Great question, Wanda! Water is a bit of a mystery, isn’t it? But the answers lie deep within the molecules themselves. How about we dive in and take a closer look?
Ms. Frizzle, why does water take so long to boil compared to other liquids? And why does it seem to stick to everything?
In Mrs Frizzle's classroom the students have been buzzing with activity as they work on a science experiment. On the board, Ms. Frizzle has written "Why is Water So Special?" The students are puzzled as they look at a beaker of boiling water.
Slayt: 2
Intermolecular Forces
.
It's your turn to be the ant monitor, Arnold.
Is it always like this in Ms. Frizzle's classroom?
You'll get used to it.
The ant monitor?
She explained the lesson, but no one understood it."I guess we'll have to go on a field trip," said Ms. Frizzle.
Slayt: 3
Class, get ready! We’re going on a journey to discover the secret life of molecules!
The students run out to the Magic School Bus that was parked outside. They pile in, and the bus roars to life.
Slayt: 4
I'm getting dizzy.
Are we almost there yet?
Fasten those seatbelts, children.
We never did this in my old school.
You never know what will happen on a trip with Ms. Frizzle. On this trip, the bus started to spin like a top. When the spinning stopped, everyone was somehow smaller and inside a water droplet."Alright, class," Ms. Frizzle said, "pay close attention as I explain the fascinating world of intermolecular forces"
Slayt: 5
So that’s why water sticks together so well! It’s those hydrogen bonds holding the molecules close!
Polar? Like the North and South Poles?
What are those lines connecting the water molecules?
Those, Arnold, are hydrogen bonds—a special type of dipole-dipole interaction. They happen because water molecules are polar.
Great connection, Phoebe! When we say a molecule is polar, we mean that it has a positive end and a negative end, just like Earth has a North and South Pole. In water, the oxygen atom pulls the electrons closer to itself, making that end of the molecule slightly negative, while the hydrogen ends are slightly positive.
Mrs Frizzle explained to the class that this was also why water has such unique properties, like being able to dissolve so many substances and having a higher boiling point than other liquids. It all comes down to polarity and those cool hydrogen bonds.
Slayt: 6
I'm getting dizzy.
Are we almost there yet?
We never did this in my old school.
Fasten those seatbelts, children.
The bus is now inside a water droplet, surrounded by moving water molecules. The students watch in awe as the molecules vibrate and occasionally bond together.