IB ESS T1-8 (SL + HL) 2025/2026

Positive Feedback

feedback system that tends to amplify the output of the system. E.g. Global Warming

Negative Feedback

system responds in an opposite direction to the original change. E.g. body temp heating up on hot day, sweat, body loses heat.

Isolated System

doesn’t exchange matter or energy with surrounding environment.

Closed System

A system which exchanges energy but not matter with its environment

Open System

exchange matter and energy with its surroundings. Most systems are open.

1st law of thermodynamics

energy cannot be created nor destroyed, it can only change state.

2nd law of thermodynamics

the entropy of a system will increase over time.

number pyramid

shows numbers of different organisms at each trophic level. It shows the population size of each species in a food chain.