Physical and Chemical Changes

Introduction

What is the difference between a physical and chemical change? You will be an expert on both once you finish the activities throughout this webquest! Make sure you have a copy of the venn-diagram so that you can take notes on the differences and similarities between physical and chemical changes!

Task

Click on the link below so that you can see physical and chemical changes in action and decide which one is happening in each event!

http://www.glencoe.com/sites/common_assets/science/virtual_labs/E03/E03.html

After playing the game, you will have a brief idea of the differences of chemical and physical changes. Remember to fill out your venn-diagram as you go through all of these steps. You will need to document all of the things you learn about each one on the correct side! If you find any similarities of the two changes, you document those in the center circle on your venn-diagram! At the end, you will be able to use this organizer to help you answer some questions about what you learned!

Process

Chemical changes make new substances

Anytime a new substance is made, a chemical change takes place. Usually two or more materials are combined and a new substance is formed. A chemical change can produce amazing explosions, like fireworks. Some chemical changes are a little more difficult to spot, like when a nail rusts.

If you notice bubbles being formed, or a change in color or temperature, there is a good chance a chemical change has taken place, but not always. Scientists can determine if a chemical change has occurred by asking this question: Was the substance formed present before? If the answer is no, then it is a chemical change.

Since chemical changes make new substances, most of them cannot easily be undone. For example, when you burn wood, you can’t really turn the gases back into a log very easily.

Physical changes do not make a new substance.

Physical changes come in many forms. It can be a change in the shape or appearance of an object, like crumpling a piece of paper, or cutting, bending, or dissolving something.

Since objects do not become a different substance during a physical change, it is usually easy to reverse the change. For example, if you dissolve sugar in water you can easily reverse the change by evaporating the water from the solution. When all the water evaporates, sugar crystals will be left behind.

In order to learn more about chemical and physical changes click the link below! Watch the educational video about physical and chemical changes and then go to the test yourself button and answer the questions to see if you know the difference between the two changes!

http://studyjams.scholastic.com/studyjams/jams/science/matter/changes-of-matter.htm

Evaluation

Answer the questions below to test your new knowledge on physical and chemical changes!

Circle the correct answer to the next three questions.

Which of the following is an example of physical change?
1. Mixing baking soda and vinegar together, and this causes bubbles and foam.
2. A glass cup falls from the counter and shatters on the ground.
3. Lighting a piece of paper on fire and the paper burns up and leaves ashes.
4. Baking a birthday cake for your mother.
Which of the following is an example of chemical change?
1. Filling up a balloon with hot air.
2. Taking a glass of water and freezing it by placing it in the freezer.
3. A plant collecting sunlight and turning it into food.
4. Your dog ripping up your homework.
Which change can be easily be reversed?
1. Chemical Change
2. Physical Change
3. Both a physical and chemical change
4. Neither a physical or chemical change

Write T (True) or F (False) for the next two questions.

4. ___Changing the size and shapes of pieces of wood would be a chemical change.

5. ___In a physical change, the makeup of matter is changed.

Fill in the blank.

Chewing food to break it down into smaller particles represents a 6. _________ change, but the changing of starch into sugars by enzymes in the digestive system represents a 7. ___________change. Physical change can be the change of the 8. ____________ or 9. _________ of an object.

Write a short paragraph answering the following question.

10. Compare and contrast physical and chemical changes.