A  Several large retail chains utilise various technologies to monitor customer habits, increase profit margins, and enhance product delivery. Retailers, it seems, are buying the idea that by watching customers while they shop – what might be called 'retail surveillance' – and redesigning their shops accordingly, they can get people to spend more.

B  One system, called Smartlane, has been successfully trialled by several major retailers. It has two elements: sensors by the doors count the number of people entering and leaving the shop, and sensors by the tills work out how fast the queues are moving and how many 'shopping units' – groups of people, such as families or couples, that make one transaction between them – are standing in each queue. All this information can then be used to predict how many tills will be needed up to an hour in advance and monitor average waiting times and queue lengths. In some cases, a queue longer than one shopping unit triggers the opening of another till. One British retailer said last year that the monitoring system had reduced waiting time for customers and helped to boost the firm's revenue.

C  This is not the only technology keeping tabs on shoppers. Another supplier of customer-monitoring systems uses dual-lens cameras, which are more accurate than single-lens cameras, in tracking and counting. Rather than monitoring queue lengths, however, the system, called BehaviorIQ, is used by retailers to gather data on where their customers go, how long they slow down to look at different products, and how they react to them. This information can then be compared with the store's transaction log to determine the effectiveness of store layout, product fixtures and other variables. In-store designs and marketing campaigns that work can be identified and worked on, and those that do not work can be replaced with something more profitable.

D  One of the largest customer-monitoring projects undertaken so far is PRISM (or 'Pioneering Research for an In-Store Metric'). The project involved the use of sensors at the entrances and exits and in some of the aisles of 160 stores across the US. These sensors recorded data on customer-traffic patterns, to which was added further information recorded by human observers. By comparing the resulting data with sales information, it was then possible to gain insight into shoppers' behaviour. For example, when observational data on the number of children present during a shopping trip was taken into account, the results were even more detailed: the PRISM results showed that although children took part in only 13 per cent of food-shopping trips, shoppers bought more when accompanied by them. Purchase of seasonal items was two and a half times more likely with children in tow but surprisingly there was no correlation found between the presence of children on a shopping trip and higher spending on sweets.

E  A further adaptation of this technology is VideoMining, which uses a combination of video cameras and software to capture and analyse thousands of hours of footage of customer behaviour. As well as providing information about customer behaviour, the firm's software can also determine each shopper's sex, age range and ethnic group with an accuracy of around 80 per cent, says Jeff Hershey of VideoMining. The system can even be programmed to detect the characteristic behaviour of shoplifters as they steal goods from places in the store. Inevitably, all this raises doubts about privacy. Counting customers with motion sensors as they enter a supermarket is one thing, but sorting them into social or racial groups using video analysis is another. Retailers respond that none of the footage or information about individual shoppers is stored and that customers are generally willing to give up some personal information if they feel they are getting some benefit in return.

F  Shoppers are not just being monitored by cameras and heat sensors, however; sometimes their speech is being recorded, too. Recordant, an in-store monitoring system operated by a company based in Atlanta, provides shop assistants with digital-audio recorders, to be hung around their necks, which record all their conversations with shoppers. At the end of each day the recording devices are plugged into special docking stations and the recordings are uploaded to Recordant's headquarters for analysis. Its software scans the recorded dialogue for particular words or phrases without the need for any human input, in order to provide accurate information on employee performance and customer behaviour. By providing precise measurements, the technology allows retailers to refine their employee training programmes. They can even programme the system to search for any mention of their competitors. Unlike systems based on video cameras or sensors, users of Recordant's technology are required to notify customers explicitly that their conversations are being recorded.

G  As useful as customer-tracking systems may be for protecting harassed staff or minimising shoplifting, however, their primary objectives are clear. In an age when traditional 'bricks and mortar' retailers face stiff competition from online merchants, any means they can use to get customers into their shops and buying as much as possible is seen as a worthwhile investment.

There is a recent movement in the world of food, in which chefs are collaborating with scientists to teach themselves the chemistry and physics of cuisine. Even academics are getting excited about the results. Colin Osborne of the Royal Society of Chemistry in London is enthused: 'Chefs are using unusual methods to produce exciting dishes that would be impossible without modern science,' he says.

