The Science of Curling

It's played in teams of four people, and teams take it in turns to slide eight tones across the ice towards a target, trying to get as close to the centre - called the tee - as possible. The team with the nearest stone to the tee scores a point, and for every other stone nearer the tee than their opponents', they score another point. What makes curling so curious to watch though are the two team members who use brushes to try to control the slide of the stone. Curling is a fascinating interplay of force, friction and momentum, based on the fact that it's easy to slide things on ice. Just like a toboggan or ice skate, the curling rock slides because the pressure it exerts melts the ice beneath it, creating a thin film of water that lubricates its passage. The player's goal is to balance the energy he imparts to the rock with the friction of the rock on the ice, so that friction will win just when the rock is where he wants it to stop. Curling would just be called "sliding," however, if not for the fact that the rocks are made to curl, or curve, as they move down the ice. The stone is a round piece of polished granite, concave on top and bottom. The direction in which the stone curls is very important. A stone rotating in an anticlockwise direction will curl to the left. This is because as the stone travels it tips forward. The pressure of the stone on the ice is greater at the front and causes more melting (momentarily) than the back. Consequently there is a layer of water between the stone and the ice and so less friction at the front of the stone than at the back. And the frantic sweeping? Sweeping the ice just in front of a rock with a broom makes it travel faster and curl less. Sweeping melts the ice a little bit, decreasing friction, and removes any debris that might slow the rock. Read more about science of curling.... or click the picture to see some flash animations on curling.

International Day and the Winter Olympics

If there were a gold medal for the bravest people at the Winter Olympics the competitors in the luge and skeleton would surely win. They use the same courses as the bobsleigh event, but rather than encase themselves inside a mini-vehicle they instead prefer a flimsy-looking piece of plastic that looks like a tea-tray. The main difference between the two disciplines seems to be the direction the athletes shoot down the track in - with lugers going feet first on their back and skeleton sliders going headfirst on their front. And the tea-trays - really called pods - have no brakes. The athlete steers the skeleton by gently transferring weight to the left or right. They take as direct a line as possible and avoid contact with the walls. Wind resistance is reduced by keeping elbows in and shoulders in contact with the sled. After the finish, the feet are dragged along the ice to bring the skeleton to a standstill. Britain (there is the connection with International Day!) has won its first Olympic medal after Shelley Rudman raced into second place to claim the silver in the women's Olympic skeleton. Click here to find out more.......

It's never too late to send flowers

Click on the flowers to find out what this nice flash site is all about. OK it's not a science web site but it's still worth a visit. Go on, send some flowers - it's never too late.

This Week in the Patana Science Department

OK, not really this week but last. Hope the half-term holidays have been good to you. Last week the year 8's were using disclosing tablets to stain areas of their teeth pink where plaque could be found. Apart from great fun walking around the lab and looking at everybody's red mouths we also learnt where to concentrate our brushing in the future. Your parents can buy these tablets from local chemists - please read the instructions carefully before using them.

Make your own pet cloud

You will need:

A large glass storage jar. 'Kilner' jars are good - they're the type with the big levered glass lid and a rubber sealing grommet. It's easiest to do the demonstration if you remove the lid completely, but it's not essential.
A rubber glove. Yes, you read that correctly.
A box of matches. Remember all the things everyone always says about playing with matches; be careful, and make sure there's someone else around who's more sensible than you are. That usually - but not always - means 'an adult.'
A cup of water.

What you do:

Tip the water into the jar and swirl it around a bit. Now light a match, hold it over the neck of the bottle while it flares and settles down, then blow it out again. Let some of the smoke fall into the jar, then drop the match in so it's safely quenched in the water.
Now comes the harder part: dangle the rubber glove into the jar, and stretch the cuff over the neck so it seals. This can be a bit fiddly, but you need the glove to be good and tight over the jar.
The final part is simple enough, but very hard work: hold the jar down with one hand, and with the other grab the inside of the glove. Pull the glove sharply out of the jar - you'll have to yank really hard. Don't slip and drop the jar on your foot, it'll hurt.
With a little luck, you'll see a cloud form in the jar. Wooo! When you let go of the glove, your pet cloud will evaporate back into water vapour - but it'll return if you pull the glove again.

What's going on?

Firstly, it's a genuine cloud in there. No, really. You might see it more clearly if you light the jar from one side with a desk lamp, and place some dark card behind it, but I have had this work quite clearly in plain daylight.

When you pull the glove, you reduce the pressure of the air inside the jar. That reduces the amount of water vapour (gas) that can be carried in the air; the water vapour then condenses into droplets of liquid. It'll tend to do this on the sides of the jar or the water surface at the bottom, but if there are a few small particles floating around - like smoke - it'll tend to form droplets on those instead.

