Physical and Chemical Changes

Objective:  Students will attempt to distinguish between physical changes and chemical changes

Matter  Matter is everywhere.  Matter is anything that takes up space and has mass.  Matter is constantly experiencing both chemical and physical changes.

Physical Change  Physical changes occur when matter changes its property but not its chemical nature.  Physical property changes could include a change in: texture, shape, size, color, odor, volume, mass, weight, and density.

Physical Change

Chemical Change  Chemical changes are changes matter undergoes when it becomes new or different matter.  To identify a chemical change look for signs such as color change, bubbling and fizzing, light production, smoke, and presence of heat.

Chemical Change  A chemical change occurs when fireworks are used. Fireworks are made of metals such as magnesium and copper. These change chemically as they light up the sky.

Is it a chemical or physical change?  Sugar dissolving in tea Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Logs burning Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Breaking water up by separating it into hydrogen and oxygen Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Cutting paper Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Crushing an aspirin Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Metal rusting Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  Lighter fluid burning Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  An egg rotting Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Is it a chemical or physical change?  An egg breaking Chemical Change Physical Change

OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

Correct!

Writing Activity: Putting Physical Change and Chemical Change to the Test  A new super-hero and super-heroine have offered their assistance in solving one of four difficult problems. The super-hero is known as Physical Change Man. He not only has the ability to change his own shape, size, and physical state, but also anything that he touches.

Super-heroine:  The super-heroine is known as Chemical Change Woman. She not only has the ability to change her own body into completely new substances, but also anything she touches. You may call upon only one super-person to assist you in each situation. You must identify which super-person will help you and you have to describe how that super-individual will use his/her powers to solve your problem.

Putting Physical Change & Chemical Change to the Test! In your response you should:  1. Identify the super-hero(ine) you selected  2. Why they were chosen  3. How they used their powers (physical change or chemical change) to accomplish their task.  4. It is also important that the solution is realistic and will not bring harm to the individual they are helping or the surrounding environment.

Sample Situation: You have found yourself imprisoned in an iron cage!  Solution A – Chemical Change Woman would come to my rescue. She could cause the bars to rust which would produce a new substance that would weaken the iron making it easier to break and escape. There are iron things rusting and falling apart all of the time. The rust wouldn’t hurt me, nor would it cause problems in the environment.

Or….  Solution B – Physical Change Man would come to the rescue. He could bend the bars of the cage into different shapes which wouldn’t change the iron, but it would make it easy to escape.  The technology exists to change the shape of iron metal. Changing the shape wouldn’t hurt me or the environment.

 Situation #1- Your hands are tied behind your back and you’re about to be pushed off the bank into a deep pool of water!

Situation #2  Somewhere, out of the darkness, you are about to be attacked by a bear!

Situation #3  You have found yourself stranded in a wooded wilderness where the temperature will soon drop below freezing!

Situation #4  What first appeared to be just a gentle rain has turned into a hail storm!