Physical properties of matter..introduction (Teach)
Introduction to Physical Properties of MatterBy Moira Whitehouse, PhD
Properties of matter•are the characteristics of a substance that wecan observe such as its color and texture.
Properties of matter•are the characteristics of a substance thatyou can observe such as its color and texture.•are characteristics that can be observedusing our senses- sight, smell, touch andtaste.
Properties of matter•are the characteristics of a substance youcan observe such as its color and texture.•are characteristics that can be observedusing our senses-sight, smell, touch andtaste.•allow us to distinguish one substance from another.
Let’s look at some of the physicalproperties of two substances we allknow--sugar and sand.
Let’s look at some of the physicalproperties of two substances we all know--sugar and sand.The color of a substance is one of itsproperties that can be observed usingthe sense of sight.
Let’s look at the physical properties oftwo common substances we all know-sugar and sand.The color of a substance is one of itsproperties that can be observed usingthe sense of sight.On the next page you will see photosof sugar and sand. Look at themcarefully. What color are they? (bespecific)
If you were specific in your observations, youmight have said, “bright snow-white” for sugarand “tan” for sand. Color is one of theproperties which allows us to tell whichsubstance is sugar and which is sand.
Another property of a substance is itsodor. Anyone who has tried to smellsugar and sand knows that neither onehas much of an odor.
What about how it feels—its texture(another property). How does sugar feelwhen you rub it between your fingers?What about sand?
Most people say that both sugar andsand feel rough and grainy.
Other physical properties of a substanceinclude:•its state of matter at room temperature--whether it is a solid, liquid or gas•whether or not it is magnetic—attracted toa magnet•whether or not it floats or sinks in water•whether or not it dissolves in water•whether it conducts electricity, heat orsound
Let’s take a look at some of these physicalproperties of sugar and sand:•What state of matter is each substance at roomtemperature?•Does either sugar or sand dissolve in water?•Is either sugar or sand attracted to a magnet?•We will discuss what substances are conductors ofelectricity and heat in another presentation.
State of matter:What state of matter is sugar at roomtemperature? a. solid b. liquid c. gasWhat state of matter is sand at roomtemperature? a. solid b. liquid c. gas
Both sugar and sand are solids at roomtemperature.
Another physical property of a substance iswhether or not it is magnetic.
Ground up pieces of iron aremagnetic—attracted to a magnet.
What about sugar and sand. Is eitherattracted to a magnet? What do youpredict? Let’s try it.
What about sugar and sand. Is eithersugar or sand attracted to a magnet?What do you predict? Let’s try it. Sand
SandNeither sugar nor sand is magnetic. Themagnet does not pick up the tiny grains ofsugar or sand.
Solubility--whether or not a substancedissolves in water is another physicalproperty.
Solubility--whether or not a substancedissolves in water is another physicalproperty of substances.Dissolve means to mix evenly. When asolid dissolves in water, the molecules mixevenly and the solid seems to disappear.The resulting liquid is called a solution.When a substance dissolves, it may losesome of its physical properties such ascolor and feel.
•If we mix sugar and water and stir, whatdo you predict?a. The sugar will dissolve in waterb. The sugar will not dissolve in water
•What about if we mix sand and waterand stir?•What do you predict?a. Sand will dissolve in the waterb. Sand will not dissolve in the water
•Below are the photos of two containers, one with a mixtureof sugar and water and the other with a mixture of sand andwater.•Circle the photo of sugar and water, and check the one withsand and water.•Write “dissolved” under the correct photo.•Write “solution” under the correct photo.
Sugar mixesevenly with waterand dissolves.Sugar and watermixed togetherform a solution.
As long as we are shaking the sand and water,the two substances mix evenly. But as soonas we stop shaking the container, the sandsettles to the bottom of the flask. Sand doesnot dissolve in water.
Imagine that the molecules of water, sugar and sandhave been magnified so we can see them. Circle thediagram that shows molecules of sugar and water?Check the one that shows a mixture of molecules ofsand and water? Explain your choices.
When sugar is dissolved in water you cantell the sugar is still there, even though itbecomes invisible. How can you tellthat sugar is still there?
Aha, yes, you can use your sense of taste ortouch. When you take a solution of sugar andwater, it tastes sweet. Also, sugar water feelssticky. The sugar is still there. You just cannot seeit. When you mix sugar with water thesugarloses its white color and its grainy, rough
Yes, sugar dissolves in water along withother flavors and colors and produces asolution that tastes sweet.Sugar dissolved inwater makes the sweetflavor found in all kindsof soda pop.
Sugar mixed with many substances likecandiesorcookies tastes SWEET
Sand and sugar are easy to tellapart. When you look at them youcan immediately tell one from theother just by their most obviousphysical property—color. Butwhat about two substances thatlook alike, such as sugar and salt.They have many physicalproperties in common.
Both:•are snow white, have little or no smell,are solids at room temperature and feelrough and grainy.