Activity 6. Your younger sibling is studying chemical and physical changes in school and is having a hard time with the concept. You decide to help giving the youngster more examples that he or she would understand.
Using example not used in class, list and describe 7 physical and 7 chemical changes that a 3 rd grader would understand. End of Activity! Student Resource Booklet for:. Does it Matter? Grade 8. Phases of Matter. All material objects are either solid, liquid or gas. All matter is made up of molecules. These vibrate vigorously at a certain distance from each other, determined by their internal energy.
Temperature determines the phase state of the material. On the North and South Poles water freezes, forming large ice continents solid. At the equator water evaporates rapidly into water vapor gas. Temperature is a measure of the average speed of molecules. The amount of heat energy present determines their speed. The more heat available, the faster the molecules will vibrate and the more separated they become from each other.
In truth, matter has four phases. Iodine is an example of a substance that sublimes, as well as solid carbon dioxide dry ice , snow, and ice. Deposition occurs when a gas changes into a solid without passing through the liquid state. What are some examples of changes of state? Chemistry Phases of Matter Changes of State. May 23, Related questions How can changes of state be explained by the particle theory? How do changes in state involve exchanges of energy?
How do changes of state establish equilibrium? How do changes of state relate to the kinetic theory? How do the laws of conservation apply to changes of state? What changes in state are endothermic? Chemists learn a lot about the nature of matter by studying the changes that matter can undergo. Chemists make a distinction between two different types of changes that they study - physical changes and chemical changes. Physical changes are changes in which no bonds are broken or formed.
This means that the same types of compounds or elements that were there at the beginning of the change are there at the end of the change. Because the ending materials are the same as the beginning materials, the properties such as color, boiling point, etc will also be the same.
Physical changes involve moving molecules around, but not changing them. Some types of physical changes include:. As an ice cube melts, its shape changes as it acquires the ability to flow. However, its composition does not change. Melting is an example of a physical change. A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not.
When we heat the liquid water, it changes to water vapor. But even though the physical properties have changed, the molecules are exactly the same as before.
We still have each water molecule containing two hydrogen atoms and one oxygen atom covalently bonded. When you have a jar containing a mixture of pennies and nickels and you sort the mixture so that you have one pile of pennies and another pile of nickels, you have not altered the identity of either the pennies or the nickels - you've merely separated them into two groups.
This would be an example of a physical change. Similarly, if you have a piece of paper, you don't change it into something other than a piece of paper by ripping it up. What was paper before you started tearing is still paper when you're done.
Again, this is an example of a physical change. Image used with permission Public Domain; Moussa. Physical changes can further be classified as reversible or irreversible. The melted ice cube may be refrozen, so melting is a reversible physical change.
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