Science

[Watch] How and why do freckles appear?

[Watch] How and why do freckles appear?

nao

Another great question this week, this time sent in by seven year old Daniel, who lives in Singapore; Daniel would really like to be a scientist when he grows up, but I reckon he already is one as he loves asking questions and finding out lots of facts about science and nature. In fact, Daniel is a regular to this blog, he often is the first to work out the Mystery Creature of the month!

Daniel’s question is…

How and why do freckles appear?

Many of us have freckles, Daniel has them too, in fact he appears IN the video as the freckle model 🙂 If you would like to know a little more about freckles (I bet you do!) just watch this video below!

Freckles are pretty common, especially in people with fair complexions, but before we look at how and why they appear, let’s take a closer look at what they are?

What are freckles?

Freckles are small spots on the skin, they are usually tan or light brown in colour. Unlike moles or some birth marks, freckles are flat on our skin. They are completely natural and harmless.

We are used to seeing them on peoples’ faces but they can be found all over the body.

They often become more obvious or more abundant when we expose our skin to the sun and that gives us the first clue as to why they appear.

freckles

Natural Sun-screen

Freckles are the result of a natural colour (or pigment) called melanin produced by the body to protect the skin against the harmful rays of the Sun.

This process is called photoprotection and this is how it works…

When UV rays of light from the Sun hit our skin they  trigger certain cells in our body to make more melanin.

The cells that make the melanin are called melanocytes.

melanocytes and freckles

 

The melanin is sent to the outer layer of our skin where it absorbs these harmful UV rays, protecting the skin cells (and the cells’ DNA) from their damage.

Usually melanin is distributed evenly around the parts of the skin that are exposed to the sun, causing our skin to tan.

When melanin is distributed evenly we tan

Sometimes though the melanin clumps together in areas, forming little dark spots that we call freckles.

When melanin comes together in small areas of skin we get freckle spots

So basically, melanin is a little like our bodies’ natural sun screen… which kind of makes freckles like natural sun screen spots I guess.

Who gets freckles?

So do only fair skinned people get them? No, that’s not so. There are probably a lot more people with fair complexions with freckles, and freckles tend to be more noticeable on fair skinned people, but people with all types of skin tones can get them too.

Freckles can appear on all skin tones

Freckles can develop on all skin tones

Freckles tend to run in families, so if your parents have them there is a good chance you do too. The tendency to get freckles is genetics… and is connected to a gene called MC1R.

So remember, freckles are natural and harmless. They are just a sign that our body is taking care of us and keeping us safe.

A big thanks to Daniel for sending in this question; if you have a question you would like me to answer just leave it in the comments below or sent it to me by email (drhowsciencewows@gmail.com).

 

The science of elasticity, energy and rubber

The science of elasticity, energy and rubber

nao

Energy is a great subject in science. It covers so many things and I have many other aspects that I hope to share with you soon but one thing that explains energy so well is a simple rubber band; it can demonstrate elasticity, kinetic energy and potential energy and it great to use in some really cool experiments. Here are just a few short facts on the topic.

What is Elasticity?

Elasticity is the ability of an object to return to its original size and shape after it has been stretched or squeezed.

When we pull an elastic object we are applying a force on it called a stress. If we apply too much stress to an object it will eventually reach a limit called its elastic limit.

When an object is pulled beyond its elastic limit is cannot return to its original shape.

All objects will eventually lose their elasticity due to wear and tear, friction and stress.

Potential and Kinetic Energy

Potential energy is energy stored within something. Kinetic energy is energy in motion.

If we take the example of stretching a rubber band…

When we use force to stretch an elastic object, such as an elastic band we are filling it with potential energy. When we let go of the rubber band and it springs back to its original shape, the energy released is Kinetic Energy.

Did you know… kangaroos and other animals use the combination of potential and kinetic energy to save energy while jumping and springing?

Rubber

Rubber is a material that has very good elasticity. It is a polymer, made up of a long chain of repeating molecules, that can be easily stretched and bent.