You may wonder what's wrong with long-established culinary traditions. The fact is, many culturally ingrained cooking methods are less than perfect. Osborne gives the example of the common belief that frying meat seals in moisture, while researchers who weighed the meat actually found that moisture is lost in the process. Another example is the age-old technique of adding salt when boiling vegetables to raise the water's boiling point, thus cooking the vegetables faster. In fact, the amount of salt typically added does not raise the temperature significantly – or improve the flavour, since only a minuscule amount is absorbed.

Hervé This, director of the Molecular Gastronomy team at the French National Institute for Agricultural Research, spends much of his time trying to disprove culinary old wives' tales. He is empirically testing traditional beliefs about cooking and disproving the more absurd, tackling such questions as whether it's better to add vinaigrette to potato salad while the potatoes are still hot. 'The first modern chemists used kitchen equipment to do their experiments,' Hervé This explains. 'Since then, chemistry has undergone massive changes – but cooking methods have remained largely as they were in the Middle Ages.'

It's seriously important work, says Peter Barham, a physicist at Bristol University. 'If you understand what's going on in cooking, you'll be better equipped to improve it.' Barham contends that it's difficult to get good results from cookery books, because recipes are typically poorly written. In stark contrast, he notes, scientific papers are subject to peer review, whereby experts pore over experiments to ensure they can be accurately reproduced. Barham also collaborates with leading British chef Heston Blumenthal, proprietor of The Fat Duck, a restaurant in the south of England. The restaurant is widely regarded as one of the best in the world, serving delightfully unexpected dishes such as nitro-scrambled egg and bacon ice cream.

When Simon Campbell of the Royal Society of Chemistry bestowed an honorary fellowship on Blumenthal for creative applications of science to cooking, he said: 'The scientific community admires and respects the research that Mr Blumenthal has performed to harness cuisine to science. Through his inquisitive and innovative approach to food he has underlined spectacularly how chemistry permeates all aspects of texture, taste and smell.'

Such restaurants are part of the movement known as 'molecular gastronomy', an expression coined by physicist Nicholas Kurti, working in collaboration with Hervé This. Kurti once quipped that it is a sad reflection that we know the temperature inside the stars better than the temperature inside a soufflé*. Kurti and Hervé This devised the expression 'molecular gastronomy' during the 1980s to denote the science of 'culinary transformations and eating phenomena' and differentiate it from food science.

'Twenty years ago, the worlds of science and cooking were neatly compartmentalised,' agrees author Harold McGee, a top food science writer. 'There was food science: an applied science mainly concerned with understanding the materials and process of industrial manufacturing. And there was the world of domestic and restaurant cooking, traditional crafts that had never attracted much scientific attention.'

A lot has changed in the two decades since he published his influential book on the topic. In a revised edition, McGee says the book was 'riding a rising wave of general interest in food, a wave that grew and grew, and knocked down the barriers between science and cooking, especially in the last decade. Science has found its way into the kitchen, and cooking into laboratories.'

So what does the future hold? Rachel Edwards-Stuart is a graduate PhD student who is studying some remarkable food additives, including modified cellulose gels that solidify on heating and melt again as they are cooled. The idea is to make dishes that develop different flavours as they are eaten. Her other project is creating drinks that change flavour. 'The concept came from... Roald Dahl's children's book Charlie and the Chocolate Factory, where Willy Wonka makes a bubble gum that is a whole meal in one sweet,' she says. Unfortunately, Edwards-Stuart was unable to say more, due to a confidentiality agreement with the restaurant for which she conducts her research.

While Hervé This, Blumenthal and Edwards-Stuart are the pioneers, the next phase will be to bring science into kitchens at home. Already there are books that provide an insight into the wondrous chemistry that turns humble ingredients into cuisine. And as the movement grows it will not be long before we see laboratory test tubes, flasks and maybe the odd centrifuge on sale next to carving knives, rolling pins and pressure cookers.

* soufflé: a French dish made using beaten eggs