## Fun Friday – Static Electricity

### What is Static Electricity?

Static electricity is a charge that builds up when two things are rubbed together. Matching charges of static electricity push each other away (repel) while opposite charges attract each other.

Everything is made up of atoms.  An atom is the smallest piece you can break an object down to while still maintaining it’s properties.

 photo credit: ProLithic 3D via photopin cc

Atoms are made up of protons, neutrons and electrons.  Protons have a positive (+) charge, neutrons have no charge (neutral) and electrons have a negative () charge.

At the centre of each atom is a nucleus, this is where the protons and neutrons are found.

The electrons are found to the edge of the atom, they are constantly moving in a circular motion around the nucleus.

When two objects are rubbed together electrons pass from one to the other, making one more positively charged and the other more negatively charged.  This charge is called static electricity.

### How does lightning work?

 photo credit: Brujo+ via photopin cc

Lightning is caused by a build up of static electricity in clouds.  As the charge in the cloud grows, the base of the cloud builds up a strong negative charge.  This negative charge creates a build up of positive charge in the ground.

If the attraction between the cloud and the ground (or between two clouds) becomes strong enough, a spark of lightning will jump between the two.  This lightning is a giant spark of moving electrons travelling between the cloud and the ground.

Did you know… that the heat of a lightning bolt is hotter than the surface of the sun?

Some things give up or take on electrons more easily than others.

Objects can be ranked according to how easily they give up or take on electrons and this ranking is called the triboelectric series.  Things listed at the top of the triboelectric series give up electrons more easily than those ranked below.

### Experiment to try at home

 photo credit: Kevin Baird via photopin cc

### 1. Hair raising fun!

You will need… a balloon and a good head of hair!

What to do… blow up the balloon and tie it tight.  Rub the balloon all around your hair (this is called charging the balloon); Now move the balloon slowly away from your head and watch your hair stand on end!

So what is happening?… When the balloon is rubbed on your hair electrons are passed from your hair to the balloon.  This gives the balloon a negative charge and your hair a positive charge.  As opposites attract, your hair is attracted to the balloon and sticks to it while you pull it away.

### 2. Attract a can!

You will need… a balloon, a good head of hair and an empty aluminium can!

What to do… charge the balloon on your hair as before.  Lay the empty aluminium can on it’s side on a table.  Then bring the charged balloon close to the can, but do not let it touch it.  Slowly draw the balloon away from the can and watch the can follow.

So what is happening?… The aluminium can becomes attracted to the negatively charged balloon as the area around it becomes positively charged.

### 3. Bending water!

You will need… a balloon, a good head of hair and a running tap!

What to do… Turn on a tap to a small, steady stream of water and leave it running.  Charge the balloon on your hair as before.  Bring the charged balloon slowly towards the stream of water and you should see the stream of water slowly bend towards the balloon! (If the experiment does not work for you just reduce the flow of water).

So what is happening?… Just as with the aluminium can, the stream of water becomes attracted to the negatively charged balloon as the area around it becomes positively charged.

I hope you have some hair raising fun with these experiments :0)  If you have any questions or queries, or would like me to cover a particular subject in the Fun Friday blog, please just leave me a comment below!

I am going to take a little blogging break for a couple of weeks but will return in August for plenty more fun, facts and experiments to share.

## Blue Sea Slug

May 6th – 12th 2013

Well did you guess what this week’s creature was?  For those of you who had it just on the tips of your tongue … let me put you out of your misery… its a Blue Sea Slug, also known as a sea swallow or a sea dragon!

Blue sea slugs float on their backs on the top of the sea, so the beautiful blue colours we see are actually the underside (foot) of the creature.  Their backs, submerged in the water, are actually a silvery-grey colour.  They are able to float due to a large sac in their stomach which they fill with air.It’s official name is a Glaucus atlanticus and it is a nudibranch (a shell less* mollusck). These little creatures usually only reach about three to four cm in size but don’t let that fool you…. they have a mean sting!  The blue sea slug preys on larger toxic sea dwellers such as the Portuguese Man O’ War (Physalia physalis).  It is immune to the stinging cells (nematocytes) within these creatures and is also capable of storing these deadly toxins within its own body and using them for its own defense.   The more venom it accumulates the deadlier its sting!

