Summer school: Insane Grains

Last year this course was known as: Hands On Physics.

In this course you will take an interactive, hands-on approach to learning about the curious and often insane world of granular materials, often referred to as the fifth state of matter.

What makes granular/particulate materials so popular and so important?Anthony Thornton (course leader)

First of all, they exist almost everywhere in the universe, they range from nanoscale to planet-sized, from sands to our breakfast cereals to asteroid fields! It is estimated that 10%, yes 10% (!) of the energy production of the world is expended manipulating granular materials - from the cement in building to the powders which make up modern day medicines. Whether you want to mine for gold, drill for oil or land a spaceship on Mars, an understanding of granular materials is vital.

Granular materials

These materials are also key to our understanding of various catastrophic natural phenomena, including snow avalanches, debris flows, volcanic eruptions and earthquakes. By studying granular media, it is hoped that one day we may be able to better predict, or even prevent, these devastating events.

Finally, granular media demonstrate a plethora of fascinating - and often unique - behaviours. For example, adding water to a sand pile can make it mouldable; we all exploited this phenomenon to build sand castles when we were younger! Granular materials exhibit a huge range of behaviours and can behave like a solids, liquids or even gases. All three states are easy to see in a simple hour glass; where the static materials transforms into a liquid avalanche before falling thought the hole as a granular gas.

Course topics

Click the topics to get detailed information!

Escaping Quicksand

Anyone who has ever watched a classic western movie knows about the dangers of quicksand. You know that glooey stuff that grabs a hold of its victim and swallows them alive? So, what is quicksand and how does it really work?

To unravel the mystery, we will make use of simple cornstarch in order to replicate the behaviour of real quicksand. Most fluids can be called Newtonian: the faster they move, the easier they flow. However, quicksand (a mixture of grains and fluid) behaves differently. It is closer to a solid when moving faster but liquid at a slower speed. You will make your own quicksand and learn to understand its properties. We will even fill a paddling pool with quicksand allowing us to learn how to really escape quicksand.

Shakes and Quakes

This follows on from the Escaping Quicksand workshop and looks at the physics of earthquakes. Here we look at materials that have the exact opposite properties of the cornstarch considered before. The work focuses on soil liquefaction whereby a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden changes in stress condition, causing it to behave like a liquid. This leads to interesting effects like sewers raising to the surface and buildings sinking into the ground during earthquakes.

This very hands-on workshop will experiment with liquefaction and explain how and why it happens.

Granular dampers

While a loose packing of grains provides little resistance against shear or normal forces (one can easily deform a bag of sand), its rigidity increases immensely when the material is compacted (jammed). This can be achieved by packing granular material into an airtight balloon and applying a vacuum. Thus, the strength and shape of such a material can be controlled by varying the degree of compaction.

We use these properties to create a "granular gripper". This instrument uses the variable shape of the loose material to grip an object (such as a glass), then applies a vacuum to increase its rigidity in order to hold the object and transport it. We also construct a floating bridge, which can be folded for transport, then flattened out and hardened when in use.

Games of sand

We finish with the games of sand or granular olympics. Here you use the knowledge and skills you have learn to solve problems and challenges which are both fun and relevant to modern society.

Course details

  • Methods: A mix of group and individual projects, all of them hands-on.
  • Course level: Beginner’s
  • Target group: Bachelor’s students with an interest in physics. 
  • Required knowledge: No previous knowledge required.
  • Course leaders: tbc
  • Credits: 2 ECTS for successfully completing the summer school

For further information or questions please send an email to: