A1.1.4—Adhesion of water

Adhesion attracts water to other polar or charged surfaces, supporting capillary movement through narrow spaces such as soil pores and plant tissues.

How it is assessed

This objective is assessed through multiple choice, commonly using Identify.

Command terms

Identify

What earns marks

A complete answer identifies the different surface involved and links the attraction to capillary movement.

Watch for

Using adhesion and cohesion as interchangeable terms.

Representative question

[Maximum number: 1]

Which of the following is a consequence of the adhesive properties of water?

Stable temperatures of aquatic environments

Water movement by capillary action in soil

Transport of dissolved nutrients in blood plasma

Cooling effect of sweating

Water is life's medium because substances can dissolve, move and react in it.
Unequal electron sharing and bent geometry make water polar; hydrogen bonds form between molecules.
Many hydrogen bonds produce cohesion, maintaining xylem columns and creating surface tension.
Adhesion is water-to-surface attraction and contributes to movement through narrow soil spaces and cellulose walls.
Polarity lets water hydrate ions and interact with polar solutes; dissolved particles can be transported and react, while non-polar substances are hydrophobic.
Compared with air, water provides more buoyancy and drag, transfers heat faster and changes temperature more slowly. Aquatic adaptations respond to these consequences.

Concept essentials