Wireless power for all your Christmas presents!!!!

1) Power from mains to antenna, which is made of copper
2) Antenna resonates at a frequency of 6.4MHz, emitting electromagnetic waves
3) 'Tails' of energy from antenna 'tunnel' up to 5m (16.4ft)
4) Electricity picked up by laptop's antenna, which must also be resonating at 6.4MHz. Energy used to re-charge device
5) Energy not transferred to laptop re-absorbed by source antenna. People/other objects not affected as not resonating at 6.4MHz

More details on this link: http://news.bbc.co.uk/1/hi/technology/6129460.stm

Now you know how one of these works!!!!!

Could Santa deliver gifts to all the world's children in one night?

Of course he can, with help from Nasa, Einstein and 360,000 reindeer. Scientists have been wrestling with the feasibility of Santa's job description since the 1850s. The latest thinking is that delivering one kilogram of presents to the world's 2.1 billion children (regardless of religious denomination) is entirely realistic, with a little lateral thinking.

Scientists at the American space agency, Nasa, reckon the man from Lapland relies on an antenna that picks up electromagnetic signals from children's brains to know what presents they want. Assuming an average of 2.5 children per house Mr Claus must make 842 million stops tonight to fill his orders.

By allowing a quarter of a mile between each stop, he must travel 218 million miles with about a thousandth of a second to squeeze down each chimney, unload a stocking, eat a mince pie, swig cooking sherry and get his sleigh airborne again. To achieve this he must travel at 1,280 miles per second. Travelling east to west, he can stretch Christmas Day to 31 hours.

To have enough presents, Santa's sleigh must carry 400,000 ton of gifts. With the average non-turbocharged reindeer capable of pulling only 150kg, Father Christmas would need 360,000 reindeer to heave his vehicle skyward.

The cavalcade would have a mass of about 500,000 tons which, at the required speed, would cause each reindeer to vaporise in a sonic boom flattening every tree and building within 30 miles. Father Christmas would have a mass of two million kilograms, causing him to combust when his reindeer come to their sudden halt. Piffle.

First, Einstein's theory of relativity dictates that the faster an object travels, the slower time appears to pass. So at the speed he is travelling, .0001 of a second allows Santa to perform his tasks at leisure pace. Second, as an expert in quantum physics, Mr Claus knows wormholes in the fabric of universe allow him to move instantly from one dimension and place to another. His sleigh is a time-machine powered by an unknown fuel which any economy on the world would have on its Christmas list.

Grow your own stalactite - yes, honestly it can be done, and it looks like an icicle, handy as a decoration for the coming festivities.

You will need:

Salt
Two small jars
Large paper clips
Wool or string
A small saucer.

What to do:

Stir plenty of salt into a large glass of very hot water. Keep stirring. If all the salt dissolves, add more. Allow to cool, then pour half into each jar.
Attach a paper clip to each end of a piece of wool - about 40 cm long.
Put one end of the wool in one of the bottles, and the other end of the wool in the other bottle. Make sure the ends of the wool are in the solution.
Now make sure that the bottom of the loop of wool between the bottles is hanging below the level of the salt solution in the bottles.
Place a saucer under the bottom of the loop of wool. Leave for a week.

What’s going on?

The salt solution travels along the wool by capillary action. This is a physical effect by which water can travel upwards as if to defy gravity! It is due to the interactions between the water molecules and the wool which contains tiny tubes and spaces for the solution to fill. Plants take advantage of capillary action to pull water from the soil into themselves.

As the salt solution travels along the wool it starts to drip off the lowest point of the loop of wool. The water evaporates and salt crystals are left behind. In time more and more salt solution drips down and the crystals of salt grow larger. Eventually it forms a stalactite.

Stalactites and stalagmites, collectively known as speleothems, form due to water seeping through rock. As the water moves through the rock, it dissolves small amounts of limestone or calcium carbonate. When the water drips from a cave ceiling, small amounts of this limestone are left behind, eventually leaving an icicle shaped stalactite. Limestone that reaches the cave floor "piles up" and forms stalagmites.

Frosted glass

Do you remember the days before central heating? Jack Frost painting pretty pictures on the windowpanes? No? Well lucky you! Anyway it is all due to the formation of crystals. Try it for yourself.

You will need:

glass jam jar
glass bottle or jar
Epsom salts (magnesium sulphate) available from chemist shops
water
paint brush

What to do:

Dissolve Epsom salts (magnesium sulphate) in a jam jar of hot water until no more will dissolve.
Brush a small amount of the liquid onto the bottle or jar.
Leave for 15 minutes or so and the liquid will quickly evaporate, leaving behind a patchy pattern of delicate crystals.
When it is dry, paint on another layer and continue until the glass or jar is covered with a film of beautiful needle shaped crystals.

What's going on?

