An Elemental Understanding of Isotopes

Isotope eggs

In January of 2017, Chad Hustings wrote a blog post, Isotopes, Nuts, Bolts and Eggs, about an activity some colleagues and I had shared in a workshop at BCCE in 2016. With encouragement from many ChemEd X readers that wanted to try the activity for themselves, I am sharing more details and a student handout.

Chad wrote: 

Time required: 

About 30-40 minutes for the activity. This depends on how many balances are available to share and how many different isotopes are made for a single element. We had 5 balances for 12 or 13 teams of two students. Students can work in groups of 3 as well.

My First Lab of the Year

measuring volume and mass of water

My first experiment involves measuring the density of water. Each group of two kids is assigned a specific volume of water from 10 to 100 mLs on the tens. They simply measure the mass of an empty graduated cylinder and then add the water and find the mass again. Once they have their data they go around the room and find another group that has one of the volumes that they need and get the data from them and record their names. Once complete they generate a graph of the data and answer a few simple questions. The whole procedure can be completed in about 20 minutes.

Time required: 

10 minutes prep

20 minutes classtime

An Activity to Demonstrate the Principles of Chemical Kinetics and Equilibria

Example student graph

A classroom activity to demonstrate the principles of chemical kinetics and equilibria and the utility of the mole concept is described here. The activity involved no hazardous materials or complex equipment and can be enjoyed and appreciated by general studies students as well as chemistry majors.

Time required: 

30 - 45 minutes of class time


Build Your Own Hoffman Apparatus

DYI Hoffman Apparatus

Chad Hustings blogged this past school year about building his own Hoffman apparatus for each group of students. I have been using a Hoffman apparatus that had been purchased by my district before I began teaching there over 20 years ago to demonstrate electrolysis of water, but providing each student group with the ability to perform an electrolysis themselves is a powerful activity. I have used a different version of a homemade Hoffman apparatus, but after reading Chad's blog post, I decided to use a version close to his.  

Time required: 

If the Hoffman apparatus is built ahead of time (this takes about 5 minutes for each one if the teacher builds them), then the activity and discussion should take less than a 45 minute period.  

Soap Making

preview graphic of soap samples

My first year teaching chemistry, I was looking for a soap-making lab or activity that I could run in my chemistry class with 25-30 students working at the same time. I usually do this activity right before spring break, as it provides enough time for the soap to harden and cure (high school students are impatient to use their soaps right away, which you should not do with cold process soap). I have used the activity at different points in the curriculum: during intermolecular forces, during acids and bases, and during stoichiometry. Although I know teachers who use soap making as a project during their stoichiometry unit, I chose to not emphasize the calculations as it would require more time than I have available. Simply making the soap easily fits in a 45-minute period.

Time required: 

45 minutes to just make the soap. Discussion of key concepts may take another class period.