Ellen Moye

Today is St Patrick’s day! This cultural and religious celebration honours the death date of the patron saint of Ireland. It’s purpose, traditionally, is to commemorate saint Patrick and the arrival of Christianity in Ireland, although more recently it is a day of celebrating Irish culture in general. People dress in green, Christians attend church services and the restrictions on food and drink imposed by Lent are lifted. Perhaps because of this, drinking alcohol has become what the holiday is notorious for, with celebrations spreading across the world.


Image Credit: Wikimedia Commons

If you do choose to celebrate the day with a tipple, what stereotypically Irish drink would you be most likely to choose? Of course the mind springs instantly to a cool pint of Guinness, the Irish dry stout first brewed in Dublin in 1725. Guinness is a legendary drink, not only for being the best selling drink in Ireland but also for its gravity defying bubbles! After your local bartender pours a pint of the dark stuff (and if it’s only your first pint!) You might notice that the foamy white bubbles settle downwards rather than rising to the top.

In a beer or a fizzy drink, carbon dioxide is added to the drink at a high pressure and when you release this pressure by opening them, it begins to escape, creating bubbles and making the drink fizzy. The bubbles are less dense than the liquid and so flow upwards to release the gas at the surface. But in Guinness, the bubbles defy these physical laws and flow downwards. This sinking bubble mystery puzzled everyone: from the people in your local pub, to physicists in the lab. A scientific paper published in 2012 finally provided the answer.

The solution appears to be a combination of the shape of the glass and the type of bubbles in Guinness. The bubbles in Guinness, unlike in bitter, contain nitrogen as well as carbon dioxide. The diffusion of nitrogen is very different to the diffusion of carbon dioxide. The dynamics of the fluid in the glass are influenced by the diffusion of these gases. The other ingredients in Guinness also coat these nitrogen bubbles and influence their velocity in the liquid.

The largest surface area is the flat middle of the pint glass, as opposed to the curved sides. Therefore, comparatively, more bubbles will rise from the middle. Here, the Guinness bubbles in fact do flow upwards and in doing so they drag the liquid with them. This upward rush of liquid from the centre will then move out and flow down the walls of the pint glass dragging the bubbles down with it. It is similar to the way a water fountain works. This creates the illusion from the outside that the bubbles do, in fact, flow downwards. This knowledge has informed industrial processes and the food industry.

But why does the Guinness contain nitrogen? It has a low solubility in liquid and works to displace carbon dioxide, giving a unique, creamy and frothy head. Draught Guinness is dispensed from kegs pressurised with nitrogen to achieve this but it does not translate well into canned beers.

To overcome this, the scientists at Guinness developed a “widget”. This contains nitrogen and when the pressure in the can is lowered by opening it, the widget releases additional nitrogen. This successfully mimics the delicious head on a draught Guinness. In 2006, Guinness also introduced another option, a “surger” to sit under a pint glass and send out ultrasonic waves to drive bubbles out of solution and add to the creamy froth.

The head is bright white and more aesthetically pleasing than foams that appear on bitters. This is, again, thought to be down to the nitrogen in the bubbles. The bubbles are smaller than those of just carbon dioxide and when the light hits them, it scatters equally and the foam appears bright white to our eyes. Everyone can remember back in school being asked to sort various objects into the categories of solid, liquid and gas. However, Guinness foam complicates this classification as it satiates the requirements of all three!

Therefore, the packing of the particles in the foam of beers was also a big question. 2D foam always joins together in a honeycomb structure, however, 3D foam is much more complex. Researchers in trinity college, Ireland, discovered using Guinness that the 3D structure of foam is comprised of two slightly different types of 14-sided particles binding together in a lattice. This discovery is honoured in a statue in the university and inspired the design of the aquatic centre in the 2008 Beijing Olympics.

So where will you be raising your pint of Guinness this St Patrick’s day? Sheffield has some great options including a St Patrick’s day specials at the Students’ Union, the Guinness Tent of Fargate, the Uni vs Hallam Paddy’s Day bar crawl on Carver street and ‘Nice Like Potato’ at the Harley. Or if you want to go further afield; then the Guinness factory in Dublin is always a great trip where you could learn even more about the famous Irish stout.

Before you hit the town don’t forget to check out; for the government guidelines on drinking.

Happy St Patrick’s Day!

Would I Lie To You?

