ScienceFreePrintable

Types of Weathering Explained

A free science worksheet ready for your classroom. Open in Kuraplan to grab the print-ready PDF, customize it for your students, or generate a fresh version in seconds.

Download now

Name:Date:

Types of Weathering Explained

A class geology team is investigating how rock breaks down around Aotearoa New Zealand. Read the field notes, then use evidence to identify weathering processes. Weathering breaks down or changes rock in place; erosion transports the loosened material. Some examples involve more than one process.

Field notes

At a limestone outcrop, rainwater seeps into narrow cracks. As it absorbs carbon dioxide from the air and soil, it becomes a weak carbonic acid that slowly dissolves calcite in the limestone. Nearby, water enters joints in a cliff and freezes during cold spells. The expanding ice widens the joints; repeated freezing and thawing eventually loosens angular fragments. Plant roots grow into some cracks and push them wider. Dark iron-bearing minerals on an exposed rock surface have also reacted with oxygen and formed reddish-brown compounds.

Analyse the evidence

1.Which statement best distinguishes weathering from erosion in the field notes?

Weathering breaks down or changes rock in place; erosion moves material away.
Weathering moves rock downhill; erosion changes minerals in place.
Weathering happens only in cold places; erosion happens only in rivers.
They are two names for the same process.

2.Classify each process in the field notes as mainly mechanical, chemical, or biological weathering: (a) ice widening joints, (b) carbonic acid dissolving calcite, (c) roots pushing cracks wider, (d) iron reacting with oxygen.

3.The limestone dissolution described is a chemical reaction. Explain what changes in the rock, and why this differs from simply breaking it into smaller pieces.

4.Match each process to its best explanation: A. oxidation; B. frost wedging; C. root wedging. 1. Water freezes in a joint and expands. 2. Iron-bearing minerals react with oxygen. 3. Growing roots exert pressure in a crack.

A. Oxidation
B. Frost wedging
C. Root wedging

3. Growing roots exert pressure in a crack
1. Water freezes in a joint and expands
2. Iron-bearing minerals react with oxygen

Test a claim

A student says: “If rock breaks into pieces, it must be erosion.” Use the ideas from the field notes to evaluate this claim.

5.Is the student’s claim correct? Give a counterexample from the field notes and explain what would need to happen for erosion to occur.

6.Suppose the limestone outcrop were covered by a thick, impermeable layer that stopped rainwater reaching the cracks. Which process in the notes would be reduced most directly, and why?

7.A nearby rock face has orange-brown staining. Identify a likely weathering process and name the mineral element involved in the reaction.

8.Make a labelled sequence diagram showing frost wedging in three stages: water enters a crack, freezing widens it, and fragments loosen. Include arrows to show the change over time.

9.New Zealand has limestone landscapes as well as cold alpine environments. Predict which setting is more likely to show strong carbonic-acid dissolution and which is more likely to show frequent frost wedging. Give one reason for each prediction.