Cette photo a été prise dans une classe de physique, toutes lumières éteintes, avec un appareil numérique. Elle a été prise à une distance d’un mètre de l’écran de projection, sans faire de zoom et sans flash. Un laser hélium-néon bien étanchéisé a été utilisé. Un écran de projection a été placé à environ un mètre de la source du rayon laser. Un tube de plastique cylindrique d’un diamètre de 4 cm a été placé à angle devant le laser. Le rayon laser est visible au-dessus du cylindre de plastique. L’angle d’incidence étant plus grand que l’angle critique, il y a réflexion totale interne, ce qui enferme le rayon laser dans le cylindre. Le même processus se répète jusqu’à ce que le rayon laser atteigne l’extrémité du cylindre. On peut voir une spirale sur le cylindre en raison de la réflexion totale interne. Cela est aussi projeté sur l’écran de projection. Si des taches claires y apparaissent, c’est qu’un peu de lumière filtre du tube de plastique. Le rayon est réfracté en passant à travers le tube de plastique de sorte qu’il semble différent sur l’écran de projection.

Talha Qureshi et Sarvatil Bhatt
Emery Collegiate Institute, North York, Ontario
(1er prix, Classe, École secondaire ou cégep)

This picture shows a thin film of soap directed vertically from the ground using a wire loop. A Canon digital camera, with power shot SD 400, and 5.0 mega pixels was used to take this image. The pattern appearing in the photo is produced through optical interference when a thin film reflects light. When the light rays strike the surface of the thin film, some of the light is reflected, while some is refracted. On the bottom surface, a similar process is occurring. As a result, two rays are reflected to the eye of the observer: the first ray from the top surface and the second ray from the lower surface. The pattern seen in the photo also results from the constructive and destructive interference pattern. Also, the effect of gravity (on a vertical soap film) causes the film to portray the patterns illustrated in the photo: thick at the bottom and thin at the top. The interference pattern was created using sunlight at sunset time, which is why an image of the sunset is visible in the photo.

Dhanisha Patel
Emergy Collegiate Institute, North York, Ontario
First Prize ( High School Individual Category )

This is an image of a physics tow, which is both diverted and inverted on concave and convex mirrors, respectively. A Canon camera, with power shot of SD 400, and 5.0 mega pixels was used to take this image. The main concept portrayed in this image is that it explains the images produced by both concave and convex lenses. When considering the concave lens (the vertical lens in the image) the rays go through the lens and diverge, meaning spread out, which makes the image bigger than the actual object. As for convex lens (the lens under the actual object), when rays pass through the lens, the rays become converged; meaning become focused, which makes the image smaller than its actual size. From this, we know that a concave mirror produces an image right side up and larger than the actual size, whereas a convex mirror produces an image right side up and smaller than the actual size. This concept is fully illustrated in the corresponding photo, where it becomes difficult to distinguish between the actual toy and the produced image by the mirrors, thereby creating a colourful maze analogy!

Krupal Kavathia
Emergy Collegiate Institute, North York, Ontario
Second Prize ( High School Individual Category )

This image was captured around sunset in early June 2007. After a day's exposure to the sun, the landmass was much warmer than the air in the atmosphere, allowing for the largest difference in temperature between the air and the ground. The soil's ability to hold heat and the paved roads contribute to the black body emitter which in turn serves as the buoyancy force required to displace the clouds overhead. What this picture illustrates is the atmosphere's stratified response to lateral heat from the ground and the restoring force of gravity from above. The path of such phenomena is overshadowed by the parcels in clouds which are set in motion by the wind. As the air parcels expand and rise, the wind continues to move the clouds laterally, resulting in the bird like shape. The structures of these clouds are well retained as a wind speed of 9 Km/h, and cooler atmosphere allowed for a slower but inevitable disperse time. Such transition steps have been captured by the clouds in this image.

