct comparison (lining up ends; using a balance scale to compare weight) and explain their decisions with precise language.

Essential Questions

• Which attribute am I comparing—length or weight?
• How do I know which object is longer/shorter or heavier/lighter?
• How do tools like a straightedge, string, or balance scale help me compare?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Name and describe the attributes length and weight for familiar objects.
2. Directly compare two objects for length by aligning endpoints; tell which is longer/shorter or the same length.
3. Directly compare two objects for weight by hefting and with a balance scale; tell which is heavier/lighter or the same weight.
4. Use precise words and simple records (labels, arrows, photos) to communicate comparisons.

Standards Alignment — CCSS Kindergarten (threaded across the unit)

• K.MD.1: Describe measurable attributes of objects (e.g., length, weight); describe several attributes of a single object.
• K.MD.2: Directly compare two objects with a common attribute; say which has “more/less” of the attribute (e.g., longer/shorter, heavier/lighter).
• Mathematical Practices: MP.6 (precision) emphasized; MP.2, MP.5 threaded.

Success Criteria — Student Language

• I can tell whether I’m talking about length or weight.
• I can line up ends to compare length and use a balance scale to compare weight.
• I can say and show which is longer/shorter, heavier/lighter, or the same.