The developed world is quick to come up with hi-tech answers to problems. For most of the people on our planet, these are both impractical and too expensive. But “low-tech’’ solutions to problems can be both simple and ingenious. They make efficient use of local skills and conserve precious resources. This project is about technology that is:

* sustainable and environmentally friendly;

* often applied in the majority of the so-called Third World;

* developed in collaboration with the people it is intended to support.

Such solutions can be easily reproduced in the classroom.

MICRO-HYDRO

In the UK, we take electricity for granted. But in Nepal, only a tenth of the population has mains electricity. For villages in mountainous areas, falling water offers an opportunity for “micro-hydro” - the conversion of energy from fast-flowing rivers thundering down the Himalayan mountains.

The river is diverted through a turbine - a wheel with blades attached that is turned by the falling water. The turbine drives a generator, and electricity from the generator is available to village homes and businesses. Electric motors power machines to mill grain, or to remove the husks from rice. In the village of Ghandruk, every house has electric lighting, and one in five are able to use electricity to cook meals.

Electricity saves women the drudgery of milling grain by hand; it provides lighting in houses, thereby extending the day and improving quality of life; it saves trees, and has reduced the time and effort once spent on collecting wood for fuel.

THINGS TO DO

In Nepal, a generator has been developed that produces electricity by running an electric motor backwards. Children can model this. For example:

* Connect the terminals of an electric motor to a low voltage bulb with two wires. Wind a thin, strong thread around the pulley of the motor. Pull it sharply to spin the motor and the bulb will light.

* Make a turbine wheel using a washing-up bottle. Cut the bottle in half and cut angled slots into the cut end. Bend these out to make vanes. Push a piece of wire through the bottle nozzle to form an axle. By holding the turbine under a running tap, the water will spin it. Explain that if the turbine was linked to a reversed motor, it would generate electricity from the falling water.

There are links to key stage 1 and 2 electricity work in science.

PEDAL POWER

The bicycle is an efficient and low-cost form of transport. By use of a simple hitch - a hook with a ball on one end bolted to the back of the bike - it can be used to pull a lightweight trailer. This was the conclusion of a designer who worked with Indian families to develop an original form of basic transport. The trailers are built by local craftspeople.

Indian roads are often rough and unsurfaced. But a tubular steel trailer on bicycle wheels can survive most of them. Whee the road is rougher or the load is greater, rickshaw wheels can take the strain. The bicycle trailer can carry goods to market, take medicines to isolated villages, or become the basis of a mobile shop. A heavyweight trailer can transport full milk churns.

Farmers and small business owners can pay for the trailer with their increased profits. They, their customers and families can all benefit from the extra income and the wider availability of produce.

THINGS TO DO

Children can design a trailer for a special purpose. It might be to carry a special product, to become a mobile resource, or to be the basis of a new business. For example, they might create a trailer for a vet, the police or a travelling salesperson; to carry clothes or books, or a precious or delicate load.

Almost any model will run so long as the wheels are round. You can buy wheels in card, wood or plastic from technology suppliers or you can use large tap washers, lids and tops of all kinds, or even slices of potato cut with a round pastry cutter! Fix the wheel to the axle so that axle and wheels turn together. Gluing a couple of clothes pegs to the trailer makes good bearings - run the axles through the jaws of the peg. Children can mix and match axles and wheels this way.

Using recycled materials and card, the children can build, finish and test their own prototypes.

There are links to the technology curriculum at both key stages; and to other areas of geography, history and citizenship.

* FAST FOOD

Our towns and cities are full of fast-food outlets. But street foods are not unique to the developed world. Mobile kitchens line the pavement in Manikganj, a town of 38,000 people in Bangladesh. Here, the street food business employs hundreds of people and has a turnover of two million US dollars a year.

Bangladeshi fast food includes samosas made with vegetable, coconut and spices (shingara); puffed rice balls (mooa); and a savoury spice mix called chana-chur. Shaheen makes shingara. She sells breakfast to people on their way to work. She buys all her ingredients from the market and uses a traditional recipe that she learned from her mother. She spends her profits on rent and food for her family.

Fatema Begum, from Zanjira town in Bangladesh, has set up a fruit-processing centre making jams, jelly, pickle and sauce. Her centre employs 50 women who are trained in food processing.

THINGS TO DO

Children can design a healthy breakfast food.

* Give them oats, wheat flakes, and unsweetened corn flakes as a staple, then let them more sparingly add flavour, texture and appearance enhancing foods, such as dried fruits, nuts and kernels.

* Ask pupils to make a mix that would appeal to a younger sister or brother; to test their new cereal by asking friends to taste it and give their opinion; to improve their design by altering proportions of the ingredients; and to name, package and market their idea. Links to technology, PSHE, sustainable development and citizenship.