Rubber exists in both a natural and synthetic form; the natural form is latex from the sap of rubber trees.

A bit of history

The ancient Aztec and Mayan civilisations are thought to have been the first to discover and use this natural rubber. They used it to make balls for sport and rubber shoes, although the quality of this rubber was sensitive to heat and cold.

Columbus is credited with bringing rubber to Europe.

In 1839 Charles Goodyear discovered that he could stabilise rubber by mixing it with sulphur at high pressure; he called this process vulcanisation.

When Goodyear died in 1860 he was completely impoverished due to constant legal costs regarding his rubber patents.

Did you know… the largest rubber band ball ever made weighed 4,097kg and was made using 700,000 rubber bands?

 

An experiment to try

Want to try an experiment that combines rubber, elasticity and kinetic and potential energy? Why not make a catapult? Or use elasticity to launch a paper plane. You’ll find out how, and a lot more of the science behind these experiments in this post!

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A new venture

This article originally appeared in Science Spin magazine. Although the magazine is no longer in print I am delighted to be sharing some science facts and experiments in a new venture… you’ll find my new SCIENCE FOR KIDS page in each edition of Easy Parenting Magazine. I share one of our favourite experiments in the April/May edition, currently in shops. Take a look…

 

 

[WATCH] How do planes stay up in the air?

[WATCH] How do planes stay up in the air?

nao

This great question was sent in by six year old Cathal, who can sometimes be found over at Bumbles of Rice blog; Cathal has a really scientific mind and is always asking him mum lots of questions. Sometimes she sends them on to me, which I really love.

I thought that Cathal’s question was a great excuse to try out another whiteboard video, I hope you like it Cathal and keep those questions coming!

How do planes stay up in the air when they are so heavy?

It is a common question and one that we all want to know; especially if we are sitting on a plane about to take off! So if you want to know how planes stay up in the air, make sure you watch this video below to find out!


Planes are pretty big machines; the world’s largest passenger plane is the Airbus A380 which can weigh as much as 560,000 Kg.

That is a lot of plane to get into the air and keep it there.

The largest passenger planes is the Airbus A380, weighing in at a massive 560,000 kg

Even smaller planes, with all their equipment and passengers and baggage, are pretty heavy things, so how do they stay in the air?

We think of air as being very light as we move through it all the time. But remember air is made up of tiny molecules that can actually be really strong too, there are lots of them and they can move together with quite a force.

Air can be so strong it can blow over people, cars and even buildings when it moves very fast, like a tornado!

It can be strong enough to hold a plane in the sky too, but we don’t need to create extreme weather conditions to do so, we just need to consider four important forces, and get them just right.

The four forces are LIFT, GRAVITY, THRUST and DRAG!

These four forces act in different directions… Lift pushes the plane up, Gravity pulls it down, Thrust propels it forwards and drag pushes it back.

The four main forces acting on a plane in flight are lift, gravity, thrust and drag

If we can get these four forces balanced just right, we can get a plane in the air, and keep it there.

Lift

Let’s consider LIFT first, and to do that we need to look at the shape of the plane, and in particular… the wing. We call the wing shape an aerofoil, it is curved at the top, like this. This shape is designed to make air move faster over the top of the wing than below it.

When air speeds up its pressure decreases (this is in keeping with a law of physics known as the Bernoulli’s principle).

Bernoulli’s principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure

When the air pressure on top of the wing is less than the air pressure below the wing it creates a force called LIFT which pushes upwards on the wing.

Gravity

GRAVITY is the force that pulls the plane towards Earth; it keeps it on the ground. In order for the plane to get into the air, the LIFT force needs to be greater than the force of GRAVITY.

To get enough air moving over the wings of the plane it need to be travelling through the air at quite a speed.

Thrust

We use engines to propel the plane forward using a force called THRUST! The more thrust is generated, the faster the plane goes and the more air travels around the wings. LIFT increases until its force is greater than that of GRAVITY and the plane takes off into the air.

