Science movies

This website has all kinds of science movies from video on using the micrometer and all sorts of measuring instruments to videos on magnets and forces. Have fun surfing and learning using videos. Change your mindset!


http://www.neok12.com/

Thomas Young's experiment

Wave theory of light
In Young's own judgment, of his many achievements the most important was to establish the wave theory of light.

To do so, he had to overcome the century-old view, expressed in the venerable Isaac Newton's "Optics", that light is a particle. Nevertheless, in the early 1800s Young put forth a number of theoretical reasons supporting the wave theory of light, and he developed two enduring demonstrations to support this viewpoint. With the ripple tank he demonstrated the idea of interference in the context of water waves. With the two-slit, or double-slit experiment, he demonstrated interference in the context of light as a wave. He used reflection off thin films of soap and oil.

The picture ( which was an animation before I uploaded it ) shows a double slit source in front. If the particle theory alone was correct, what would be seen would be only two bright light lines on the screen. But what is seen actually are many bright( and dark) fringes which meant the 2 light sources had been diffracted and then experienced interference. which meant light was also a wave and not just a particle.

An earlier posting on my blog about the giant soap bubble showed colourful fringes in the soap bubbles which were a result of interference from two sources of light, one source from the upper skin of the bubble and the 2nd source - one reflected off the lower thin skin of the soap bubble

Never be afraid to think differently from the venerable authorithies eg Newton! You could prove them wrong. And thinking differently is innovation!

Dispute of two camps

In the early eighteenth century, the argument about the nature of light had turned the scientific community into divided camps that fought vigorously over the validity of their favorite theories.

One group of scientists, who subscribed to the wave theory, centered their arguments on the discoveries of Dutchman Christiaan Huygens. The opposing camp cited Sir Isaac Newton's prism experiments as proof that light traveled as a shower of particles, each proceeding in a straight line until it was refracted, absorbed, reflected, diffracted or disturbed in some other manner.

The above paragraph is taken from molecular expressions micro.magnet.fsu.edu/primer/lightandcolor/particleorwave...

Use some of the info and pics on my previous blogs on light and waves to help you decide. Who do you think is correct? Which camp are you on?

soap bubbles

What connections does soap bubbles have with Physics? Any wise guys out there?

The picture shows a giant soap bubble with happy children chasing after it at a beach.

I remember taking my three children when they were young to the National Science Centre back then near Lake Gardens to play with soap bubbles by dipping sticks with certain shapes into special soap solution and our delight as bubbles of various sizes and shapes emerged and mesmerized us with their dance before they burst.

Catch the video Giant Stinson Beach Bubbles (Canon 550D) on Youtube and be enthralled by the delight of the children at the beach.

Don't forget to think about the connection in Physics with these giant soap bubbles.

Bicheno, Tasmania 11th Sept 2002

I shall forever label Tasmania - the land of rainbows. We saw rainbows for five consecutive days!

Here at Bicheno, we saw end to end double rainbows appear, dissapear and then re-appear at least three times. in the space of one hour. Wow!

From the physics point of view, can you tell me 3 differences between the primary rainbow at the bottom and the secondary rainbow at the top?

Bicheno is also good for watching the wild fairy penguins for free unlike in Philip Island, where you have pay to enter the Penguin Parade place.

Cradle Mountain, Tasmania, 9 Sept 2002

I spy, I spy something down there Do you see what I see?

When I caught a fleeting glimpse of what I suspected - I was not too sure if it was true cos' my techo brain said otherwise.

But as we descended from the mountain to cross the bridge (I think this should be the Ford River) what I suspected was actually true - a beautiful rainbow over the river. Do you see it?

This rainbow was kinda unusual; it is very low and also the time was about mid noon. That's whyI didn't quite trust my eyes when I first saw it cos' my technical physics brain told me the objective data - that usually rainbows are formed during early morning or evening and in high places - not low places.

