Fun Activities to Teach Physical and Chemical Changes

This is such an important concept but it can be tricky for the students to understand. As I have mentioned in previous posts, I believe constant reinforcement, using different resources, is the way to ensure student understanding. When it comes time to teach physical and chemical changes, I use several activities, to solidify the concepts, before I move on to my basic chemistry unit.

Without really teaching the concept too deeply yet, I dive into the unit by doing a demonstration. The students make a chart in their notebooks with the headings “physical change” or “chemical change”. I want them to try to decide what the differences are as they watch about 20 different actions that I demonstrate. 

It varies year to year, but I usually do:

• grinding chalk into dust
• food coloring in water
• salt in water
• burning a piece of paper
• burning a candle
• baking soda and vinegar
• lighting a match
• ripping paper
• oil and water
• eating
• breath on a mirror
• holding ice in my hand
• Alka Seltzer in water
• cornstarch in water
• baking soda on a cut lemon
• hold up a plant and ask it’s process
• wipe table with water and watch it “disappear”
• boil water

It takes quite a while to review each of the answers, which is already helping the students understand the difference between the two changes. I then give them the matching game cards to help reinforce the demonstration. Sometimes I add a timer to see how fast they can accurately match cards. 

Usually as a homework assignment, or during the following class, I have students read the informational passage and answer the questions.  This way I know that they are getting some text based information, to solidify the concept, since I don’t have good textbooks. 

For at least the next two to three class periods we do fourteen hands on mini lab stations. Students walk around with an observation chart to determine whether the outcome of their station activity is a physical or chemical change. 

I love hearing the buzz around the room as students are excited about doing the labs.  They sometimes argue about the results with their friends which is what I want to hear! I want to hear words like “it’s irreversible or reversible” and questions like “did it change states or not?” 

The nice thing about the physical and chemical stations lab is that I can discuss a lot of the chemical answers during my upcoming chemistry unit. Since we have iPads, I ask students to take five to ten second videos as they move around the stations. They put these in their digital notebooks, and we can easily refer back to them, as we move through the unit.

Those who follow me know that I am a big advocate of CER!  One of my activities I do with my class is to give them rather challenging images and have them work out whether it is a physical or chemical change. The tough part is that they need to support their decisions with either evidence that they’ve researched, or come up with themselves. Lately, I have been letting students work as partners to bounce ideas off each other. Getting students to write in science class is becoming more and more challenging, so this way they support each other. 

As a reinforcement activity, I have students read a story about kids that found an old warehouse to explore. As students move through the story, they pull out examples of both physical and chemical changes that the story mentions.  There is a chart for students to use to classify the discoveries. 

By the time we finish this mini unit, I feel like the students have a strong foundation for understanding more complex chemistry concepts. Referring back to the activities, as we get more complicated, is very useful. 

Please check out my chemistry unit, that I have put in two posts called, 7 Steps to Teaching Chemistry to Middle School Students and How to Cheaply Teach Chemical Reactions to Middle School.    All of the activities can be found in my Teachers Pay Teachers called Science by Sinai.