Bell Ringers for Conservation of Mass

bell ringer 1

This is my first year of using Modeling InstructionTM in my chemistry classes. During a fit of productivity, I created some bell ringers for unit one, which is partly about conservation of mass. I hope you will find them useful. 

If you are logged in, you can access the bell ringers below. They are part of the "student document".



law of conservation of matter

Conservation of mass

Time required: 

Approximately 5 minutes per class period.


These are bell ringers for use while teaching conservation of mass.


Provide one bell ringer per day to get class started. Project it for students and give them just a few minutes to complete. 




I created these myself while using Modeling InstructionTM.


Students who demonstrate understanding can use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

*More information about all DCI for HS-PS1 can be found at and further resources at


Students who demonstrate understanding can use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.

Assessment Boundary:

Assessment does not include complex chemical reactions.


Emphasis is on using mathematical ideas to communicate the proportional relationships between masses of atoms in the reactants and the products, and the translation of these relationships to the macroscopic scale using the mole as the conversion from the atomic to the macroscopic scale. Emphasis is on assessing students’ use of mathematical thinking and not on memorization and rote application of problem - solving techniques.

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Comments 6

Hal Harris's picture
Hal Harris | Thu, 03/03/2016 - 11:07

Once your students are thoroughly convinced that mass is conserved, do the following demos on consecutive days:

1. Mix vinegar with sodium bicarbonate. [weight decreases; mass is conserved]

2. Mix vinegar with sodium bicarbonate inside a sealed baggie. [weight decreases; mass is conserved]

3. Mix vinegar with sodium bicarbonate inside a sealed bottle. [weight is conserved; mass is conserved]

Discuss all three of these observations only after the third one is completed.  

Chris Leverington | Thu, 08/16/2018 - 11:56

I'm gonna try using a couple of these over the next few days and I was wondering....Did you ever make a bell ringer for heating a metal?   Like the burning steel wool lab?  I would love one like that.  Maybe heating a piece of copper wire?  I don't think I have the capabilities to make such neat pictures as you have.  LOL.

Chad Husting's picture
Chad Husting | Sun, 08/19/2018 - 15:06

I like the idea.  I have a question.  Are you heating the copper or burning the copper?  There is a big difference.  I see that  there are "particulate drawings" of the copper.  Should there be some for oxygen?  Also, this might be hard to describe, but I was told by a professor to draw the object, like a piece of metal and then to draw a "magnifying glass" showing the particulate level.  I can completely understand what you are trying to do but students might get an unintentional misconception about the size of atoms.  I hope this helps and makes sense.  I really like your idea and want to encourage you to keep going.  Please continue to share.  I have a question. What program do you use to draw these?   It looks great.  Thanks again for sharing.

Chris Leverington | Tue, 08/21/2018 - 14:21

These bell ringers are generally aligned with the 6 mass labs that are done at the start of the Modeling Chemistry Curriculum.  Before I gave them this one we had done a lab where they measured the mass of a piece of steel wool and then burned it with a bunsen burner and measured the mass after.  The steel wool, much to the surprise of the students had gained mass, because as we know it had reacted with the oxygen in the air.   So this is designed to reinforce the idea that when a metal is burned that it will react with "air particles" and increase in mass.   We've also already discussed that we're zooming in on the particles, and that we're not drawing actual size.  The focus here is more on the number of particles vs the size of particles etc.  I don't do the whole magnifying glass thing because (1) you wouldn't be able to see the particles with the magnifying glass and (2) its just a lot of busy work.   At this point, I intentionally didn't draw the oxygen particles on the beginning side.  But when we discussed it as a class after they completed it, we discussed if we should have drawn them on the first box as well.

Honestly, I made them using the snipping tool and word.  I snipped her balances from the original document.  Put a new text box over her balance with the mass in it.  Created the particles with word.  Found a picture of a bunsen burner on google and snipped it, etc.    

Doug Ragan's picture
Doug Ragan | Thu, 08/23/2018 - 21:30

These would be great with the Classkick app that I use that allows the students to draw on their iPads.  Thanks for taking the time to put these together.  Will you have your students test these....?