Straw Scaffold
Build a scaffold out of drinking-straws to support a cup of water
Age
11 to 14
Challenge level
Problem
Image
The scaffold needs to reach the roof of the cathedral, and be able support the weight of the company's cement mixer.
The company has asked you to find out the most efficient way of making the scaffolding.
Your brief:
1. Produce a model of the scaffolding using only the drinking straws and sellotape provided.
2. The straw scaffold must be able to hold a beaker of water (which models the cement mixer) at a height of at least 50cm from the floor.
3. The scaffold must stand without support.
The best design will be the one that can bear the greatest volume of water, using the least materials.
You should record the number of straws you used and the greatest volume of water your scaffold would bear.
You should also work out a method to compare your structure with other groups'.
Equipment required (per group)
100 drinking straws
1 metre rule (for assessment)
Sellotape
A small plastic beaker (avoid glass in case of breakage!)
Water (and plenty of newspaper or similar to place underneath the scaffold to mop up any spills of water)
Teachers' Resources
Why do this problem?
Building a model scaffold will require students to work in groups. To be successful, a group will need:
- team work
- good communication
- leadership
- self-discipline
These are all skills required in Design Technology.
This activity is based on a resource from Richard Hall and Michael Acheson, two of the teachers involved in the very successful STEM teacher inspiration days, 2011-12. You may also be interested in the resources used in the Dragster workshop on TI day 2.
The practical activity will help students to develop an understanding of forces which will help them in both Maths and Science later on. Groups should also assess which structure can bear the greatest volume of water for the least number of straws. To do this, they will need to discuss how they are going to calculate the volume : number of straws ratio to ensure that there is a common criterion in the class.
Possible approach
This would be an ideal lesson for a visit from one of the Design Technology department, who could lead an initial discussion about how to design and test the scaffold.For an hour lesson, a suitable division of time would be 40 minutes to test, plan and build the scaffold, and 20 minutes for assessment and discussion.
One way to avoid too much mess is to give groups a beaker and small cubes to test their structure, and only make water available at the final testing.
Key questions
- How can you compare scaffolds so you can work out which fulfils the brief best?
- What features characterised successful scaffolds?
- What features characterised successful groups?
Possible extension
- Finding the maximum amount of water that can be supported by a given scaffold.
- Deciding on whether there are redundant straws in the structures.