Shake Table

This resource is a guide for running a shake table workshop with your students, using simple materials to build small scale shake platforms and towers that represent how engineers and scientists test building structures under earthquake-like conditions. Engineers usually test structures until they reach seismic failure (i.e. collapse at different degrees of movement) and they analyse data to further test and strengthen buildings against collapse in earthquake-prone areas.

The workshop’s two part hands-on design thinking challenge includes the construction of a desktop-sized shake platform then building a tower on the shake platform that survives and collapses at different degrees of shaking (seismic failure). The activity encourages participants to observe, try and refine different prototype designs, modeling the innovation process and developing creative problem solving skills. The activity also incorporates a smart phone app which roughly displays the amount of shaking according to the Mercalli Scale.

Lesson Outline

90 Minutes

The below lesson outline provides an overview of workshop elements

Please ensure you follow your school WHS procedures while conducting this lesson

Introduction

10 minutes

Introduce the activity ive some context to what a shake table is and , including how scientists use large scale, controllable platforms to test seismic failure of building structures. The largest seismic testing platforms are typically found in earthquake prone areas like Japan, China and California. Check out some videos of real life examples at this YouTube shake table playlist.

Initial Challenge: Create a shake table

20 minutes

Working in groups of two or three, create a ‘shake platform’ that fits on a desk or table top. Try setting a limit of using only four different types of materials (in any volume). Attachment material such as masking tape or hot glue isn’t included in the material limit.

The shake platform’s movements must be controlled by hand. Test and refine the shake platform design. Initially you may just aim to make the table shake back-and-forth and side-to-side, but if this is achieved easily, try and make the table shake up and down too.

A piece of card sits horizontally on top of five coloured balloons.

Introduce the phone app

5 minutes

Place a smart phone or tablet containing the Smart Tools vibration app onto your shake platform. Shake your platform by hand and observe how the vibration app detects movement.

The effect of an earthquake on the Earth's surface is called the intensity. The intensity scale consists of a series of certain key responses such as people awakening, movement of furniture, damage to chimneys, etc.

While the magnitude of earthquakes are often reported against the Richter Scale, scientists also used the Modified Mercalli Intensity Scale. The correlation between earthquake magnitude and intensity depends upon:

  • the depth of the earthquake
  • surrounding terrain
  • population density
  • building density and observable damage.

Source: The Modified Mercalli Intensity Scale, US Government

Main Challenge: Build a tower

30 minutes

Build a tower for your shake platform using up to four materials of your choice and attachment material such as masking tape or hot glue. Other guidelines may be more suitable for your students, but during this workshop, we set the following parameters.

Your tower must:

  • be fixed at its base to the shake table
  • be at least 30 cm high
  • hold a 100 g mass around mid-way
  • survive shaking on your ‘shake table’ BUT topple over at Mercalli VIII.

Two adults are sitting on the left and right, respectively, looking to the centre of the table where a third person is holding a card platform. The platform is resting on top of some coloured balloons. On top of the platofrm sits a mobile phone and a cylindrical card tower is attached to the platform with masking tape.

Optional: To increase the challenge for students, try one of the following options mid-way through the tower build session (depending on how you think your students will respond).

  • Ask whole groups to move clockwise to the next table and keep working on that next group’s tower
  • Ask 1-2 people from each group to move to a different group and work on the new group’s tower with existing members who stay in place
  • Tell groups to return one of their remaining materials to the supply table, so groups are limited to whatever material is left on their desk

These techniques help participants to avoid over analysing their model and encourage participants to undertake more hands-on testing through trial and error. It also offers opportunities for older groups of students to see how other groups changed their model and whether there were unexpected changes at the end of the session.

An adult is moving a platform made of card back and forth over some pieces of wooden dowel. A mobile phone and cylindrical card tower are attached to the platform with masking tape. A second person is looking at the platform and smiling.

Wrap-up

20 minutes

Each group demonstrates/tests their shake table and tower for the group and reflects on:

  • How they went about designing and testing different models
  • What worked well, what didn’t work well?
  • How would you improve those designs given more time or resources?

Shake table deconstruction: remove tape and glue to allow you to reuse as much material as possible. If materials can't be reused, try and recycle them.

Tools And Materials

Any available materials can be used to build the shake platform and a tower, but the suggestions below offer a starting point.

A range of materials are spread across a table. Materials include wood offcuts, marbles, golf balls, stockings, popper juice bottles, rubber bands, excercise bands, ballons, plasticine and cardboard folders

Board like materials: Stiff boards such as old arch lever folders, small pieces of plywood, plastic Frisbees, etc.

Tower building materials: Drinking straws; wooden skewers; paddle pop sticks; toothpicks; dry spaghetti

Attachment and joining materials: Plasticine; BluTac; masking tape; elastic bands; stockings; yoga resistance bands, etc.

Rolling/movement materials: Marbles; squash balls; ping pong balls; wooden balls, etc.

Holding materials: Sandwich bags; sand; paper clips; balloons, etc.

Tools, including: scissors, safety knives, hot glue guns, saws/drills and safety glasses - dependent on materials and WHS

Optional: mobile phones with a protective cover and the Smart Tools Vibration Meter app installed (Android only)

Further Investigations

Disaster relief architecture is a large area of research and development. For example, Hexayurts are transported and delivered as flat packs, so hundreds can be delivered to refugee camps, etc. for emergency shelter and transitional housing. A Plywood Hexayurt costs around $100 and takes a few hours to erect, with few loose parts. Painted plywood Hexayurts are believed to last for up to three years and can withstand strong winds and rains as well as earthquake aftershocks. Students could build model Hexayurts to test on a shake platform.

Explore the resource area for teaching (RAFT) website and try and recreate their build designs for an unmotorised shake table and a motorised shake table.

Create a giant shake table by turning a desk/table upside down onto semi-inflated balloons. Hold the table’s legs to control movement and gently move the table back and forth. Use the giant shake table to build larger or interconnected buildings and test larger or interconnected towers.

Explore liquefaction of soils using cornflour slime. Place cornflour slime (2 parts cornflour: 1 part water) inside a large zip-lock bag. Expel all the air and seal the bag. Place it under the tower (on top of the platform) to represent liquefaction of soil during an earthquake.