Weathering: physical, chemical, and biological

Water enables reactions and removes soluble materials. In exams, lack of water means slower chemical weathering.

In permeable rock, water and dissolved chemicals reach deeper parts. In exams, understand permeability as water entry.

Thermal expansion requires repeated temperature change. In exams, stable temperature indicates weak thermal weathering.

Weathering turns parent rock into broken material, forming the base for soil. In exams, link soil initiation with weathering of parent rock.

Microbes can produce acidic substances that weaken minerals. In exams, link bacteria and fungi with biological weathering.

On steep slopes, broken material easily moves downslope, so a thick layer may not form. In exams, connect slope with removal of material.

Heat, moisture, and acidic substances speed mineral reactions. In exams, the presence of all three indicates intense chemical weathering.

Pressure from salt crystals can loosen surface grains and create small pits. In exams, honeycomb surfaces often indicate salt weathering.

Physical weathering breaks rock while mineral composition generally remains the same. In exams, size change points to physical weathering.

In oxidation, oxygen combines with minerals to form oxides. In exams, combination with oxygen directly indicates oxidation.

Chemical reactions are accelerated by moisture and heat. In exams, treat climate as a major control of weathering rate.

Joints allow weathering agents to penetrate deeper and speed alteration. In exams, joint planes are zones of weakness.

Chemical weathering can alter mineral composition and produce new substances. In exams, formation of new minerals indicates chemical change.

Calcite dissolves easily in acidic water, so limestone is affected by carbonation. In exams, link calcite and limestone with carbonation.

Cracks allow roots to enter, and growing roots exert pressure. In exams, jointed rock plus vegetation indicates biological weathering.

Hydration mainly involves addition of water, while hydrolysis chemically alters minerals. In exams, both involve water but their effects differ.

Weathering weakens rock, making later erosion easier. In exams, treat weathering as preparation for landform development.

A thick cover forms when accumulation of weathered material exceeds removal. In exams, connect accumulation and slow removal with thick regolith.

Water works in both physical and chemical weathering. In exams, link water with frost, solution, and reactions.

Acids from lichens and mosses can chemically react with minerals. In exams, acid release indicates chemical biological weathering.

Quartz remains stable under many common weathering conditions, so it is chemically resistant. In exams, treat quartz as a durable mineral.

Weathering is the breakdown or alteration of rock in place. In exams, absence of transport is the main clue for weathering.

In high latitude mountains, thawing and freezing can enhance frost weathering. In exams, connect mountains with freeze thaw action.

In hydration, minerals may absorb water and expand, creating internal pressure. In exams, volume increase points to hydration.

Weathering is controlled by several natural factors, especially climate and rock properties. In exams, remember combined controls rather than a single cause.