Lesson objective: Understand that length is a constant (static) attribute.

Students bring prior knowledge of attributes from describing and comparing measurable attributes. This prior knowledge is extended to an understanding that certain attributes do not change as positions change, and as students move and test various items around the classroom. A conceptual challenge students may encounter is when orientation is manipulated, the physical attributes of objects also change.

The concept is developed through work with measurement of pictures and real life objects, which allows students to experience manipulating objects, measuring their attributes, and the outcomes of those measurements.

This work helps students deepen their understanding of equivalence because the task allows them to see that a change in orientation does not equate to a change of an object's static attributes.

Students engage in Mathematical Practice 3 (Construct viable arguments and critique the reasoning of others) as they use mathematical language to justify their conclusions.

**Key vocabulary:**

- attribute
- change
- orientation
- position
- same

**Special materials needed:**

- various classroom objects
- table for recording