Hey Ray: The thirsty bird
PITTSBURGH (KDKA) - If you follow me on social media, you know I like to feed the birds in my yard.
While I am a major "bird nerd", we're not talking about feeding the birds. Today, we are going to figure out a science experiment where a bird toy keeps taking a drink.
You may have seen this bird toy before. It rocks back and forth and then slows down. From there, the bird seems to take a drink and speeds back up. While this looks like a silly toy, there is a lot of complex science occurring to make this action happen.
More specifically: thermodynamics, chemistry, and physics!
You will notice that this bird is made of a glass bulb connected to a tube, balanced on a fulcrum, or point that this glass apparatus balances and pivots on.
There is also an absorbent material on the head of this bird that soaks up water when it drinks.
The secret is sort of in that red liquid. That is methylene chloride, a chemical that evaporates and condenses easily. Since that transfer between liquid and gas occurs so easily, the rest of this silly-looking, yet complex toy is able to work.
This whole process starts off when you get the bird's head wet.
The fabric absorbs the water, and as the bird rocks, that water evaporates. From there, the gas vapor inside the glass body condenses back into liquid form. This drops the pressure on the bird's head, forcing liquid up the inner glass tube because of that low pressure, causing the bird to become top-heavy and tip forward at the pivot point to take a drink, starting the process again.
This will repeat as long as there is water to evaporate.
There is something you can do to make it go faster, too. All you need to do is increase evaporation!
Alcohol evaporates faster than water, we will swap our water with rubbing alcohol. That evaporates quickly, speeding up the cooling, speeding up the drop in pressure, speeding up the red internal liquid, and speeding up the next drink.
A lot of science goes into making that silly-looking toy work!