Physical and Chemical Changes
Background Information & Activities

© 1999-2012 BrainPOP. All rights reserved.

Before beginning this topic, we highly recommend reviewing the movies Solids, Liquids, and Gases and Changing States of Matter for review. This movie will introduce physical and chemical changes of matter and explore different examples. We recommend pausing the movie and discussing scenes together and having children come up with their own examples.

Review with children that everything is made up of matter. Then point out different items and have children describe their properties. Remind children that a property is a trait that tells you something about the object. For example, clay is thick, brown, and soft. A physical change happens when matter changes size, shape, or form. You can make physical changes to clay by molding it into a pot or flattening it out. The substance is still clay—its shape is just different. The substance also has some of the same properties.

Brainstorm other physical changes together. How can you make physical changes to a piece of paper? You can rip it, cut out a shape, paint or color on it, or fold it in different ways. The paper might look different, but it is still paper. The substance itself did not change. When you add food coloring to water, the water goes through a physical change. It's still water, just a different color. It still has many of the same properties. When you break a glass vase, it goes through a physical change. It looks different, but it's still glass. Explain to children that when you freeze water, it goes through a physical change. It's still water, just in a different state. You can melt the ice and it will become water again. When a candle melts, the wax goes through a physical change. It is still made of the same substance, even though it is not a solid. When the wax cools down, it will harden again. Help children understand that in some cases, physical changes can be undone, or reversed.

Point out physical changes all around us. When we get a haircut, our hair goes through a physical change. When grass gets mowed, it goes through a physical change. When we paint walls, they go through a physical change, too. When rock gets weathered by wind, land goes through physical changes. You may want to watch the Slow Land Changes movie for extension.

Explain to children that after a substance goes through a chemical change, it becomes a different substance. The substance before and after a chemical change can have very different properties. For example, bread dough goes through a physical change after it is baked. The dough and the bread have very different properties. They look, smell, and taste different. Help children understand that chemical changes cannot be undone. You cannot turn bread back into dough! Explore other chemical changes together. For example, when milk sours, it goes through a chemical change. Sometimes you can smell and even see the difference. If you leave a slice of apple out, the nutrients will go through chemical changes and the apple will turn brown. When metals is exposed to air and water, the metal goes through a chemical change and rusts. When wood is burned, it goes through a chemical change that cannot be reversed. Help children understand that chemical changes happen all around us. When tree leaves change color in the fall, they are going through chemical changes. When flowers die, they also go through chemical changes.

There are no set rules on how to tell if something is a physical or chemical change. But, you can help children ask questions about the substance to make an educated decision. Did the substance's properties change drastically? Can the change be undone? Was heat needed to spark the change or was heat released during the change? Encourage children to think about the substance before and after the change. They can make inferences and use inquiry skills to explore and understand.

See more lesson plans and resources: BrainPOP Educators.

Physical and Chemical Changes Teacher Activities

© 1999-2012 BrainPOP. All rights reserved.

Paper

Give each student one or two pieces of scrap paper, newsprint, or pages from old magazines. Challenge them to work in groups to create as many physical changes for the paper as possible. They may want to tear, cut, or color on the piece of paper. They can crumble or even wet the paper too. Encourage students to be creative! Afterward, have each group share a few of their examples with the whole class. Then challenge the groups to think of how paper can go through chemical changes. They do not have to carry out the changes, only list their ideas. Have them share these with the class.

Baking Soda and Vinegar

Demonstrate a chemical change for the whole class. Have students observe baking soda and vinegar in their separate bowls and write down the properties. Then combine the two together in a large bowl. (Be sure students stand away from the bowl.) What happens? Have students take notes, draw pictures, or even take photos. Explain that when baking soda and vinegar are combined, they go through a chemical change. Bubbles form because a gas is released, which is a byproduct of the chemical change!

Physical and Chemical Changes Family Activities

© 1999-2012 BrainPOP. All rights reserved.

Science in the Kitchen

Cook with your child and explore science in the kitchen! As you cook a meal, ask your child to identify the type of change each food is undergoing. For example, when you chop vegetables, do they go through physical or chemical changes? Why? When you cook them, are they going through physical or chemical changes? Why? Have your child take notes as you cook together. He or she may want to draw pictures or take photos of ingredients before and after they are changed.

Nature Walk

Take a walk with your child around your community or at a park. Then point out all the physical and chemical changes that are happening around you! For example, you might study a dying plant and observe its brown leaves or wilted flowers. What type of change does a plant go through when it dies? You may want to study a crack in the sidewalk. What kind of change is that? Have your child write down what you see together on the walk and draw pictures or take photos. Why is land always changing? Discuss together.