Ellen Moye

Are your pants on fire? Because Dr Robert Feldman, Psychology professor at the University of Massachusetts, says that they are. His studies into lying conclude that everyone lies, and at an alarming rate too! In fact, on average people will lie two to three times in a ten-minute conversation alone, a statement that gives stead to previous estimates that humans are lied to at least 200 times a day.


Image Credit: Wikimedia Commons

The University of Portsmouth found children could already learn and utilise deception techniques by age six months, pretending to laugh and cry for nothing other than attention. Dr Gail Saltz, a New York psychiatrist, says that once children reach the ages of four or five they have a firm enough grasp on the use and power of language to begin to lie properly. She notes that these first lies are merely a test: to see what can be manipulated in their environment and to what extent.

So how, as children, do we learn to lie?

The mechanisms behind how children learn to lie are still shrouded in mystery but research suggests that lying is a strategy used by young children as a way of developing independence. Children observe from their parents that there are things that their parents keep from them and thus begin to create secrets of their own. Thus they learn lying and secrecy from their parents.

At a young age lying is healthy and normal but as the child grows and the brain develops, normal development dictates that lying should begin to abate. This is in order to fit in with a society where lying is generally taboo.

So why do we lie?

Lying is a reflex. In fact, in one of Feldman’s studies he asked subjects to watch a filmed conversation they had just had with a stranger and point out any inaccuracies in what they said. Many of the subjects were surprised to find that they had told lies, initially claiming themselves to have be 100% accurate in the conversation.

Feldman would say that lying is an evolutionary trait. It has evolved as a good mechanism to “preserve our privacy and protect others and ourselves from malice”. This is shown in everyday life in the harmless white lies that people tell. For example, telling your friend that you like their new trainers when you wouldn’t be seen dead in them yourself.  Feldman would say this protects our friend from malice and thus, they remain our friend, which is advantageous for us.

Most would agree a white lie about a pair of trainers is fairly harmless, but where do we draw the line? When is lying OK and when is it not?

When a person feels compelled to lie consistently and with seemingly nothing to be gained from that behaviour is when society tends to draw the line. This trait, known as pathological lying is self-deprecating and although not a mental health problem itself it can be seen as a symptom of various personality disorders and psychopathy.  Causes can include; dysfunctional families, learning disabilities and substance abuse and pathological lying can cause the perpetrator to be ostracised as it can create relationship, financial and legal trouble.

Whilst pathological lying can be detrimental, lying from a young age is simply a healthy step in development.

Why Do We Change Height Throughout The Day?

Ellen Moye

It turns out that the majority of us undergo a measurable height change from waking up to the end of the day. While for most this change goes by mostly without notice, others can experience a shortening in the scale of inches.


Image Credit: Flickr

The measurement of two brothers in 2001 was performed by Tillmann and Clayton, two experts in children’s development from the University of Tartu. They quantified the height loss and found that most of the height “gained” overnight is thought to be lost in the first 3 hours of our day and maximal height loss is achieved by around 3pm.

The average change in height throughout the day is thought to be around 19mm. This is mostly attributable to changes in the height of our intervertebral discs. Our spine, as one might expect, is in fact not a long continuous bone. It is composed of 33 small bones called vertebrae. Spongy intervertebral discs lie between adjacent vertebrae in the spinal column. They have a role as shock absorbers preventing damage to the vertebrae themselves.

During sleep the loading (the amount of stress or pressure) on the spine is reduced. There is nothing preventing them from swelling and so they begin to absorb fluid and increase in volume. As the volume of the discs is increasing, they are of course also increasing in height. When we stand up and go about our daily tasks the loading on the spine is increased. The fluid will then begin to be expelled from the disc and it will decrease in size. Therefore, throughout the day the fluid content and height of the discs is variable. This leads to slight variation in height throughout the day.

These changes throughout the day may have a use in the diagnosis of lower back pain and sciatica. The time of the onset of symptoms and any changes in their severity throughout the day may be able to act as an aid in diagnosis. Lower back pain can be caused by a variety of problems including nerve irritation and degeneration of the intervertebral discs. Sciatica is pain from the lower back going down the leg. In 90% of cases it is due to the slipping of an intervertebral disc which will then push on any of the nerves that run from the back into the leg.

