MS-PS1-5
The standard
Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.
Next Generation Science Standards
What this standard means
Students need to model a chemical reaction at the particle level. They should show that atoms rearrange to make new substances, but no atoms appear or disappear. They can use beads, cards, drawings, or a simple digital model to track each atom before and after a reaction.
Mastery looks like a model with the same number of each type of atom on both sides, plus a clear explanation of why total mass stays the same. Students often get stuck thinking products are “made from nothing,” gases vanish, or a new substance means new atoms were created.
Ways to teach it
- Use colored beads to model vinegar and baking soda reacting, then have students rearrange the same beads into product molecules.
- Ask students to explain why a sealed bag reaction keeps the same mass even when it looks very different afterward.
- Give a before-and-after atom diagram and ask students to circle any missing or extra atoms in two minutes.
- Connect to cooking by modeling how atoms in batter rearrange during baking, while the matter is still accounted for.
Plan a lesson for MS-PS1-5
Generate a complete lesson plan aligned to this standard, with objectives, activities, and materials. Free, no account needed.
Related standards
- 5-PS1-2
Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight...
- HS-PS1-7
Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
- HS-PS2-2
Use mathematical representations to support the claim that the total momentum of a system of objects is conserved when there is no net force on the system.
- HS-PS1-4
Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.