So far we have covered three of the four forces… LIFT, GRAVITY and THRUST. There is one more to consider… DRAG.

Drag

DRAG can be described as a force that acts against a moving object. So, in this case, the plane is being propelled through the air, by the force of THRUST, but that air is moving against it, and creating a DRAG force.

THRUST moves the plane forwards, DRAG pushes it backwards. In order to keeps the plane moving in the right direction, THRUST must be greater than DRAG. Planes are designed to be streamlined – to allow air pass around them with the least amount of resistance – to reduce DRAG.

A bit of Balance

So a plane can stay in the air once the four forces… Lift (up), Gravity (down), Thrust (forward) and drag (backwards) are kept at the right balance.

Essentially the plane needs to have no net force acting on it, which means that each of the forces balance each other out.

Newton’s Law of Motion

Let’s consider one more law … Newton’s Law of Motion which states that an object at rest will stay at rest and an object in motion will stay in motion, once there is no net force acting on it.

Newton’s first Law of Motion which states that an object at rest will stay at rest and an object in motion will stay in motion, once there is no net force acting on it

What this really means is that, once all these four forces are balanced, the moving plane, will stay moving… in the air… in flight!

Which is just the way we like it!

A big thanks to Cathal for sending in this question; if you have a question you would like me to answer just leave it in the comments below or sent it to me by email. 

Why does my tummy rumble?

Why does my tummy rumble?

nao

I’m back with another great question this week, send in by Sarah, who wants to know …

Why does my tummy rumble?

It is all explained in this short video, just click to play (or, if you prefer, you can read the answer below).

While we sometimes find the noise a little embarrassing it is actually a really natural, and essential thing and shows that our bodies are working correctly, but why all the noise?

Let’s take a closer look!

The noises come from our digestive system, which is basically a long tube that stretches from out mouth to our anus! It usually comes from our stomach or small intestine.

The wall of this tube is mainly made up of muscles, called smooth muscles, which move in a certain way to push food through the system. This muscular movement is called peristalsis and this is how it works…

A small area of muscles contract, a bit like squeezing a ring around a part of the tube and this pushes things like foods, liquids and gases forward a little; then these muscles relax and the muscles in front of them contract and so on, pushing food and other content down the tube with each contraction.

Think about squeezing toothpaste from a tube!

The noises we hear are due to the movement of food, liquids and gases down the digestive tract. We associate the noise with an empty stomach, or being hungry, but the sounds are made when we have food in our system too. We often don’t notice them as the sound is dulled down.

When our digestive system is empty the noise is a lot louder.

It makes sense that peristalsis happens when we need to pass food through our digestive system, but why all the activity when our stomach is empty? Well this is the result of something called the Migrating Motor Complex or MMC for short!

This usually happens when our stomach and intestine have been empty for about two hours; a type of electrical pulse is triggered and this causes peristalsis through the digestive system. This serves a type of cleansing function; it clears any pockets of leftover food, mucus, bacteria and other debris from the stomach and small intestine.

The MMC response is usually triggered when our digestive system has been empty for about 2 hours

The MMC response is triggered every 90 to 120 minutes, until the next meal is eaten. It does tend to quieten down a bit while we sleep and then ramp up the activity again when we waken, which is why we often have gurgling tummies in the morning.

I hope you enjoyed this short explanation and video; Do let me know in the comments below and as always, if you have a question you’d like answered just leave it in the comments below! 

Are all raindrops the same size?

Are all raindrops the same size?

nao

As you know, I love receiving your questions and I am always thinking of different ways to answer them. Some you will find in my regular column in the Irish Examiner, some I answer here on the blog, in written, video and info-graphic form.

Here is something a little bit different and I am hoping to make it a regular thing, so please let me know what you think and keep those questions coming!

Are all raindrops the same size?

