The science of the perfect baked potato (Spud Physics)
To use practical workshops to explain to the public the physics underlying conventional and microwave baking of potatoes and the consequent texture and flavour.
1. To raise awareness of the different types of heat transfer occurring when potatoes are baked in a microwave oven compared to a conventional oven and the effects on texture and flavour.
2. To work with Newcastle Centre for Life to deliver the workshops to community groups in the region, Women’s Institutes, families (visitors come from all over the world) and GSCE/‘A’ level students.
3. To involve undergraduate students in development of the practical exercises to be used in the workshops and Science Communicators in workshop delivery.
Summary of activity:
Participants baked different varieties of potato using a microwave oven and a conventional oven. At intervals during baking they measured: temperature of the potato core and surface using a thermometer, water loss by weighing, and texture. Cooked potato flavour was assessed by tasting microwave baked flesh versus conventionally baked flesh, and surface flesh versus core flesh. Flavour development in baked potatoes is inversely related to reducing sugar content and reducing sugars were measured using a modified Fehling’s method. Participants tested for links between data sets, especially between tuber temperature and moisture loss versus texture and intensity of specific potato flavour notes (baked potato skin, boiled potato. potato chips).
The workshop was delivered to around 200 people between September and December 2011. It is now part of the Centre for Life LifeLab programme (which delivers workshops to more than 20,000 people each year).
A Northumbria University undergraduate student and a Postdoctoral Research Fellow developed methods to (1)assess potato texture based on measuring the force required to pass a given thickness of tuber through the holes of a potato ricer disc and (2)measure reducing sugars in potatoes.
We used questionnaires to evaluate the project. The following eight questions were asked. The responses were used to help us improve subsequent sessions of the workshop.
1. What single words would you use to describe today’s workshop?
2. How enjoyable was the workshop? (scale 1 (pants) to 5 (great))
3. How easy was it to understand? (scale 1 (duh) to 5 (easy peasy))
4. What could we do better?
5. How often do you eat baked potatoes?
6. How are they cooked?
7. Thinking about ways of cooking and type of potato, do you think your consumption of baked potatoes will change in the future?
8. Is there anything else you would like to tell us about the workshop?
What went well:
1. Engagement of people of all ages (school children, teenagers, families, young adults, retirees, disabled (deaf) adults) in a physical science workshop.
2. Seeing the excitement of the participants at ‘doing’ science for themselves, especially involving something with which they were all familiar – the baked potato.
3. Development of the workshop to focus on the suitability of different varieties of potato for baking through differences in texture and flavour. This is something people do not think about too much but participants realised as a result of attending the workshop that their enjoyment of baked potatoes depends very much on the interaction between variety and mechanism of heat transfer, i.e., the baking procedure.
What was learned:
1. Being prepared to adapt the workshop protocol to different groups of participants so that everyone can engage at an appropriate level.
2. Letting participants start the workshop by microwave baking a potato so they could obtain data about weight loss and we could explain about latent heat of vaporization and thus engage them with physical science concepts from the start.
3. To let the participants obtain measurements for texture and sugar using the microwave baked potatoes first. The conventionally baked potatoes took 75 min to cook and so these were examined towards the end of the workshop.
Top tips and advice for others
1. Be prepared to adapt the workshop to the audience.
2. Practise the workshop to get timings right and with a ‘guinea pig’ cohort to get good feedback.
3. Don’t try to get across too much information and make it too complicated. Focus on audience engagement and experience.
4. Involve students in workshop development activities. They have good ideas and bring a fresh perspective.