Summer Research Program for Science Teachers

 

 

 

 

Fady Ishak 

Legacy High School, Manhattan

August 2003

 

 

 

How to identify a physical change from a chemical change

 

 

 

Topic: Chemical and physical changes

 

 

Standards: S1a: demonstrates an understanding of the structure of atoms.

                    S4a: demonstrates an understanding of big ideas and unifying concepts.

                    S5b: uses concepts from science standards 1 to 4 to explain a variety of 

                            observations and phenomena.

                    S6e: recognizes and limits sources of bias in data.

                    S5f: works individually and in teams to collect and share information and

                            ideas.

 

 

 

Materials: hood, beakers, flasks, CuSO4, sugar, dil. HCl , water.

 

 

Learning objectives:

The students will be able to:

1- identify the difference between some physical and chemical properties

2- compare some physical and chemical changes.

 

Vocabulary:

chemical property, physical property, chemical change, physical change.

 

Do now:

Using your textbook, define the following terms:

chemical property, chemical change, physical property, physical change.

 

Motivation:

1- Ask the students to put on the board several characteristics to identify a person:

color, weight, height, shape...

2-  Show the students a burning match and ask them to write in their journals their observations.

 

Procedure:

Ask the students : what is the difference between the two cases?

Studentsí answers should imply that the height or shape of a person is a property that is not changed, while burning the head of a match  will change it to a new substance.

 

Mini lab: ( group work)

Divide the class into 4 groups:

two groups will add and dissolve blue CuSO4 to water, the other two groups

will add a little of diluted hydrochloric acid to granulated sugar inside the hood.

Using the jigsaw model, every group will share the results with the other groups.

What are some examples of physical and chemical changes?

Students will answer these questions in pairs:

Which of the following is a physical or a chemical change?

1- a candle burning

2- a soda bottle fizzes when you open it

3- hair curls as a result of a perm

4- holes appear in a worn-out shoe sole.

 

Summary:

1- What is the difference between physical and chemical properties?

2- What is a physical and a chemical change?

 

Homework:

Classify each of the following as a physical or chemical property or change:

1- metals have a shiny luster

2- milk turns spur if left outside the fridge

3- diamonds are hard

4- bread dough can rise.

 

Follow up:

 

Students will design an experiment to distinguish between a physical or a chemical property of their choice.

 

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