In order to answer this question we need to first understand how raindrops are formed. And that story starts right down here on Earth. We have lots of water in the form of rivers, lakes and seas and when this water heats up it changes into a gas, called water vapour which rises up into the air.

The sky actually has lots of bits floating around in it – like dust and smoke particles. The water vapour tends to form tiny droplets of water around these little specks of dust and smoke and these droplets come together to make clouds.

At this stage the tiny drops are light enough to stay in the sky, but, as the cloud fills up with more and more of them they tend to start to bumping off each other and as they do they join together to form bigger droplets. Eventually they get so big and heavy that they can no longer stay in the cloud and they drop down towards the Earth as rain.

A water droplet needs to be at least ½ mm in diameter before it will fall as a raindrop.

Depending on how many droplets have joined together to make that raindrop, we already have drops of different sizes falling from the clouds.

What shape doe you think the raindrops are? Teardrop shaped maybe? No, not at all! Although raindrops are usually depicted in this teardrop shape they actually start off as nice round spheres. They have lots of forces acting on them, like surface tension which acts on the surface of the drop keeping it in that nice round shape.

As the rain drops fall they experience other forces too like air pressure. As it pushes from below and above the rain drops get squished into sausage like shapes until they eventually split into a number of small drops of various sizes and these are what fall to the ground.

So, are all raindrops the same size? Definitely not!

And they are not all teardrop shaped either.

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A big thanks to Ewan for sending in this question. Remember to keep sending in your questions. You can leave them in the comments below.

I’d love to know what you think of this video, there are lots of improvements I want to make and I’d love your comments and feedback.

 

The perfect pancake formula

The perfect pancake formula

nao

We are big fans of pancakes in this house; I’m pretty casual with my batter making at this stage, I throw a few things into a bowl or blender, a bit of a mix, into the pan, quick flip and hey presto! It seems I am going about it all the wrong way. There are formulas that I should be following, such as…

  1. The batter formula

If you take your pancakes seriously, you’ll want the appearance to be just right. It’s not just luck or habit; it is all about the flour to liquid ratio, according to a group of researchers at University College London.

The thickness of the pancake determines the way the water in the pancake is released during cooking and ultimately determines the overall appearance of the finished product.

The experts devised a formula…

Mixture (ml) required per pancake : (D² x T x π) / 4

Total mixture (ml) required: (D² x T x π) / 4

… where D is the diameter of the pancake pan and T is the thickness that you want your pancakes!

And believe it or not, this pancake study has medical benefits too: the team are using what they learned to create better surgical methods for treating glaucoma, which is a build-up of pressure in the eyes caused by fluid.

pancake17

  1. The perfect batter calculator

If this all sounds a bit too complicated then don’t worry, maths students at the University of Sheffield have taken this formula and generated a calculator that does all the maths for you. All you need to do it type in how many pancakes you want, how thick you want them and how wide your pan is and voila, you get an exact recipe!

  1. The super formula

If you like your pancakes with some extra maths then don’t worry, there is a formula for you too, but hold on to your whisks, this one is pretty tricky!

100 – [10L – 7F + C(k – C) + T(m – T)]/(S – E)

Apparently, the closer you get to 100, the better the pancake.

L is the number of lumps in the batter; C is that consistency.

F stands for the flipping score, k is the ideal consistency of the batter and T is the temperature of the pan.

M is the ideal temp of pan is, S is the length of time the batter stands before cooking and E is the length of time the cooked pancake sits before eating.

Are you still with me? If not don’t worry. If everyone in your house is happy to eat your usual offerings then I’d go back to the old reliable. Me? I’m taking my inspiration from this post and I’m going to add some colour and sprinkles… without a calculator in site.

Whatever way you make your pancakes today, I hope you enjoy 🙂

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If you want to know a little more about your pancakes, from history, to ingredients, to science, check out my post over on Headstuff.org today!

How do snails get their shells and can slime mend a broken heart?

