• Definition: A change where no energy is transferred between the surroundings and the system.
• How? By having an insulating boundary between them. So, even if they're at different temperatures, energy doesn't transfer!
• Real-world example: Imagine wearing a perfect thermos flask as a suit. It's freezing outside but you're boiling hot inside - yet, the cold can't touch you because of your 'thermos suit'.

• In an adiabatic process: Q = 0 (because no energy is moving in or out).
• The formulas to keep in mind: (Note: 'ΔU' is the change in internal energy; 'W' is work done.)
• 0 = -ΔU + W (work done on the system increases its energy)
• 0 = ΔU - W (work done by the system decreases its energy)

• For an ideal monatomic gas (like helium atoms flying solo): PV^(5/3) = constant. Don't worry about why for now - just know it's like a secret handshake for gases!
• Some handy equations:
• At constant temperature: P1V1\(\frac 53\) =  P2V2\(\frac 53\)
• When pressure is constant: T1V1\(\frac 53\) = T2V2\(\frac 53\)

Picture a roller-coaster track showing the pressure and volume of gas. An adiabatic change is like a steeper, crazier part of the track, while the isothermal changes are gentler slopes.