|How does heat affect the volume of gas in a balloon?|
The volume of a gas is directly related to the
heat and pressure. If temperature increases,
volume increases. If pressure increases, volume
decreases. You can do an experiment for yourself:
take a balloon and put it in the freezer, if what
I said above is true, it should shrink, because it
If you are interested in the math, we describe
this relationship with the equation:
PV=nTR which means:
pressure x volume = amount of atoms x
temperature x a constant “R”
The constant R is just a number we add so that the
equation is actually equal.
Have you ever opened a warm soda and took a sip?
It probably didn’t taste very good, and one of the
reasons might be because it’s not very bubbly
anymore. To make a soda bubbly, the factory will
use a high-pressure tank to pump in lots and lots
of carbon dioxide (the same stuff that we
breathe). Then, they seal the can or bottle so
that none of the carbon dioxide escapes. If we
keep the soda cold, we can keep most of the carbon
dioxide in for a tasty, fizzy drink.
But what does that have to do with the volume of
gas in a balloon? Well, whether a gas is trapped
in a balloon or dissolved in a soda, it won’t
change too much how the gas behaves. So, when soda
gets warm, the carbon dioxide gets warm, and it
can travel faster and escape your drink. If you
had gas in a balloon and you heat it up, the gas
molecules would start traveling faster in the same
way. This time though the fast gas molecules
strike the balloon walls harder than before, and
the balloon will have to get bigger and bigger.
This observation resulted in what is now
called Charles’s Law, which says that the ratio
of temperature and volume of a gas should remain
the same. If you add heat, you should increase the
There is a law in science called Charles’s Law
which states that as temperature increases in a
gas, its volume will increase. When the
temperature of a gas increases, each molecule
generally gets more energy and moves faster. One
way to think about this is that the faster moving
molecules need more room to move about, so if
nothing is stopping the volume of the container
from expanding, the container will get larger.
Since a balloon is not a fixed container, as heat
is added, it will expand.
How pressure and temperature interact in a closed
system can be understood with one simple equation,
PV=nRT, or the ideal gas law.
Pressure multiplied by volume is equal to the
amount of gas “n”, multipled by the gas constant
“R” and temperature. If you increase temperature,
pressure and volume will also increase.
Temperature is proportional to volume in a
gas, so the higher the temperature for a given
number of gas molecules in a balloon, the larger
the volume of the balloon.
The more heat a gas has, the more kinetic energy
its particles have.That kinetic energy
generally means how fast particles are moving. So,
since, the particles of the gas are moving quickly
and bumping into each other more when hot, a
heated balloon will expand. A cooled balloon
Air expands when it is hot, so heating the
air in a balloon will puff up the balloon.
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