Texas TEKS 3.5.C

Science3rd GradeRecurring themes and concepts

The Standard

use scale, proportion, and quantity to describe, compare, or model different systems

Texas Essential Knowledge and Skills for Science

Teacher's field guide

What Students Need to Do: Students use measurements, counts, and relative size to compare systems. They read or make simple models and explain what was enlarged, reduced, or kept in proportion.
What Mastery Looks Like: Given two systems, the student measures or counts features and makes accurate comparisons using units and relative amounts. The student creates a labeled model with a clear key and explains which relationships stay consistent.
Common Misconceptions: Students may think a larger model always represents a larger real object. They may compare one quantity while ignoring the total, such as counting fish without considering tank size. They may also assume every model includes every feature or uses actual size.
How to Assess It: Exit ticket: Tank A has 3 fish in 6 liters, and Tank B has 6 fish in 12 liters. Draw each tank using one square for 2 liters, then compare size, fish quantity, and fish-to-water proportion.

Lesson moves

Build two playground models with linking cubes, using one cube for one meter, then compare area, equipment count, and spacing.
Discuss: How can a globe fit on a desk, and which size relationships between continents and oceans should stay the same?
Play Model Match by pairing system cards with scaled drawings, measurement keys, and quantity statements, then justify each match.
Use a weather map key to compare storm size, rainfall amounts, and each storm’s distance from your town.

Free download

A ready-to-print activity worksheet aligned to 3.5.C, with an answer key for the teacher on its own page. No account needed.

PDF, US Letter, prints cleanly in black and white.

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