How do snails get their shells and can slime mend a broken heart?

nao

It is all about snails here this week; snail questions, bad weather and midterm break. I was planning a written blog in response to all his questions, but, spirits were high this morning (in the kids, not me!) so writing time was limited. Instead we went for something a little different and if you like it, I think it could become a regular feature.

We made a little video, the snail questioning one and I. So go get a cuppa and settle down for five minutes with us… it’s time to TAKE FIVE!

So what do you think? We hope you liked it, let us know what you think in the comments below and, if you have a question you’d like covered in a TAKE FIVE video, let us know!

Have a great weekend!

Why do we lie?

Why do we lie?

nao

I watched a great documentary on Netflix* recently all about lying… it is called Dis(honesty): the truth about lies and I would highly recommend it.


It really got me thinking about lying, why do we do it, what would happen if we don’t and is it a uniquely human activity?

First off, we all do it! If you are shaking your head in disagreement, then you’ve just lied too! Sometimes we do it for good reasons, sometimes just to save our skin, but we all lie from time to time. So why do we do it and is it a purely human activity?

WHY DO WE

We lie for a number of reasons, it may be a little white lie to make someone feel better or it might be a big lie for our own gain, or to save our skin!

Many of the lies we tell are to present a better side of ourselves; make ourselves appear a little nicer, a little smarter, or a little more popular. We don’t often even recognise these lies, we don’t realise we are doing it – we are lying to ourselves!

On a base level, we probably lie because evolution has shown us that it works to our benefit and the benefit of society. As our social connections have developed, so too have our abilities at lying. It is actually a valuable tool to have and brings with it many advantages. Lying is a sign of intelligence and is considered a complex cognitive skill.

Different types of lies and liars

There are different types of lies and different categories of liars! There are the little white lies that we all do, usually for social acceptance or compliance. There are lies of exaggeration, usually of little harm either;  and then there are the bigger lies that are often more serious and come with a lot more consequences if found out.

There are also different types of liars. We are all contributors to the pool of common-or-garden, everyday liars, but things get more serious when we look at the compulsive or pathological liar.

Compulsive liars tell lies as the norm, it is an automatic reflex and it takes a lot less effort for them than telling the truth does. Pathological liars tend to take it one step further; they lie for their own gain, with little thought to the consequences of their lies, for either themselves or others.

What happens in our brains when we lie?

Lying is a complex process; in order to do it our brains must focus on two opposing pieces of information at the same time: the truth and the lie. If we want to process or deliver a lie we need to believe that it could be true. The brain has to work much harder to lie than to tell the truth. Activity in the prefrontal cortex (at the front of the brain) has been shown to increase when a person lies. This is the part of the brain involved in decision making, cognitive planning and problem solving.

Usually when we tell a small lie, for personal gain, we feel bad. These emotions of regret and guilt are controlled by a part of the brain called the amygdala. However, the more we lie, the more we desensitize the amygdala so that it produces less of these bad feelings.

Studies on the brains of pathological liars show that they have about 25% more white matter in their prefrontal cortex, suggesting more connections between different parts of the brain. However, they also have about 14% less grey matter, the part that can help rationalise the potential consequences of each lie told.

No man has a good enough memory to be a successful liar- Abraham Lincoln

Do other animals lie?

Yes some do. One famous example that my children love to hear about is of Koko the gorilla. Koko is renowned for her sign language abilities, with an impressive vocabulary of more than 1000 words. Koko has a pet kitten that has come in handy for more than just cuddles and companionship. One day Koko tore a sink from a wall in her enclosure. When her carers returned and asked what happened, Koko signed ‘the cat did it!’

Koko The Gorilla2

When do we start lying and how often do we do it?

Some scientists believe that we begin the act of deception as young as six months old! This usually starts as fake crying, or smiling, to get attention. At that age we don’t do a very good job (although it is probably quite cute and amusing to watch) and we likely do not do it as a conscious lie.

By the age of two however, we have put in a little more practice and can deliver an outright lie with more commitment and conviction.