Epsom salts is a common name for magnesium sulphate heptahydrate, MgSO4·7H2O, a water-soluble bitter-tasting compound that occurs as white or colourless needle-shaped crystals. It was first prepared from the waters of mineral springs at Epsom, England; it also occurs as the mineral epsomite. Epsom salts are used medicinally as a purgative; hence the phrase "through you like a dose of salts"!
The salt solution is called 'saturated' - it is holding as much salt as it possibly can. As some of the water slowly evaporates, the water that's left can't hold all the dissolved salt. The Epsom salts recrystallise and appear as an intricate pattern of needle shaped crystals on the glass surface.
Crystals are a 3-dimensional organised array of atoms or molecules. They grow in particular shapes depending on how each face of the crystal develops. Magnesium sulphate is orthorhombic in shape. In some cases other crystals start to form on top of the faces to give extraordinary patterns such as those seen in snowflakes.

Exploding Oatcakes - more energy than TNT!!!!!!!

Hard to believe? The facts are easy to find. From published data, we can find that TNT yields about 4.25 megajoules of energy per kilogram when detonated, fairly typical for a high explosive.

Next, off to the kitchen cupboard. The oatcake packet tells me that oatcakes yield 18 megajoules per kilogram. This is more than 4 times as much energy as in the TNT.

So why are oatcakes so much less spectacular than TNT? It's because explosions are not so much about releasing a lot of energy, they're about releasing it very quickly. TNT certainly does that – an oatcake-sized amount of TNT releases its energy in a fraction of a microsecond. This creates huge gas pressures, and hence an explosion. An oatcake, on the other hand, takes minutes to burn.

Now there's one thing I haven't mentioned. Explosives include everything needed for the reactions that make them go bang, but an oatcake needs a source of oxygen. We really ought to include the mass of the oxygen along with the mass of the oatcake. The packet says that oatcakes contain a lot of carbohydrate, with about a third as much fat. Carbohydrate needs about its own mass of oxygen to burn, and fat needs about 3-4 times as much. It works out that a burning oatcake consumes about 1.5 times its own mass in oxygen. So the 18 megajoules that we get from a kilogram of oatcakes actually comes from about 2.5 kilograms of material. Even so, it still beats TNT.

There's another important factor: whereas the chemicals in explosives are already exactly in position and ready for action, the oxygen that an oatcake needs is not inside the oatcake. The rate at which the oatcake burns depends on how fast we can supply oxygen. If we could somehow incorporate enough oxygen right inside the oatcake, it might indeed go off with a bang. Would that make it a cracker?

Can a pressure washer peel off your skin - watch and find out!

Ever wondered how a catherine wheel firework works?

Make amazing sounds with simple objects.............

Cloud in a jar

They say every cloud has a silver lining. Maybe it’s time to find out.

Adult supervision required

You will need:

Matches
Glass jar
Small bag of ice
Hot water
Black paper (optional)
Sticky tape to secure the black paper around the back of the jar (optional)

What to do:

Cut a small piece of black paper and secure it around the back of the jar with sticky tape. This helps us “see” the cloud better.
Pour hot water into the jar until is 1⁄4 full.
Light a match, place it over the opening of the jar and blow it out. (this must be done by an adult).
Wait a second or two then drop the match into the water inside the jar.
Quickly place the bag of ice on top of the jar covering the opening. Make sure the ice does not go down into the jar but just across the top.
Watch as the cloud begins to form!
Lift the ice and watch the cloud come out. COOL! Now’s your chance to grab it and check whether it has a silver lining. Good luck with that!

What’s going on?

The warm water heats the layer of air that it touches. Some of the water evaporates into the air forming water vapour. The warm air containing water vapour rises, and then cools, as it comes in contact with the air cooled by the ice. When the water molecules cool, they slow down and stick together more readily. The particles of smoke act as nuclei for “bunches” of water molecules to collect on. This process is called condensation.

Clouds in the real world form in a similar way to the one created in the jam jar. As the atmosphere (air) cools, water vapour suspended in the atmosphere condenses into water droplets around condensation nuclei (tiny particles of dust, ash, pollutants, and even sea salt).

In this experiment the ice is used to cool the air, however, in the real world the main cause for cooling air is to force it to rise. As air rises it expands - because the pressure decreases through the atmosphere - and therefore cools. Eventually it may become saturated and the water vapour then condenses into tiny water droplets, similar in size to those found in fog, and forms cloud. If the temperature reaches below about -20 °C, many of the cloud droplets will have frozen so that the cloud is mainly composed of ice crystals.

Why does a champagne bottle have a concave bottom?

IB Physics trip to Dreamworld

No comments please! The year 12 biologists are out on their field trip at the moment (no wonder it is so quiet) and you may be wondering if the physicists go somewhere. Well, a couple of weekends back they went measuring, recording, calculating and experimenting (including measuring the g-force of each ride with a home made g-force device) at dreamworld. Mr Roff asked for them to send some interesting photos and this is what he they sent him. Who said physics was boring?