Thermal Expansion of Water: Demonstration and Explanation

Lots of things expand when they get
warmer, for example air will expand. Like the air
and hot air balloons or even bridges will expand. That's why
they have to have a little metal teeth so that the bridges don't crack when
they expand. And of course water expands when it gets warmer. This is important because there's a lot of water on the planet Earth. And as the earth
gets warmer that water's going to expand and that expansion is gonna lead to sea
level rise. And that has a lot a big implications.

So to
experimentally show that water expands when it's heated we have a 100 watt light bulb and that is
in a reflective casing and we have a 750 milliliter
clear plastic bottle we have some food
coloring in there so it's visible and then we have a straw, and the straw
poked down through the bottle cap and it's sealed with a
little bit of caulk. so that no water can leak out. It's also
important to note that there's no air in the bottle or in the straw, below
the waterline, and that's important because
if we have air we're not really testing the thermal
expansion of water, we're looking at water and air we're not going to be able separate which
is which. So we're gonna start of it time equals 0 and we look at the
level of water in the straw. So at time equals 0 we have 13.5 millimeters of water in the straw. At
fifteen minutes it jumps up to 31 millimeters almost
double at 30 minutes we go to 43 millimeters and as that heat continues to make the
water warmer we jump up half-hour to 60 minutes at 71
millimeters another half hour, we're at ninety minutes
136 millimeters and finally we get to the 121 minute
mark that two hours and the waters almost at the top in the
straw 135 millimeters so that point we have to stop the
experiment because the water's gonna overflown we can't continue to measure at that point.

If we turn the light off
and we wait a while as the water cools it'll contract and
return to the original position. Now you might wonder why is all this
important we've shown that water expands as it's heated but why does it matter?
One reason that it matters is that the average global temperatures
are rising and they're only rising a little bit but
that little bit has big consequences Because we have quite a bit of water in the
ocean and even if that water only explains a little bit there's so
much of it that it contributes to sea level rise in fact thermal expansion along with ice
melting from the poles is one of the main things
that drives sea level rise so there you have it that's the thermal
expansion of water and one the consequences of
thermal expansion of water this is Dr.B, and thanks for
watching.

As found on YouTube

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