Complete the sentence.
A piece of pear turning brown is a ().

 - chemical change
 - physical change
A piece of a pear turning brown is a chemical change. The substances in the pear react with oxygen in the air and turn into a different type of matter.
If you scrape off the brown part of the pear, the inside will still be white. The inside hasn't touched the air. So the chemical change hasn't happened to that part of the pear.