Adults are so good at lying that they can often lie even to themselves; on average, adults lie about 10 times a day and we can throw about three lies into a short conversation with a stranger, without even knowing we are doing it.

Are there ways to spot a lie?

Some of us are better liars than others and there is no detection system, including lie detectors, that work for all. However, many of us amateurs give away some tell-tale signs when we are lying, such as…

  • We make and keep direct eye contact (contrary to common held belief)
  • We keep our bodies very still, but we may…
  • jerk our heads a lot
  • We give more information than is necessary
  • We touch or cover our mouths with our fingers
  • We breathe at a more rapid rate
  • We cover vulnerable parts of our bodies, such as the throat, head or chest

Interestingly, we are better at lying when we lie for altruistic reasons than for our own good and these lies are more difficult to detect.

So that is the low-down on lying, and not a word of a lie 😉

Have you any facts or stories to add? I’d love to hear them, just leave them in the comments below.

*Disclosure: As a member of the Netflix Stream Team I have received a years subscription to Netflix, free of charge, and an Apple TV, for streaming purposes. As part of Netflix Stream Team I will be posting monthly updates on what we are watching and what is on offer.  All opinions expressed will be my own.

What would happen if we had no moon?

What would happen if we had no moon?

nao

What would happen if we had no moon?

That was a questioned posed by one of my kids this week. It lead to lots of discussion and interesting debate until finally we were talking about werewolves!

moon

 photo credit: kendoman26 Not Quite There! via photopin (license)

Firstly, lets consider how the Moon got there in the first place.

The Moon is approximately 4.51 billion years, about 60 million years younger than the Solar System. It formed from the debris from created by a massive collision between a large asteroid (about the size of Mars) and the early Earth.

Originally the Moon spun on its own axis much more quickly than it does today, as did the Earth. However, over time the Moon’s spin slowed down. This is because the gravitational pull of the Earth on the Moon distorted its shape, making it bulge in the centre and ultimately (it took an estimated 1,000 years) it slowed it down until the speed at which is spun on its axis matched the rate at which it orbited the Earth. This is why we only see one face of the Moon. If you still find that hard to understand test it out with two balls or check out this great video by Minute Earth.

Almost all moons in our solar system spin on their axis at the same speed as they orbit their planet.

Of course the gravitational forces between the Earth and the Moon are not one sided, the Moon also has a gravitational pull on the Earth and this causes some obvious effects here on Earth, like the tides in our oceans and seas.

Not that we know how it got there, let’s consider what would happen if it suddenly disappeared.

  1. Darker nights

    Although the night sky would still be lit by so many stars in our galaxy we would definitely notice it darker without the Moon. The full Moon on a cloudless night provides enough light for us to navigate by, in fact we can nearly read by its light. On these nights the Moon is about 1500 times brighter than Venus, the next brightest object in our night sky.

  2. Shorter days

    Without the stabilizing effect of the Moon, the Earth would begin to spin more quickly. It is estimated that a day on Earth would eventually only be about eight hours long, meaning there would be about three times more days (1095) in a year. However, this effect would happen very, very slowly. How long?

  3. Less extremes between high and low tides

    The gravitational forces exerted by the Moon causes tides to rise and fall in our seas and ocean, this is called lunar tides. Without the Moon we would see a big drop in the difference between high tide levels and low tide levels. There would still be some tidal difference (as the Sun exerts a gravitational force too – solar tides) but it would be a lot less, maybe as much as 40% less than what we have now.

  4. A more extreme climate

    As mentioned above, the Earth would spin more quickly on its axis without the Moon around to slow it down. The Earth is also tilted slightly on its axis as it spins. At the moment the Earth is at a tilt of 23.5 degrees on its axis. The Earth’s tilt can wobble slightly, but, due to the Moon, it never stays between 22 and 26 degrees. Without the stabilising forces of the Moon the Earth would wobble a lot more as it spins. This would lead to changes in our seasons. Sometimes it would tilt too far, resulting in extremes of temperatures and seasons. Sometimes there would be no tilt at all, meaning no seasons at all. Whatever way it goes, we would certainly find some extremes in our weather conditions if we had no Moon.

