I reminded her that it was only GCSE technology and not A-level, and that a local builder had already said her plans were better than many from professional architects.
Two years later, another GCSE student was equally upset about her experiments to find the force required to rewind an audio tape. She was designing a hand-powered tape winder to save batteries and needed to calculate gear ratios. Girls can become passionate about technology - yet too few see it as relevant.
The introduction of design and technology at the independent girls' school where I teach has been very successful. Last year a third of GCSE pupils opted for craft, design and technology; 63 per cent achieved grade A, 37 per cent grade B, and half are now taking the subject at A-level.
The social dimension of the course made it attractive to many girls. The course begins by investigating human need. We present the whole subject in terms of making the world a better place. This simple yardstick is always used to evaluate projects, an approach that does not conflict with technical rigour.
One of the course projects for 14-year-olds was launched by the Child Poverty Action Group with a presentation about poverty in single-parent families. The pupils investigated ways to support a local self-help group of one-parent families. They devised mechanical control systems for money boxes with cams and cranks and set up small enterprises to batch-produce food and gifts. Such learning should delight the Engineering Council, which has led the drive for an industry-centred curriculum.
Our chairman of governors, who is confined to a wheelchair, spoke to GCSE groups about her life, mentioning the difficulty she had in reaching bookshelves. So one student designed shelves that move up and down inside a larger case, like a dumb waiter - a most successful engineering project.
Researchers in the Seventies and Eighties, especially those in the 'Girls into Science and Technology' programme, demonstrated that girls willingly become involved in technology if the social dimension was central to the subject.
Girls want to face the challenges presented by modern society. The architects of the technology curriculum recognised this, and require pupils to investigate an area of human need. Students acquire skill in designing and making - whether the medium be food, construction materials, textiles, graphics - and learn to appraise the effects of technology against a growing understanding of people.
Properly taught, the existing curriculum appeals as much to girls as boys. Yet John Patten, the Secretary of State for Education, looks likely to make drastic modifications to the technology curriculum that would return it to the domain of boys. If the latest proposals from the Schools Curriculum and Assessment Authority become law, teachers will be dealing with a subject that is conceived around the acquisition of engineering knowledge and skills. We will have to devise projects that teach mechanical and electronic control systems, structures and ways of modifying materials. To achieve good grades, we will have to ensure that students know their facts.
Will we have time for a thorough investigation of need, and for learning to flow from this? The subject is being simplified and repackaged in male terms. This is partly due to intense lobbying from the Engineering Council and from teachers who are feeling overloaded. Traditional craft teachers feel unable to impart basic skills. More insidiously, some use the argument that knowledge is about facts, with learning achieved only through right or wrong answers.
But there is a different starting point, which underpins the present curriculum. This is that knowledge is constructed by individuals as they try to make sense of the world. Drawing on the insights of previous generations, children are able to forge and test their knowledge.
Yes or no answers do not always fit. Girls tend to score higher in essays than in multiple-choice tests and perform well on course work because they can explore the grey areas. Girls are sensitive to relationships and the effects of science and technology on relationships.
Products and environments, and the systems within which we operate, all play a crucial role in the way we interact. Technology must be conceived in the language of human interactions if it is to be truly accessible to all children.
The author is head of art, design and technology at Mount School in York.