1.2.5—Open vs. closed systems
- Syllabus
- First assessment 2026
- Objective
- 1.2.5
- Level
- HL
Check What Crosses the Boundary
An open system exchanges matter and energy; a closed system exchanges energy but not matter across its boundary.
Draw the boundary first, then inspect each crossing. A local ecosystem is open; global geochemical cycles are treated as approximately closed; a sealed terrarium may approximate closed for matter.
Light enters a terrarium and heat leaves, while its soil, water and gases stay inside: an approximate closed system.
No; water crosses the boundary, so the plot exchanges matter.
Closed does not mean nothing crosses; energy may still enter or leave.