Research into using changes in height to aid diagnosis of these conditions was performed in 1990 by a group of bone specialists. They used dead bodies to investigate the effects of loading on the properties of intervertebral discs. They found that with increased loading, amongst other effects, disc prolapse becomes less likely and could explain why previous studies have found that ‘first episodes’ of back pain occurred in the early part of the working day and mine workers sustain spinal injuries more commonly in the morning.

Also, since different structures are more heavily loaded throughout the day, the time of onset of a patient’s symptoms, and any changes in their degree of severity over the day may help us to understand how their condition is working to affect the spine. For example, if most pain is felt in the morning when bending then the issue is probably due to the intervertebral disc. This is because most pressure is put on this structure in these conditions.

They also note that differences in lifestyle will affect the change in height. For example, a heavy manual labour job will induce a quicker change in height than a more sedentary lifestyle. In effect, lying on the sofa all day could make you taller!

Are Mobile Phones Safe?

Ellen Moye

Most of us would agree that a mobile phone is an essential part of our lives today. We use them not only for texting and calling, but also as a calculator, a weatherman, a games console, a compass, a camera, a watch and to access the internet. In fact, some of you may be reading this article on a mobile phone!

But how many of you have stopped to think about the possible dangers of this little, radiation-emitting box you’re willing to hold so close to your head?


Image Credit: Pexels

The World Health Organisation takes the potential dangers of mobile phone transmissions very seriously, because of their widespread use. Their potential effects on human health have been the subject of many a scientific study with most of them looking at the potential links with cancer.

So far, most research has found mobile phone transmissions (both from the phone itself and from the telephone masts) insufficiently powerful enough to cause cancer.  However, some suggest that this little amount of radiation may interact with natural electrical oscillations in the body and still have detrimental effects including; headaches, sleep disturbances, epileptic fits and tumours. Research remains inconclusive, and, thus, mobile phones remain classified as a “possible carcinogen”.  

The International Agency for the Research on Cancer comments that any link that is found between mobile phone use and cancer could also be explained by a common factor. For example, someone that lives a sedentary lifestyle is more likely to get cancer but also more likely to use their mobile phone a lot. The cause of cancer could be the sedentary lifestyle, rather than the mobile phone use.

Other, potential health effects that have been investigated include; an increase in reaction time, effects on the brain’s ability to absorb sugars near the site of the mobile phone antenna, interference with pacemakers and effects on sperm motility and quality. Although, most of the studies that lead to the above observations are hard to replicate and we cannot be sure that the results are not just down to coincidence.

Social effects are also apparent. With the increased use of the mobile phone people are more contactable than ever. We can be contacted by our spouses at work and our bosses on the weekends. This increased contact may explain the rise in telephone phobia. The second, most obvious social effect is using mobile phones at inappropriate times. We’ve all seen the adverts and we all know the dangers of using a mobile phone when driving. Mobile phones provide a distraction that is not always welcome and can have devastating consequences.

It’s not just human health that is under investigation; visual pollution and environmental effects are also very real problems related to mobile phone use. The reason most people protest the construction of a mobile phone mast is not the potential health risks but the blight to the landscape. Masts are big, metal and – in most people’s opinion – ugly.

The potential environmental effects are as vast and varied as the potential health effects. There are potential problems with the mobile phones themselves, in that they contain heavy metals which, if disposed of incorrectly, can be introduced into the environment and affect the food chain. There may be problems with the telephone masts too, as studies are being conducted into the effects on surrounding wildlife and tree density. The effects on the environment, like the effects on health, are not certain and require further research.

Mobile phones have not been in popular use for very long they are a recent invention and we cannot be sure of the consequences of long term use. No one generation has lived a full life with regular mobile phone use and with some scientists suggesting the risk is amplified in children how can we be sure that there will be no effects in someone who has used a mobile phone from a young age when they reach their 60’s or 70’s?  

One thing is clear, though, driving whilst fiddling with your mobile phone is a real danger.

NHS recommendations for mobile phone use:

  • Only make short calls and do not use it more than necessary.
  • Children should only use mobile phones for essential purposes.
  • Keep your mobile phone away from your body when you are not using it.
  • Only use your phone when the reception is strong.
  • Use a hands-free kit to keep your phone away from your head whenever possible.

Department for Transport guidelines for safe use of mobile phones in cars:

  • It is illegal to use a hand held mobile phone when you are driving.
  • Keep your mobile phone switched off when you are driving.
  • If you need to use your mobile phone, stop in a safe place.
  • Avoid using a hands free device – they can still be distracting.