Shahin Barbod
Toronto, Ontario
2nd Prize ( Open Category )

Voici une photographie d’une gerbe qui s’est formée à la suite de la chute d’une goutte d’eau dans un réservoir d’eau. Si une goutte tombe d’une certaine hauteur dans un contenant d’eau calme, elle déplace l’eau de la surface et s’enfonce à une certaine profondeur, formant des vagues concentriques. Si la vitesse de choc est suffisante, la goutte rebondit alors et ressort du réservoir d’eau, créant la gouttelette d’eau dormante inversée qui apparaît sur la photo. La goutte d’eau dormante est le résultat de la troisième loi de Newton (action/réaction) et des propriétés de cohésion et de tension de l’eau. La hauteur initiale de laquelle la goutte est lâchée détermine la hauteur du rebond ultérieur.

Irina Gorbounova,
École secondaire catholique St. Elizabeth, Thornhill, Ontario
(1er prix, Individuel, École secondaire ou cégep)

Dans cette photo, une bouteille d’eau remplie de bulles est tenue devant le soleil. La photo illustre le phénomène de la dispersion de la lumière, visible près des parois de la bouteille où les petites bulles font office de prismes minuscules réfractant la lumière et la décomposant en diverses couleurs. Cependant, le phénomène ne se produit pas vers le centre de la bouteille, car la lumière du soleil est trop intense pour être photographiée. Tout comme les gouttelettes de pluie, ces bulles minuscules réfractent et dispersent la lumière; celle-ci se propage dans l’air à partir des bulles et est réfractée en touchant l’eau, ce qui amène les différentes fréquences de couleurs à se propager plus ou moins vite; certaines couleurs étant réfractées plus que d’autres, différentes couleurs sont visibles.

Mansoor Saqih et Nauman Sharif,
Emery Collegiate Institute, North York, Ontario
(3e prix, Individuel, École secondaire ou cégep)

Multiply scattered elastic and acoustic waves can reveal a wealth of useful information on the dynamics of complex media. Because the waves sample the medium many times (due to multiple scattering), they are very sensitive to small changes in the physical system. Here we see a mug of beer with Mount Merapi in the background. In the beer mug, an ultrasonic transducer produces a short acoustic pulse, which is scattered many times by the walls of the mug and the beer bubbles. The scattered signal is picked up by a miniature hydrophone, and by observing how the scattered wave changes with time, we can learn about the concentration and speed of the bubbles. Geological changes can be monitored in a similar way. At Mount Merapi, an active volcano on the island of Java in Indonesia, seismic waves are excited by an air gun and detected many kilometers away, after being multiply scattered by heterogeneities in the Earth. These examples illustrate the diversity of applications using multiply scattered waves that are being developed to monitor temporal changes with exquisite sensitivity over a huge range of length and time scales.

William Kurt Hildebrand and John H. Page
University of Manitoba, Winnipeg, Manitoba
Second Prize ( Open Category )

The force of gravity acts towards the centre of the Earth, so how can these icicles grow almost horizontally? The answer requires the concept of the "centre of gravity" of an object, the point at which the object can balance on your finger tip. The icicles in the photograph initially grew vertically, formed as the snow on the roof slowly melted and refroze at the lowest point. However, the snow also slowly slid down the roof, to extend beyond the roof edge. To do this, the snow had to be a semi-fluid, so it could flow slowly but remain fairly rigid. As the leading edge of the snow moved further from the roof, the only way the centre of gravity could remain under the point of support was for the snow to curve backwards, resulting in the icicles tipping to become almost horizontal.

Alan Slavin
Trent University, Peterborough, Ontario
Third Prize ( Open Category )

The photograph shows the trajectories that an electron beam follows when it moves through a uniform magnetic field. The tube contains a small amount of mercury gas that is used to make the electron beam visible. Electrons are accelerated by a potential difference applied between two plates and they collide with the gas atoms emitting a characteristic green light. When the velocity of the charged particles is perpendicular to the uniform magnetic field, they experience a magnetic force that makes them move in a circular path (left side). However, if the direction of the velocity of the beam is at some arbitrary angle, the charged particles describe a helix (right side).

