Teaching a Physical and Chemical Change Unit

How to teach chemical and physical changes

Are you frustrated with finding different ways to get your students to understand how matter changes? Identifying differences between chemical and physical changes can be frustrating for both the teacher and the student. When I first began teaching, this was a unit I dreaded. I felt intimidated about accurately teaching this concept to my students and didn’t feel confident in myself. Flash forward ELEVEN YEARS, and I can now say this is one of my favorite teaching units. While teaching is still challenging, you’ll feel like a rockstar when students have grasped this difficult concept. Have that same rockstar feeling by learning tips and strategies to teach your students a physical and chemical changes unit. 

What is a change in matter?

It is essential to know the difference between the two ways that matter can change.

 
Physical Change: Changes the appearance of matter but does NOT create a new substance. Ex. Changes in the size, shape, or state of matter.
 
 
Chemical Change: A change that creates a new substance. 
 
 
Teach students that there are four ways to identify when matter undergoes a chemical change.

When teaching about color changes to identify a chemical change, you need to differentiate between adding colors such as food coloring or color being produced, like when leaves change color in the fall. Leaves are no longer receiving something they need, which is why they change color. Mold is another example of a chemical change. Part of the bread changes color because of something new on the bread, the mold. This is important to allow students to understand.

Referencing physical and chemical changes

Aside from anchor charts displayed around my classroom, we also read science texts and go over numerous examples to identify the differences between the two changes. Again, repetition and review are necessary to help students remember and apply their learning. 

Students learn best through hands-on learning. Therefore, your chemical and physical changes can include a variety of demonstrations, hands-on experiments, and lab activities. 
 
Before starting an activity in the classroom, I make sure my classroom is stocked with these low-cost, budget-friendly supplies. Having these in the classroom allows me to quickly gather materials needed to complete any activity to provide students with engaging lessons. 
 

Making claims

         Claim: A chemical change occurred.
 
         Evidence: A chemical change occurred because when baking soda and vinegar combined, carbon dioxide bubbles formed. These bubbles are a new substance which means a chemical change occurred.
 
This method allows me to help out my ELA counterparts while quickly assessing my science students’ ability to distinguish between a physical and chemical change.

Hands-on Experiments

Check out this video that I made that shows the different experiments that I use with my students. Watch it here
 
Experiments that you can use to teach physical and chemical changes include: 
  • Naked Eggs
  • Elephant’s Toothpaste
  • Race of the Ice Cubes
  • Air balloons – baking soda and vinegar using a balloon (as seen in the picture below)
  • Rates of rotting apples
  • Digestion in a bag
  • Tarnished coins
If time allows, keep hitting home these concepts to fit other learning modalities. Other activities you can use are:
Sketch Note Graphic Organizers:
To review the characteristics and examples of changes in matter, graphic organizers can help students brainstorm and organize their thinking without getting bogged down with writing. 
 
If your students can sketch things on their own, let them go for it. If they need more guidance, I create a graphic organizer that reviews all the unit concepts with my students.
 
These physical and chemical changes graphic organizers are great reference sheets to keep in binders to study or refer back to. In addition, you can easily make your own by putting concepts relating to physical changes on one side of the sheet and ideas related to chemical changes on the back.
 
Students fill in what they know. I allow my students to refer to their notes to help and then color them in. The coloring will enable them to use both sides of their brain, which means they are making deeper connections as they are working.  

Real-life scenarios:

         Bringing science into the real world is a big push for me this year. Immerse students in the thought that science is truly all around us. I do this by giving students different scenarios of matter changes that happen and asking them to identify the change. Add a crime fighter spin to it, and students are in love.
 
You can easily do this by creating 10-15 scenarios of physical and chemical changes around us. Students use the clues to determine which type of matter change it is. Once they identify the change, they need to include supporting evidence. Place your scenarios around the room so that students can get up and move as they work. Allows students to work together to help reinforce learning from one another. 
 
No time to create your own scenarios? 
 
 
Check out ones that are already created for you! This activity is editable, which allows you to personalize it to fit your classroom needs.

Flipbook:

         This is an excellent independent activity. Students can use their notes and reference sheets to fill in the information needed. There is a rubric included to allow you to grade this if you choose. If you are on a budget, fold a few sheets of paper together, have students answer a different question on each. Typically, I ask students to 
·      Identify a physical change
·      Examples of a physical change
·      Identify a chemical change
·      Examples of a chemical change
 
 

Assessments:

         You’re almost done with your physical and chemical changes unit! Now you need a final assessment. While I have given students tests before, I try to move to more authentic ways to show me what they know. My favorite is my project-based assessment. This chemical and physical changes project-based assessment is effortless to set up. 
 
Project: Students will demonstrate either a physical or chemical change to the class. During their demonstration, they will summarize what they are doing. They will identify which type of change occurred and explain why it is that type.
 
         To help struggling learners, it is helpful to include examples of physical and chemical changes that they can choose from and welcome students to develop their ideas. For my classes, I ask students to run their ideas by me first. Then, students are assessed on their classroom demonstration and knowledge of science.
 
In the past few years, students have been shy about presenting to the class. However, I allow my students to create a Flipgrid video that can be shared with the class. This will enable students to focus on the project and not on how it is presented to their peers.
 
If you would like more information on how to implement this quickly, click here.

         I hope these tips help you in your classroom. This unit can be confusing at first glance, but I hope these strategies and ideas will help make it much clearer.

Still have questions? Let me know by leaving them in the comments below. Looking for some materials to teach this unit, join my email list to help get you started! 

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