'I'm a scientist and you're running your bath wrongly - this is what you should do'

Scientists have revealed why your bubble bath may be falling a little flat - and, more importantly, what you can do to run the perfect bath without using half a bottle of bubble bath for every dip. According to experts, squirting the bottom of your tub with bubble bath before the taps have been turned on is a common blunder. If you do this, you're not getting the most from your product and are essentially pouring unused bubble bath down the drain.

Instead, you need to squirt the liquid directly under a fully turned tap - but only when the water has started running hot. Professor Leif Ristroph, experimental physicist at New York University, told the Daily Mail high-pressure water from the taps is an essential ingredient for bubbles.

He said: "You need to provide a lot of agitation of some kind to whip air through the liquid, which is needed to make lots of bubbles quickly."

But if that still doesn't work the boffins have another trick up their sleeve. A spoon of baking soda into the bath will boost your bubbles.

"If commercial products do not work, try adding some baking soda," said Roberto Zenit, professor of engineering at Brown University, reports the Daily Mail.

Suddenly you will be enveloped in white clouds of foam. Adding a spoon of baking soda, also known as bicarbonate of soda, into the bath, which reacts to water by producing carbon dioxide gas.

Baking soda is a highly alkaline substance and can relieve irritation and pain from certain skin conditions, which is another boost to your bath, but it should not be confused with baking powder. Adding a little glycerine into the mix can also help with longer-living bubbles.

Glycerine is used in the food industry and also in personal care products to moisturise and protect the skin, but it can add a bit of strength and structure to bubbles so they don't pop as fast.

Dr David Fairhurst, a physics reader at the University of Edinburgh, said the hardness of water is another 'key factor' - but this depends on location.

In England, 'hard water', which has a high mineral content, is common in areas such as London, Kent, Sussex,Essex, Norfolk and Surrey, while, 'soft water' with a lower mineral content tends to be in Cumbria, Lancashire and Yorkshire. The harder the water, the fewer the bubbles.

"The minerals in hard water combine with the soap-like molecules in bubble-bath liquid, locking them away so they aren't available to stabilise the bubbles,' Dr Fairhurst said.

"Baking soda reduces the acidity of the water slightly which improves bubble lifetime."