We can tell when matter is a liquid because liquids:• Do not keep their own shape; they take theshape of the container they are in.
And...liquids flow or pour. Oil being poured on a salad
Then what about sand,sugar and salt? Don’tthey pour, flow andtake the shape of thecontainer they are in?
If you magnifysand or sugar,you can seethat they arenot liquids.Sand, salt, andsugar are madeup of very smallparticles thathave a definiteshape .
Then there is that third state of matter: gasChild blowingair (a gas) intoa balloon.
A balloon or a bubble are justcontainers that hold a gas. For usthat gas is usually air.
There are other gases besidesthose in air. These balloonscontain a gas called helium whichis lighter than air.
Air, like all gases,takes the shape ofits containerand expands to fillits container.
Most gases including the gases inair are invisible—you simply cannotseem them. A jar of air
However, you do know air is therewhen it moves things such as thiswindmill. Wind—moving air– causes this windmill to rotate.
Or when you use the gas in yourlungs to blow out a candle.
But air is not one gas; it isa mixture of manydifferent gases—mainlynitrogen and oxygen plusa little carbon dioxide,argon and water vapor.
This pie chart shows the many gases thatgo together to make up air.
Gases are hard to observebecause remember, we said thatmost are invisible.Most gases have no color, notaste, no smell and you cannotfeel them unless they move.
Because all these gases are invisible wecannot tell one from the other just bylooking at them or smelling them. Jar of Jar of Jar of carbon nitrogen oxygen dioxide
But they are all very different gases.If you did not have any oxygen for more than afew minutes you would die!Oxygen is also needed for things to burn.Without oxygen nothing burns.Without the very tiny bit of carbon dioxidein the air, there would be no green plants.Plants use carbon dioxide to make food.Although most of air is nitrogen, nitrogen gasdoesn’t do very much all.
Things burn much more quickly in pureoxygen than in air. Air contains about 20percent oxygen.Velcro burning in air Velcro with puresmokes and smells but oxygen erupts indoesn’t burn much, flame.because air is only 20percent oxygen.
Another common gas is CarbonDioxide. We learned in the lastslide that Oxygen is necessaryfor things to burn. CarbonDioxide, on the other hand, putsfire out.
Carbon dioxide gas reacts with a substance calledbromophenolblue changing it from a blue color toyellow. To show that your breath has Carbondioxide, blow into a bromophenol solution. Students exhaled through a straw into the bromophenol blue. The carbon dioxide in their breath changed the color to yellow.
Making carbon dioxide in a ziploc bagTeachers, creating Carbon Dioxide in the ziploc bag allows students to see that there issomething there pushing the sides of the bag out. The gas fills its container and takes theshape of its container, and it is invisible. If you insert a burning match or glowing splintinto the bag, students will see that this gas puts fire out.
Later on you will learn that movement of the tiny particles that make up matterdetermines if the matter is a solid, a liquid or a gas.Particles Particles Particlesin a solid in a liquid in a gas
Can you name the three states ofmatter?Can you tell the differencebetween these three states? Bubbles hold an invisible gas called water vapor
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