Description

Below, we present the main idea and equipment instructions of a hands-on activity called Playdough Core Sampling, that is used at CERN Science Gateway in the framework of 30-45-minutes-long workshops for student groups and families. 
In this activity, participants investigate boxes representing different geographic areas around CERN. They use transparent plastic straws to extract core samples of playdough and they record their findings by drawing them. Through observation and analysis of the colorful layers they extracted, participants then develop hypotheses about the different types of soil and materials hidden beneath the surface, just like geologists do in the field.
By learning about the composition of the ground, engineers can make important decisions, such as determining suitable locations for building tunnels, like those at CERN. You can learn more about CERN's possible future circular collider and current plans for geological assessments here. 

Material list

Here, we present the setup used at CERN Science Gateway. 

• Opaque plastic boxes
• Packs of playdough of different colours (count 3 to 4 packs per box)
• Transparent straws or cut-out pipettes (1 per student)
• Paper sheets and pens of the same colours as the playdough

Instructions

• Prepare all the material needed.
• In each box, construct 1-2 cm deep layers of playdough to simulate the composition of the ground. For example, in one box you can build a layer of blue followed by a layer of green, while in another one layers of green, red and black. Some layers can be made of two colours, e.g. a blue area representing groundwater in the centre of an otherwise black layer.
• You can label each box, e.g. “lake”, “mountains”, “valley”.
• Participants extract core samples and they observe them.
• Participants record their core samples by drawing them on their worksheet.
• Encourage participants to represent their sample as precisely as possible, by respecting the width of different layers.

Ideas for educators

• Start with a group discussion about what students think lies beneath our feet, and about the fact that it is impossible to know for sure. To get a better idea, we need to extract samples and make some guesses.
• Have participants work in groups of 4 to 6, assigning each group to a specific box. 
• Implement a rotation, allowing students to explore different boxes and compare findings. Allocate 8 to 10 minutes per phase.
• Insist on the importance of reporting the result on their worksheet to keep track of their discoveries. 
• Conclude by proposing to students to imagine and to build a machine that could be installed underground.