Relative Age: Painted, Cut, Screwed, Glued, and Taped Wooden Blocks

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Kate Pound, North Hennepin Community College


Multiple sets of relative Age blocks
Instructions and materials list for making blocks


A series of sets of wooden blocks all contain varying records of the order in which the blocks have been painted, cut, screwed, glued, and taped. These blocks are used in introductory geology courses at the college level as well as with elementary, middle- and high-school teachers in workshops. Many teachers have made their own blocks. The blocks are used at the start of a 'unit' on relative age. Students use critical reasoning to determine the relative order of the steps involved in fabrication of 'their' block – and realize that the blocks record a variety of orders; students have to work together to compare and discuss how their blocks differ, and the evidence they have used. The concepts of 'relative age' as inferred from geologic cross-sections can then be applied as students equate the block events with geologic events (e.g. cutting = faulting). This activity brings all students a 'real-life' experience of relative age in multiple dimensions, which improves their confidence and skills when they advance to working with geological cross sections.


1. In college-level introducory geology classes
2. With K-12 teachers in Earth Science Teacher Workshops

Why It Works

1. Provides tactile materials that demonstrate relative age in a fun challenge
2. Allows students to reason and explain order of events without getting hung up on geological terminology prior to working on relative age in cross-sections
3. The use of the screw (as opposed to a nail) was intentional. The students won't forget it - although it can be easily replaced with a nail for any educators that have discomfort using the word.

Presentation Media

Educator Handout and Instructions for Relative Age Blocks WORD file (Microsoft Word 2007 (.docx) 5.7MB Dec16 22)
Educator Handout and Instructions for Relative Age Blocks PDF file (Acrobat (PDF) 1014kB Jul7 22)