That floating mass of tiny water droplets is... a cloud. Clouds form where the air temperature or pressure is just a little lower than is needed to keep the water as a gas. Which, in this case, is inside your jar.

Look after your pet cloud, and let me know if you manage to teach it any tricks. Other than hide-and-seek, of course.

About 100 billion solar neutrinos pass through your thumbnail every second.

The story of how many neutrinos the sun produces and how many reach the Earth is one of dogged persistence, the patience of Job, and a tight-knit collaboration between two researchers who steadfastly believed in their findings. In this interview with astrophysicist John Bahcall, who died in August 2005 at age 70, hear about the career-long quest that he and Nobel Prize-winning chemist Raymond Davis Jr. launched in the early 1960s and finally completed in 2001. When results announced that year proved them right, Bahcall, when asked how he felt, responded, "I feel like dancing I'm so happy." Read more......

This is not a Hoax

A photo of a one-eyed kitten named Cy drew more than a little skepticism when it turned up on various Web sites, but medical authorities have a name for the bizarre condition.

“Holoprosencephaly” causes facial deformities, according to the National Institute for Neurological Disorders and Stroke, part of the National Institutes of Health. In the worst cases, a single eye is located where the nose should be, according to the institute's Web site.

Traci Allen says the kitten she named Cy, short for Cyclops, was born the night of Dec. 28 with the single eye and no nose.

“You don't expect to see something like that,” the 35-year-old Allen said by telephone from her home in Redmond in central Oregon.

Allen said she stayed up all night with the deformed kitten on her recliner, feeding Cy a liquid formula through a syringe. She says she cared for the kitten the next day as well, until it died that evening.

Allen had taken digital pictures that she provided to The Associated Press. Some bloggers have questioned the authenticity of the photo distributed on Jan. 6th.

AP regional photo editor Tom Stathis said he took extensive steps to confirm the one-eyed cat was not a hoax. Stathis had Allen ship him the memory card that was in her camera. On the card were a number of pictures _ including holiday snapshots, and four pictures of a one-eyed kitten. The kitten pictures showed the animal from different perspectives.

Fabricating those images in sequence and in the camera's original picture format, from the varying perspectives, would have been virtually impossible, Stathis said.

Meanwhile, Cy the one-eyed cat may be dead, but it has not left the building.

Allen said she's keeping the cat's corpse in her freezer for now, in case scientists would like it for research.

She said one thing's for certain: “I'm not going to put it on eBay.”

Sex I.D.

Some researchers say that men can have 'women's brains' and that women can think more like men. Find out more about 'brain sex' differences by taking the Sex ID test, a series of visual challenges and questions used by psychologists.

• Get a brain sex profile and find out if you think like a man or a woman.
• See if you can gaze into someone's eyes and know what they're thinking.
• Find out why scientists are interested in the length of your fingers.
• See how your results relate to theories about brain sex.
  
  
  

Making the impossible possible!

Many physicists admire the precise manner in which toast contrives to land butter-side down when knocked off a table. The true connoisseur of domestic dynamics, however, will point to the humble wine-bottle cork as a bringer of even greater delight and fascination. To join the aficionados in their investigations, you will need: a cork. (Not one of those new-fangled plastic faux 'corks'; only a traditional, flat-ended cork will do. None of your fancy flared champagne corks, either.)

The Challenge

Drop the cork onto a table, lab bench, or other hard, flat surface, such that it lands standing upright rather than rolling around on its side.

Go on, try it. Not so easy, huh?


What's Going On?

As you will have discovered through empirical observation (i.e. you tried it, and it didn't work), the cork will bounce, tumble, and invariably settle on its side. Attempts to circumvent this behaviour by dropping the cork onto its flat end will only succeed for drops of a few miserable and unimpressive millimetres.

The knack is this: drop the cork on its side, from a height of about one-and-a-half times its own length.

Only very rarely will the cork land absolutely flat-on along its length. We'll call that situation by its technical name - a failure. Much more likely is that one end will strike the table first, so as the cork bounces, it'll start to rotate.

Judge the drop height right, and the amount of rotation will be just enough to bring the cork upright before it strikes the table a second time. The cork will rattle around before coming to settle upright. It's all rather satisfying when it you do it right.

Too high a drop will induce enough rotational momentum to spin the cork through far more than 90 degrees, at which point all bets are off. Too low a drop and you'll feel like an idiot as the cork pretty much just thuds to the table. But the range of heights over which the trick works is rather large (which is interesting in itself), and with a little practice it's possible to succeed about two times out of three.

Try it and see - all those around you will want to have a go when you succeed - just don't tell them how!

Make it Hover!

Patana's first hovercraft, expertly piloted by Roy.
WATCH THE MOVIE