11. Then what about sand,
sugar and salt? Don’t
they pour, flow and
take the shape of the
container they are in?
12. If you magnify
sand or sugar,
you can see
that they are
not liquids.
Sand, salt, and
sugar are made
up of very small
particles that
have a definite
shape .
13. Then there is that third state of matter:
gas
Child blowing
air (a gas) into
a balloon.
14. A balloon or a bubble are just
containers that hold a gas. For us
that gas is usually air.
15. There are other gases besides
those in air. These balloons
contain a gas called helium which
is lighter than air.
16. Air, like all gases,
takes the shape of
its container
and expands to fill
its container.
17. Most gases including the gases in
air are invisible—you simply cannot
seem them.
A jar of air
18. However, you do know air is there
when it moves things such as this
windmill.
Wind—moving
air– causes this
windmill to
rotate.
19. Or when you use the gas in your
lungs to blow out a candle.
20. But air is not one gas; it is
a mixture of many
different gases—mainly
nitrogen and oxygen plus
a little carbon dioxide,
argon and water vapor.
21. This pie chart shows the many gases that
go together to make up air.
22. Gases are hard to observe
because remember, we said that
most are invisible.
Most gases have no color, no
taste, no smell and you cannot
feel them unless they move.
23. Because all these gases are invisible we
cannot tell one from the other just by
looking at them or smelling them.
Jar of Jar of Jar of
carbon nitrogen oxygen
dioxide
24. But they are all very different gases.
If you did not have any oxygen for more than a
few minutes you would die!
Oxygen is also needed for things to burn.
Without oxygen nothing burns.
Without the very tiny bit of carbon dioxide
in the air, there would be no green plants.
Plants use carbon dioxide to make food.
Although most of air is nitrogen, nitrogen gas
doesn’t do very much all.
25. Things burn much more quickly in pure
oxygen than in air. Air contains about 20
percent oxygen.
Velcro burning in air
Velcro with pure
smokes and smells but
oxygen erupts in
doesn’t burn much,
flame.
because air is only 20
percent oxygen.
26. Another common gas is Carbon
Dioxide. We learned in the last
slide that Oxygen is necessary
for things to burn. Carbon
Dioxide, on the other hand, puts
fire out.
27. Carbon dioxide gas reacts with a substance called
bromophenolblue changing it from a blue color to
yellow. To show that your breath has Carbon
dioxide, 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.
28. Making carbon dioxide
in a ziploc bag
Teachers, creating Carbon Dioxide in the ziploc bag allows students to see that there is
something there pushing the sides of the bag out. The gas fills its container and takes the
shape of its container, and it is invisible. If you insert a burning match or glowing splint
into the bag, students will see that this gas puts fire out.
29. Later on you will learn that movement of the tiny particles that make up matter
determines if the matter is a solid, a liquid or a gas.
Particles Particles Particles
in a solid in a liquid in a gas
30. Can you name the three states of
matter?
Can you tell the difference
between these three states?
Bubbles hold
an invisible
gas called
water vapor