Instructional Video
PBS

Pbs: Odd Squad: Briefcase Balancing Act

K - 1st Standards
Learn about comparing weights with the Odd Squad. Olive and Otto are curious about what is inside Ms. O's briefcase and hope to guess what it is from its weight. They use a seesaw for a scale and common objects as weights for comparison.
Instructional Video
Khan Academy

Khan Academy: Order by Length

1st - 2nd Standards
Sal orders three objects by length, and compares the lengths of two objects indirectly by using a third object. [2:37]