Water (H₂O)
A molecule required for photosynthesis, supplying hydrogen and electrons.
At a glance
Key signals
63% cross fields · reaches 7 more
- Chemistry
- Biology
- Oceanography
- Explanation
- Examples
- Misconception
- Sourced relations 7
- Attribution
Dependencies
What this concept builds on and what it makes possible — derived from the atlas’s dependency, causal and structural relations, not from every related edge.
Enables · leads to
Germinationdepends onWater (H₂O)Established
germination depends on Water (H₂O).
Mechanism: Germination depends on water: soaking up moisture reactivates a seed's metabolism and swells it until the embryo bursts out.
- Biology 2e (OpenStax) (2018) verified
Humiditydepends onWater (H₂O)Established
humidity depends on Water (H₂O).
Mechanism: Humidity depends on water: it is simply how much of the water evaporated from oceans, lakes and plants the air is currently holding as vapour.
- Wikipedia (English & German editions) verifiedmoderate evidence
PhotosynthesisrequiresWater (H₂O)Established
Photosynthesis requires water.
Mechanism: Water is split to provide electrons and hydrogen for the reactions; the oxygen atoms are released as O₂.
- Campbell Biology — demonstrates this case · verified · moderate evidence · Photolysis of water supplies the electrons for the light reactions. (10 — Photosynthesis)
Transpirationdepends onWater (H₂O)Established
transpiration depends on Water (H₂O).
Mechanism: Transpiration is water evaporating from leaves, pulling a continuous column of water up from the roots.
- Biology 2e (OpenStax) (2018) verified
Water cycledepends onWater (H₂O)Established
water cycle depends on Water (H₂O).
Mechanism: The water cycle depends on water as the substance that moves through it — the same molecules cycling endlessly between sea, sky and land.
- Wikidata verifiedmoderate evidence
System context
Water (H₂O)is part ofRiverEstablished
Water (H₂O) is part of river.
Mechanism: Water is what a river is made of and moves: precipitation and groundwater feed a channel that carries the water downhill to the sea.
- Wikidata verifiedmoderate evidence
Water cycleis part ofWater (H₂O)Established
water cycle is part of Water (H₂O).
Mechanism: The water cycle is the journey water takes — evaporating, condensing, falling and flowing — that continually redistributes it across the planet.
- Wikidata verifiedmoderate evidence
Structural role & consequence
Interpreted from the current atlas graph — what the connections mean, not just how many there are.
Removing this node severs the only sampled structural route between Humidity and River — a non-redundant bridge here.
structural · Structural removal simulation — not a historical or causal counterfactual.
50% of its relationships cross field boundaries, reaching 7 other disciplines — unusual in a discipline where most concepts stay within their field.
structural · Structural graph analysis — not a claim of importance, causation or history.
Currently dark in the atlas: no key date stored · 8 of 9 of its relations lack claim-level evidence.
atlas representation · Describes the current Thinking OS representation, not the state of the world.
Structural neighbourhood: 8 → 39 → 111 concepts reachable within 3 hops.
structural · Structural reach — being reachable is not the same as being understood.
cross-field
4 within-field, 4 cross-field
Strengths & constraints
Strengths
- Cross-disciplinary connector — 50% of its relationships cross field boundaries. structural
Constraints
- Evidence coverage currently thin in the atlas — few of its relationships carry claim-level evidence. atlas representation
- Non-redundant bridge — removing it severs a sampled route between neighbouring clusters. structural
- No dated history stored — the atlas records no key date for this concept. atlas representation
Conditions
- Read structurally — most of its relationships carry no external evidence yet, so claims here are graph-derived. structural
Dependency radial
What this concept builds on (left) and what it makes possible (right) — derived from dependency and causal relations.
What builds on this
6 concepts build on this directly, 13 in total, across 12 disciplines.
Structural downstream reach along dependency edges — not a claim of historical necessity.
Seen through each discipline
How this concept sits in each of its fields — derived from its real connections in the graph, not asserted.
Through this lens it connects to Photosynthesis, Xylem, Transpiration and Germination.
Where you'll meet it
Journeys that walk you through this idea. You may recognise it from more than one.
Related ideas to explore
Concepts that look related but are not yet connected here — candidates for a connection to reason about, not established links.
This idea also appears in…
The same structure shows up in other disciplines. These are real recurrences drawn from the graph — a starting point for asking “what carries over, and what changes?”
Concepts
crosses a discipline boundary
crosses a discipline boundary
crosses a discipline boundary
crosses a discipline boundary
- Connects 8 other ideas across 3 disciplines.
- A cross-disciplinary bridge — its connections reach into 7 other fields.
- Most of its connections are of the “Dependency” kind.
- It features in 1 learning journey.
Derived from the graph’s real structure — observations, not a score.
Sources
- Brackish water and low specific water flow during smolt production affect growth and susceptibility to <i>Moritella viscosa</i> after seawater transfer (2025) verified
- CHAPTER 24: Emerging Technologies for Irrigation Water Treatment (2017) verified
- Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H 2 O 2 and HNO 2 (2014) verified
- Water (2012) verified
- Water colour index of the Guinean sector of the Atlantic Ocean (1990) verified
- 3. High-resolution Optical Imaging for Deep-water Archaeology (2008) verified