Imagine a summer day where the temperature stays the same throughout. Now think of a gas that undergoes changes but its temperature remains unchanged. That's an isothermal change for ya!

• Internal energy remains constant: It's like having the same amount of money in your wallet all day, no matter how much you spend or earn!
• Temperature doesn't change :Like your ice-cream not melting on a steady cold day.

Remember, Q = ΔU + W. But here, ΔU = 0 (because internal energy is constant). So, Q = W.
Think of it like this: If you get $10 and you don't save any of it, you spend the whole $10. In this case, the "spending" (work) equals the "getting" (thermal energy)

Gas in a balloon:

• +W (positive work): Imagine blowing up a balloon. As it expands, the gas inside is doing work against the atmosphere (like the balloon pushing outward).
• -W (negative work): Now, press the balloon! Energy transfers away from the gas as you compress it. The atmosphere (or you) is now doing work on the gas.