  5. No solar eclipse

    A solar eclipse happens when the Moon gets between the Sun and the Earth, casting a shadow over the Earth. There are different types of solar eclipses, but a complete solar eclipse is quite a spectacular show, the entire sun can be blocked briefly by a full moon, causing complete darkness from the correct viewpoint on Earth. Without a Moon, these spectacles (which can occur somewhere on earth every 18 months or so) would cease! Of course  lunar eclipses would no longer exist either; A lunar eclipse occurs when the Sun, Earth and Moon align with the Earth in the middle, casting a complete shadow on the Moon and preventing any of the Sun’s light from reflecting off it .

  6. No Werewolves!

    We are back to the werewolves. My kids put up a good argument that without a moon Were-people could not change into Werewolves, and they therefore wouldn’t exist. I know better than to argue with that one!

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If your questions expand beyond the Moon why not check out my Appliance of Science column in today’s Irish Examiner where I answer questions on the Universe and beyond.

Can water go uphill? A rainbow water experiment

Can water go uphill? A rainbow water experiment

nao

Can water go uphill? The answer is… yes it can! In some ways anyway; water can travel upwards by a process called capillary action.

Capillary action can be described as water climbing upwards due to weak forces created between the water molecules and the material the water moves up along, or through. In the experiment below the water travels up the paper towel, forming these forces with the paper towel as it creeps upwards.

For this experiment you will need…

  • six clear cups or bottles
  • six pieces of paper towel, folded length-ways into long strips
  • A jug of water
  • Food colouring… red, yellow and blue

What you do…

We arranged our six bottles in a circle (but you could do this in a straight line too, if you want to create the same colours as us, you will need seven bottles in a straight line, with one colour repeated… think about it 😉 )

Half fill every second bottle with water, leave the other bottles in between empty.

Add a few drops of food colouring to each bottle containing water, red in one, yellow in the next and blue in the next.

Now take a piece of the folded paper towel and place one end into the bottle containing red-coloured water, and the other end into the empty bottle beside it; make sure the paper towel sits into the coloured water.

Take another paper towel and place one end in the empty bottle (that is now connected to the red-coloured water bottle) and the other end into the bottle containing yellow-coloured water.

Repeat this all around the circle so that the paper towel ‘wick’ goes from the yellow-coloured water bottle to an empty bottle and another from that empty bottle to the blue-coloured water bottle; finally place a paper towel ‘wick’ from the blue-coloured water bottle to an empty bottle and another from that empty bottle to the red-coloured water bottle.

When all set up it will look like this…

walking-water-1

walking-water-2

Then all you have to do is wait! You should see the water starting to climb up the paper towel ‘wicks’ within a few minutes. Leave the experiment for a few hours or overnight to get the final result.

Results:

Eventually the water will travel up one side of the paper towel and down the other side, starting to fill the empty bottle. As water comes into the empty bottle from each side, the two colours of water will mix.

The red and yellow-coloured waters will mix in the bottle between them, creating orange-coloured water.

walking-water-4b

The yellow and blue-coloured waters will mix in the bottle between them, creating green-coloured water.

walking-water-3b

The blue and red-coloured waters will mix in the bottle between them, creating indigo-coloured water.

walking-water-5

You will notice that all the bottles have now got about the same amount of water in them. Once this happens no more water will transfer between bottles.

walking-water-7b

walking-water-6

What is happening?

As mentioned above, the water is able to climb up the paper towel due to these forces, called adhesive forces, that form between the water molecules and the paper towel.  This process is called capillary action.

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On the subject of water, if you ever wondered why our fingers wrinkle in the bath check out my recent Appliance of Science column in the Irish Examiner.