This rainbow was formed by the spray of the river water. That's why it could be so low since it didn't depend on raindrops - which was also why it could be formed even at about mid noon.

I snapped this picture in excitement. I was absolutely delighted when the rainbow showed clearly in the picture! Each time I look at this picture, it reminds me - it is wiser to trust my eyes , my heart and my gut feelings and not my techo brain. And it also reminds me that God can esaily re-arrange the time ( from evening to noon) and position ( high place to low place) as He wish and I was simply privileged to catch Him being sovereign!

Rainbows on shirts

I always had a penchant for rainbows. And when rainbows are that close to us - on the shirt (and near the heart) of my students in Seksyen 5- even nicer!

This rainbow spectrum was part of the Hodson Light Box Kit experiments where we conducted light experiments on thick and thin convex and concave lenses, plane and curved mirrors and lastly prisms.

The spectrum is formed by light dispersion when white light meet the prism.

I am updating this post many years later on 27th Aug 2022. The rainbow spectrum shown below is photographed by my 5+ years grand daughter Emma as I sprayed my garden hose onto the white wall of my car porch. The evening sun is behind me and the sunrays create a nice spectrum on the wall.

The most spectacular rainbows I and some friends have ever experienced was in August 1997. We were descending from the peak of Mount Kinabalu. The intense sun rays were behind us and in front of us was a lot of mist. We saw two circular double rainbows ( circular because we were at a very high place and could see the bottom bow of the rainbow as well as the usual top bow). We saw figures in the middle of the rainbows and when we moved our hands, the figures in the middle of the rainbow moved their hands too! That's when we all realized the figures in the middle of the rainbows were actually our shadows cast by the intense sun rays. The sunrays and the mist at this high point formed the two circular rainbows. We all recognized it was a holy moment, orchestrated perfectly by God Almighty in terms of location and weather conditions. Someone did take a photo but back then, photography technology is nothing like now (August 2022) and the photos showed donly the faintest rainbows. However in our memories of the entire group that descended from Mount Kinabalu, that moment is clearly etched in our memories and hearts. God is ever leading us in time and space, whether we are aware of Him or not.

Today 6th September 2022,( 25 years later from the phenomena we experienced together ) I found out the name of the above phonomena that happened to us while we were descending Mout Kinabalu. It is called the Brocken Spectre. No wonder we could see what our shadow silhouttes were doing clearly- the Brocken Spectre explaind the shadows were amplified and it is named a type of glory! Yes! The photo above is credits to https://panoramicireland.com/blog-ireland-guide/croagh-patrick-pilgrimage-brocken-spectre-ringed-glory-irish-mountain

Chan Meng Kit diffraction photo

This photo was taken by Chan Meng Kit - a beloved ex-student in SMK Seksyen 5, Wangsa Maju. I think he snapped it near the school cos' I can see KLCC and KL tower in the background. Again it looks like another pretty picture but the Physics of diffraction is shown so clearly here.

See how the sun light rays spread out after going through the obstacle of the thick clouds.

Take heart - if you are going through some obstacles - you will definitely spread out and grow to have more influence by the time you pass through the obstacles.

Diffraction of white light through the tree leaves

We often see this sort of pic and just enjoy its beauty without realizing this is a picture showing a scientific process called light diffraction.

When light passes through an obstacle like the leaves of the trees here, it will spread out ie the rays near the bottom are much wider than the rays near the top.

Similarly in life, when you face an obstacle - don't be discouraged - if you go through the obstacle - you will experience diffraction and spread out ie become much bigger than before you went through the obstacle.

White light from candle after going through diffraction grating

This is one of the prettiest experiments in Physics forcing white light from a candle or a bulb to go through a little obstacle called a diffraction grating.

What the viewer see now is two rainbow spectrums - one on the left and one on the right side of the white light source - called first order spectrums.

The violet colur is always nearer the centre white light. In the lab we see as many as 16 rainbow spectrums on the left and another 16 rainbow spectrum on the right. Cool right?