Physical versus chemical changes cracked#
Physical versus chemical changes code#

Describe some of the chemical and physical properties of at least three of the substances in the examples listed in question 1.Ī physical characteristic of paper is that it is flexible, so it can be crumbled and bent, and yet it remains paper. Chemical properties of a substance describe how it can react with other substances. Physical properties of a substance can be observed without changing the chemical makeup of the substance, such as density. Every substance has physical and chemical properties. Sometimes chemical changes occur, and the products don’t appear to be different from the reactants.ĥ. You cann o t always s ee whether a change in matter has occurred. Can observation always tell you whether a change in matter has occurred? Discuss why or why not. Some common indicators of chemical changes include the production or consumption of heat or energy, changes in color and composition, the combustion of a substance and the formation of new solids or gases.Ĥ.

Phase changes - for example, when a solid becomes a liquid or a liquid becomes a gas - also indicate a physical change. Physical changes can be indicated by changes in a substance’s texture, shape, temperature or amount. Using the examples given, discuss what indicators you can use to determine whether a physical or chemical change has taken place. Chemical changes alter the chemical makeup of a substance, creating new substances when chemical bonds are broken and new chemical bonds form.ģ. Also, these changes are often reversible. The same substance is present before and after the physical change. Physical changes do not change the chemical composition of a substance. What happens to matter when it goes through a physical change? What about a chemical change? Using your answers, write your own definition of physical change and chemical change. The objects listed in the first example are going through physical changes, and the objects in the second set are going through chemical changes.Ģ. Look at the examples given below and discuss which group of examples you think show physical changes and which show chemical changes.Ĭrumbling paper, dissolving sugar, melting ice, bending a metal earring and diluting orange juice with waterĪ piece of paper burning, a car door rusting, food digesting, a banana ripening and a leaf photosynthesizing When matter goes through a change, the process is either classified as chemical or physical.

Physical versus chemical changes code#

A version of the article, “Chemists Crack the Code to Ancient Roman Concrete,” appears in the Februissue of Science News.ġ.

Physical versus chemical changes cracked#

Have students discuss the first set of questions with a partner, then read the Science News article “ These chemists cracked the code to long-lasting Roman concrete” and answer the second set of questions. Before beginning this work, students should understand that substances are made up of atoms, elements and molecules. While this demonstration shows a physical change, remind students that acids and enzymes help to further break down food which is a chemical change.This discussion activity can be used to help students better understand the difference between physical and chemical changes. Students should observe that the food in the bag that has muscle contractions will break down more than the other bag. Put the bags down, have students make observations, wait another five minutes and repeat. Often, this is a classroom demonstration, so I will call students up to squeeze the bag to resemble stomach muscles. Allow the bags to remain as they are.Īfter 5 minutes, mimic the stomach muscles moving to break down the food. For example, this experiment will mimic how the muscles of our bodies help to break down food in the human body to be digested.įill the same types of food inside each bag trying to keep them as similar as possible. Reinforce the concept that science happens in our bodies, including physical and chemical changes.