Isotopes, Nuts, Bolts and Eggs

plastic egg atom models

What are we doing to help kids achieve?

 I am always searching for a good isotope activity that I can use with students. I want something that is quick, easy, effective and demonstrates the idea of isotopes and weighted average.  I have tried examples using “pre” and “post” 1982 pennies. The pre 1982 are pennies made of copper. Post 1982 pennies are zinc with copper coating.  There are activities where pre and post pennies can be analogous to an isotope. I have also attempted the same idea with peanut and plain chocolate covered candies that model isotopes. A hazard of that experiment is that the materials are sometimes eaten before the data is recorded.

I have finally found a nice little experiment thanks to the chemistry department at Delta College in Michigan.  Here is how the experiment works. First, I scrounged and found some really cheap plastic Easter eggs.  These represent the “isotopes”. It is helpful to have eggs that are the same color. Next, I went to a tractor and feed store and bought a couple hundred of the cheapest nuts that they had in the hardware section.  About half of these I painted black.  Each group of students then received a bag of about 10 “isotopes” (eggs) and were asked to measure the mass of each (the eggs were numbered for accounting purposes).  Students discovered that about six of the isotopes “eggs” were the same mass, two were lighter and two were heavier. They were asked to put these in groups, to choose one isotope or egg from each group and look inside. Each of the eggs (isotopes) had the same number of black nuts but different number of the silver or non painted nuts.

Now here is where the background information started to kick in. The black nuts were analogous to protons and the silver ones were analogous to neutrons. Students were even able to take the “average” masses a variety of ways and discovered that the weighted average was most similar to their data.

This is the first isotope activity I have tried where the students can look inside the model that resembled the atom and find information that reinforced what an isotope actually is. Furthermore, the quantitative data forced them to examine beliefs about different types of averages and what the numbers really mean. This took a bit to set up but was inexpensive and can be used year to year. Give it a try. Do you have an isotope activity that you like? Why not share in the comments below….

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Comments 7

Kyla Gurganus's picture
Kyla Gurganus | Sat, 09/16/2017 - 21:25

I've used the poker chips isotope activity, the CPO atom-building game, and isotope posters made with garage sale stickers, but I can't wait to try this Easter egg version!  I am a clearance shopper and got dozens of plastic Easter eggs on clearance for about 10 cents a dozen last year, so now I have use for them (other than Easter egg hunts)!

Deanna Cullen's picture
Deanna Cullen | Sat, 09/16/2017 - 22:05

Thanks for your interest! Please let us know how it works for you and your students! 

Dave Blackburn's picture
Dave Blackburn | Tue, 09/19/2017 - 10:14

You can also use nuts, bolts, and washers for the Law of Multiple Proportions - have the students build several BoNu2 and several BoNu3, then weigh the components. If anyone is interested I 'll post the handout I've used for that.

Caveat: Washers are not a standard thickness and you could get several "isotopes" in a batch, stamped from different gauges of sheet metal.

Bernadette Harkness's picture
Bernadette Harkness | Tue, 09/19/2017 - 13:15

Chad, thanks for attending our workshop at the 2016 BCCE and sharing on this site! We hope to share more at the next BCCE and welcome your feedback for how this worked out for your class. 

I agree with the Caveats as well, the precision in mass for the nuts, bolts and washers is variable depending upon your source. It is recommended that each piece comes from the same source (ie all washers from same lot etc) for an activity, otherwise the avg masses may give unintended (more complex) ratios or math scenarios.  

We also have nuts and bolts activities for Empirical Formula, Stoichiometry, Limiting Reactants and Indirect Analysis that really gives hands on learning in a similar way.

Chad Husting's picture
Chad Husting | Wed, 09/20/2017 - 07:32

Thanks.  If you would be willing to share, I would love to road test these.  I have found that kids really need and benefit from a kinestic hands on approach to make more sense of the math.  This is a struggle for my students.  Any help would be appreciated.  Thanks again.

Tressa Sharma | Mon, 09/25/2017 - 15:27

Thank you for sharing this! I love this idea to really help the kids get a more hands-on experience with a difficult topic.  I was wondering if you had a digital copy of the handout you use with this. I tried clicking on the link to the Delta College in Michigan but it didn't work.  Is there anything you could share?  Thank you!