Weathering rocks

Weather rocks to show how water weathers rocks into small particles of sand and mud.
Science content
Earth/Space: Landforms, Erosion (3)
Earth/Space: Rock cycle, Earth Materials, Natural resources (5)
  • screw cap jars, one for every two to four students, filled with water
  • pieces of pottery e.g. from a broken terra cotta plant pot, about 2cm square or equivalent
  • optional: pieces of chalk, granite or other rock, to compare to the pottery

Distribute a jar of water and a couple of pieces of pottery to each pair or small group of students.
Explain that they will mimic the way that flowing rivers and the rain interact with the rocks on mountains.

Ask students to add their pottery pieces to their jar and screw on the cap. The pottery pieces are rocks.
Ask students to vigorously shake the jar. They are mimicking water and wind bashing the rocks, and wearing them away - the process of weathering. With the pottery, the pieces are broken into smaller particles much much faster than most of the natural weathering of the harder rocks of mountains.

Students look inside their jar to see that they have made smaller particles from their rock, then draw what they see. The left side of the second page of either attached worksheet can be used.

Explain that as rocks are worm away, they make sand and mud particles. Sand particles are larger and mud particles are smaller. The particles are washed into streams, then rivers, then the ocean. In the ocean they are carried by the currents until they are deposited in a calm shallow bay. Over a long time, a sand and mud beach is made, and continues to be built upon.

Optional: compare chalk and granite gravel. Do they break apart more quickly or slowly than the pottery.


Try chemical weathering with a dilute acid over several days. Vinegar and chalk.
TeachEngineering activity: Rocky-to-Sandy Beach: A Weathering Model uses candies of different kinds and sugar cubes to show weathering.

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5