Once upon a time, there were three little molecules. 

They did almost everything together, and they were the very best of friends ever since they were tiny molecules.

The three little molecules loved to be with one another. They were each alike in many ways, so they responded similarly to changes in temperature.

One was named Tom, the other Jake, and the last one was called Minnie.

Hi Jake! Hi Minnie!

Hi Tom!

Although they had very different personalities, they generally shared some things in common whenever the weather changed...

In the summertime, they loved to play outside in the hot summer weather. Tom, Jake, and Minnie would run off in all different directions in the summertime.  

Their parents often sent them outside to keep them from bouncing off of the walls indoors when it was hot.  

But the summer days didn't last very long, and soon the cooler autumn days began. The temperature got a lot cooler outside and the three little molecules would come closer together to play.