*Nudibranches may have shells during early stages of development but are shell less when fully mature).

## Sticky toes

We are amassing quite a collection of geckos around our house these days.  Not the organic variety of course, although that would really please the kids!  No, our collection consists of ornaments, wall hangings, trinkets and even jewellery.  It all started ten years ago when on honeymoon in Barcelona … the little guys were everywhere and we were drawn to them with fascination – especially their ability to scale any surfaces they encountered (even glass).  So the collection started from there, anytime we come across a quirky gecko decoration or ornament we like, we purchase and add it to the collection!

Ten years on and our fascination has grown along with our collection.  I was delighted to show my children a recent photo from National Geographic of a gecko.  Of course that lead to the children asking questions, that lead to questions, that led to the ultimate… “How do they walk up walls?” After answering their questions I decided this might be a good topic to start my 2013 blog with.  So…how do these amazing little creatures manage their “spiderman-like” feats? It truly is a marvel of nature but before I delve into that, I want to tell you a few other quirky facts about these lovely little creatures.

Geckos are a type of lizard.  They are found on all continents except Antartica.  They come in many shapes and sizes and are in fact the most species rich order among lizards.  They are also among the most colourful lizards in the world.

Most species of geckos can actually sever part of their tail, usually to escape the hold of a predatory or threat.  The released tail segment can keep wriggling as a distraction while the gecko escapes.  PRETTY COOL DON’T YOU THINK?  This process of severing the tail is called caudal autotomy!

Another very interesting fact about geckos is that nearly all species of geckos have no eye lids and can therefore not blink. Instead, they use their long tongues to clean any dust from their eyes.

Already you can begin to see how fascinating these creatures are, and that is before we have even looked at their ability to apparently defy gravity! DID YOU KNOW THAT A GECKO CAN SUPPORT ITS ENTIRE BODY WEIGHT ON ONE TOE?

So here is the science bit behind HOW THEY DO IT…the toes of a gecko are covered in hundreds of small ridges called lamellae.  Each ridge is covered in millions of hairs called setae.  Setae are much thinner that human hair (up to 30 times thinner).  Each seta then splits at the top into tiny strands called spatulae – there can be up to 1000 spatulae on one seta (if you think you have problems with split ends, pity the poor gecko!).  So you can begin to imagine how tiny these spatulae are, in fact, they are so tiny that they can bond with the molecules of the surface they are touching.  This bonding is referred to as van der Waals interaction!   The great thing about it is that it is what is called dry adhesion – it doesn’t require any sticky compounds or leave any messy residue.

This gives us an idea of how the gecko sticks to the surface, but HOW DOES IT UNSTICK?  The adhesion (sticking) process is said to be one-directional…imagine sticking a piece of sticky tape to a surface and then taking hold of one edge and peeling it back to remove it… the gecko does something similar.  Geckos toes bend in the opposite direction to humans so they can “peel” their toes off the surface from the tip backwards.  Add to this the fact that geckos have rotating ankles and you start to understand how they can move in any direction.

As you can imagine this ability has captured the interest of Scientist for a long time.  Imagine if we could copy this adhesion from the gecko… what could we do with the technology??? Robots that can scale any surface would be great in extreme or rescue situations, right?  Or how about a suit we could wear to allow us to climb like a gecko? Did you know that geckos can climb in a vacuum? So now we can start thinking about using this technology in space!  Or how about using the technology in bandages – inspired by the observation that geckos can climb in wet conditions… a bandage that stays on when wet.

Maybe YOU can think of another novel way to use gecko technology?  If you have any ideas I’d love to hear them!