Idea for a child's book to explain this framework.

 Chapter 1: Welcome to the Temperature Station!

"Brrr! It’s chilly here at the Temperature Station. All around you, thermometers rise and fall, steam rises from hot cocoa, and snowflakes drift through the air. You’re waiting to board a train, and there are two choices:

First, there’s the k Express Line. This train goes straight to Energy Town, where everything is bright and glowing. It’s a fast ride, and you’ll be there in no time!

But wait—there’s also a local train called $K_{\text{Hz}}$. This train doesn’t go straight to Energy Town. Instead, it takes you to the Frequency Station, where everything is wiggling and waving. Do you want to take the express or the local?

You decide to hop on the local train. Choo-choo! Off you go!"

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Chapter 2: The Frequency Station

"Whoa! The Frequency Station is full of colors and sounds. Light waves shimmer like rainbows, and sound waves bounce around like music. You see another train waiting at the platform—it’s the h Express Line, which goes straight to Energy Town.

We could go back to the Temperature Station from here on the Hz_K local line.

But there’s also another local train called ${\text{Hz}}_{\text{kg}}$. This train goes to the Mass Station, where everything is heavy and solid. Do you want to take the express to Energy Town or hop on the local to Mass Station?

You decide to take the local train. Choo-choo! Off you go!"

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Chapter 3: The Mass Station

"Wow! The Mass Station is huge. There are rocks, planets, and even stars here. Everything feels heavy and solid. You see another train waiting at the platform—it’s the c² Express Line, which goes straight to Energy Town.

But there’s also a local train called ${\text{kg}}_J$. This train goes back to the Temperature Station, where you started. Another local train goes back to Frequency station. Do you want to take the express to Energy Town or hop on the local back to Temperature or Frequency Stations?

You decide to take the express this time. Choo-choo! Off you go to Energy Town!"

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Chapter 4: Energy Town

"Welcome to Energy Town! This is where all the express lines meet. The k Express Line from Temperature Station, the h Express Line from Frequency Station, and the c² Express Line from Mass Station all end up here. Energy Town is bright and glowing, full of light and power.

But here’s the secret: Energy Town isn’t the only important place. The Temperature Station, Frequency Station, and Mass Station are just as important! You can take the local trains to hop between them anytime you want, and each place is just as good!

So, where do you want to go next? Back to Temperature Station? Or maybe explore Frequency Station again? The choice is yours!"