Sergio Andrés Joya
Vanier College, Montreal, Quebec
Third Prize ( High School Individual Category )

Un générateur de Van de Graaff a aidé à produire l’étincelle sur cette photographie. Il fonctionne en créant un surplus d’électrons sur la sphère métallique. Les électrons cherchent toujours la voie de moindre résistance vers la terre. Dans ce cas-ci, notre sujet de gauche est en contact avec le générateur de Van de Graaff, mais il est debout sur une plateforme de bois, pointant le doigt vers l’autre sujet sur la droite. Cette plateforme de bois étant un isolant, la voie de moindre résistance vers la terre, pour les électrons, n’est pas le corps de notre premier sujet, mais celui de notre deuxième. Pour boucler le circuit, les électrons ont utilisé l’air entre les deux doigts, une fois ceux-ci à la bonne distance. Cela crée un courant qui a mené à la terre. L’étincelle de lumière blanche, visible sur la photographie, est le courant qui se décharge entre les doigts et va enfin jusqu’au sol.

Alyssa Terminesi,
École secondaire catholique St. Elizabeth, Thornhill, Ontario
(2e prix, Individuel, École secondaire ou cégep)

This image was taken during the lab component of an Undergraduate course in optics. My lab partner and I are measuring the attenuation, or loss of light to absorption and leakage, in a half-kilometer spool of commercial optical fiber used for communications. A Helium-Neon laser, focused down to a point with a 10x objective lens borrowed from a student microscope, provides illumination. A photometer measures how much light reaches the other end of the fiber. The method used to 'fill' the fiber with light is very important; poor alignment can result in excessive loss of light. Here, the laser is deliberately misaligned, causing the whole cable to glow bright red.

Alasdair Dunlap-Smith
Mount Allison University, Sackville, New Brunswick
First Prize ( Open Category )

This picture depicts a chord being plucked on a guitar, and ultimately demonstrating vibration and in the case of a guitar, how it creates sound. The source of the sound emitted from a guitar comes from the vibration of the strings when they are plucked or strummed, as caught in motion by the photo. As important as they are, the strings themselves create very little noise and disturbance in the air. The body of the guitar acts as an amplifier, due to acoustic resonance, and in a sense elongating the vibrations caused by the strings further creating the sounds you hear. The mass and tension of the strings greatly affect its vibration. The tighter the string is, the higher the frequency becomes and the higher the pitch and vice versa. The body of the guitar -- the size and amount of air inside it -- also affects the sound being produced. When a chord is hit, it causes the air next to it to compress. This compression causes a chair reaction outwards allowing the next layer of air to compress as well. This continuous chain reaction, momentously leading to a disturbance in the air, continues to develop and spread out as a traveling sound wave which we can hear. The camera is a Finepix Z10z, 7.2 MP. This photograph was taken on Night mode because it has slower shutter speed in order to capture the vibration efficiently.

Raymond Ngo and Saadia Malik
Emergy Collegiate Institute, North York, Ontario
First Prize ( High School Class Category )

Voici une photographie d’un bâton de bois qui conduit l’électricité. Pour produire une étincelle à partir du transformateur élévateur de tension, il faut : i) réduire la distance entre les deux électrodes, ii) augmenter le voltage, ou iii) laisser la tension croître au point que la différence de potentiel devienne si grande que les électrons soient forcés d’utiliser l’air comme voie menant à l’autre électrode.  Les électrons cherchent toujours la voie la plus facile pour boucler un circuit ou atteindre le sol. Dans ce cas-ci, en dépit de l’isolant qui les bloque, les électrons trouvent quand même une voie d’une électrode à l’autre. Des électrons sont arrachés aux atomes du bâton en bois pour créer un courant et boucler le circuit, conduisant ainsi l’électricité.  La foudre frappant un poteau de téléphone ou un arbre serait un autre exemple d’électrons cherchant la voie de moindre résistance vers la terre. En raison d’une grande accumulation d’énergie, la foudre frappe le poteau de téléphone en bois ou l’arbre, même à travers un isolateur, afin de parvenir au sol. Les électrons sont arrachés aux orbites des atomes du poteau de téléphone ou de l’arbre et créent un courant qui atteint le sol.

Alyssa Terminesi,
École secondaire catholique St. Elizabeth, Thornhill, Ontario
(2e prix, Classe, École secondaire ou cégep)