Rock layers and relative dating
Most sedimentary rocks are laid down in flat, horizontal layers. These can later tilt and fold due to tectonic activity, and river cuttings can cause gaps among the layers. Geologists are able to ‘read’ the rock layers using relative and absolute dating techniques. Relative dating arranges geological events – and the rocks they leave behind – in a sequence. The method of reading the order is called stratigraphy (layers of rock are called strata).
In this activity, students observe rock layers located near Whanganui, watch an animation about how they were formed and use relative dating to work out the order in which rocks were created. The activity offers literacy opportunities as well as practice using the science capability ‘Interpret representations’.
Relative rock layers
Use this interactive to work out the relative ages of some rock layers from youngest to oldest. Drag and drop the text labels onto the diagram. Selecting or hovering over a box will highlight each area in the diagram. If you hover your mouse over the text labels there is more information about the rock layers.
If you want to redo an answer, click on the box and the answer will go back to the top so you can move it to another box. If you want to check your answers, use the Reset incorrect button. This will reset incorrect answers only. When you are happy with your selection, use the Check answers button to check them. Use Reset all to practise again from the start.
If you haven't already, we recommend you watch this animation before you use the interactive.
By the end of this activity, students should be able to:
observe, discuss and compare rock layers in a photo and a diagram
use reading skills to correctly label an interactive rock layer diagram
use oral and written language skills to narrate a video animation about rock layer formations.
Download the Word file (see link below) for:
background information for teachers
teacher instructions
student instructions.
Nature of science
Scientists use diagrams and models to communicate information. Students need support and practice to become familiar with and know how to use these science communication tools.
Related content
This activity is part of our collection on dating the past. The introductory article has links to related articles, activities and media.
