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Teaching a Physical and Chemical Change Unit

How to teach chemical and physical changes

Are you frustrated with finding ways to get your students to understand how matter changes? Identifying differences between chemical and physical changes can frustrate 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 over 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 no longer receive what 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 carbon dioxide bubbles formed when baking soda and vinegar combined. 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 physical and chemical change.

Hands-on Experiments

Check out this video that shows the different experiments I use with my students. Watch it here
 
  • 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
  • Pumpkin Science
If time allows, keep hitting home these concepts to fit other learning modalities. Other activities you can use are:
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
 
 
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.
 

Real-life scenarios:

         This year, bringing science into the real world is a big push for me. Immerse students in the thought that science is genuinely all around us. I do this by giving students different scenarios of matter changes that happen and asking them to identify the difference. 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 difference, they need to include supporting evidence. Place your scenarios around the room so 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 the ones that are already created for you! This editable activity 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. A rubric is included to allow you to grade this if you choose. If you are on a budget, fold a few sheets of paper together, and have students answer a different question.
 
Typically, on separate pieces of paper, students are asked to 
·      Identify a physical and chemical change
·      Present examples of physical and chemical changes
 
 

Assessments:

         You’re almost done with your physical and chemical changes unit! Now you need a final assessment. While I have given students tests, I try to move to more authentic ways to show them 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.
 
         It is helpful to assist struggling learners by including 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.
 
Students have been shy about presenting to the class in the past few years. 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 want more information on implementing 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.

 

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