Thursday, 8 December 2011

Toatal Lunar Eclipse -10 Dec 2011

Total Lunar Eclipse – 10 Dec 2011

Imagine you are outside your house breathing some fresh air and enjoying the night view around you. You look up at the sky, hoping to catch a star or two, but what you saw instead was a reddish orangey full moon hanging in the sky. What happen to our Moon?!?
No fear, there is nothing wrong with our Moon – our Moon is as normal as it always is. It’s just passing through the Earth’s shadow, and we call that a lunar eclipse.
This is going to happen on Saturday (Dec 10), on a convenient time for us (in Malaysia). The Moon starts to enter the penumbral shadow at 7:33 pm and exit by 1:30 am the next day, with maximum eclipse at around 10:30 pm. This means that we no need to stay up late into the night to see it.

Credit: F. Espenak, NASA’s GSFC
For animation, click here. As you can see from the animation, as the Moon enters the Earth’s penumbra (P1 to U1), you may not observe any changes. The show really starts after 8:45 pm (U1), when the Moon starts to enter the umbra shadow. Look for the colour change (to reddish) as the Moon moves deeper and deeper into the shadow. Between 10:06 pm (U2) to 10:57 pm (U3) is what we called totality – this is the time when the whole Moon is in Earth’s umbra. After that, the Moon will slowly come out from the shadow, and by 1:30 am, you can pack and go to sleep.

Total Lunar Eclipse of 16 Jun 2011 taken outside my house. I did not managed to finish the whole sequence because the clouds rolled in. Credit: thChieh.

Why does the Moon turns reddish or orangey during totality? Shouldn’t it disappear as it enters the Earth’s shadow? The reason is our atmosphere. Take a look at the diagram below and it’ll explain everything.

If the Earth had no atmosphere, the Moon would be completely dark during an eclipse. The presence of Earth’s atmosphere means that sunlight reaching the Moon must pass through a long and dense layer of air, where the light is scattered. Shorter wavelengths (blue) are more likely to be scattered, so by the time the light has passed through the atmosphere, the longer wavelengths (red) dominate. The scattering depends on the conditions/particles in our atmosphere, which in turns determine the colour of the totality Moon. Anything from bright orange to blood red is possible. If there has been a major volcanic eruption, for example, the atmosphere has so much dust that the shadow on the moon will appear dark throughout an eclipse.
What colour are we going to see this Saturday? It will be a surprise…
(When the eclipsed Moon is bright, the stratosphere is clear. On the other hand, a dark eclipse indicates a dusty stratosphere. There are atmospheric scientists out there who are studying lunar eclipses as a means of monitoring conditions in Earth’s upper atmosphere. How cool is that?)

But don’t just look at the red. A more not known colour is the turquoise blue. I’m not sure if it is visible to the naked eye, but I’m sure if you take a picture of it, you will see it (see picture below). This comes from light passing through the ozone layer, which absorbs red light and makes the passing light bluer. This can be seen as a soft blue fringe around the red core of Earth’s shadow. Start looking for the turquoise colour as the umbra eclipse begins (U1), it will be more obvious as the Moon moves into shadow, or when starts to come out of the shadow.

Total Lunar Eclipse of 16 Jun 2011 taken outside my house. The Moon had just fully entered the unbral shadow (U2). The top part is darker because it was deeper in the shadow; the bottom part is bluish due to the reason described above. Credit: thChieh.
If you are in an area without much light pollution, you can actually see the stars around the Moon during totality. Usually the bright full moon will drown all the stars around it, but during a totality, you can take picture of the full moon with the stars.
Go out and take a look at the Moon after dinner this Saturday, you won’t want to miss it, because this will be the last total eclipse until year 2014. Yes, you read it right. There will not be any total lunar eclipse for two whole years. So grab this last opportunity!

Sunday, 4 December 2011


Untuk memuat turun sila klik link di bawah :-
Kertas Kerja Lawatan Sambil Belajar Panitia Sains

Modul PEKA Sains

Download Modul PEKA Sains

PEKA Science Year 6
* Sila klik pada link di atas.

Peta Minda Sains

Laman Web Peta Minda Sains ini sedikit sebanyak dapat membantu para guru serta murid bagi lebih memahami Sains Sekolah Rendah. Semua peta minda ini berbentuk E-Book. "E-Book" atau buku elektronik bukanlah satu buku berbentuk fizikal. Buku elektronik adalah buku dalam bentuk digital atau fail komputer dalam format PDF. Ia hanya boleh dibuka dan dicetak oleh program Acrobat Reader.

Dalam proses pengajaran dan pembelajaran, peta minda telah diakui sangat berkesan digunakan dalam bilik darjah.  Ini adalah kerana peta minda yang telah disediakan oleh guru sendiri dan diedarkan kepada murid dengan sendirinya menjadi nota mereka tanpa perlu mereka membuat nota sendiri.  Penggunaan LCD serta perisian komputer yang boleh membesarkan paparan di skrin dengan kemudahan "zoom" memudahkan lagi proses pengajaran dan pembelajaran.

Peta minda juga lebih memudahkan anak-anak murid serta anak-anak anda mempelajari, menghafal dan menyemak pelajaran sains sebagai persedian sebelum  menduduki peperiksaan UPSR.

Sila klik ke Peta Minda Sains

Wednesday, 5 October 2011

NASA | Lunar Eclipse Essentials


Balancing Nails on a Nail
Pound a large nail far enough into a board so that the nail stands securely upright. Lay a second large nail on a flat surface and place other nails across this nail, head to head as shown above. Finally, place another nail on top of this assembly, head to tail with the second nail. Carefully pick up the assembly and balance it on the upright nail.
In a gravitational field, any object is most stable when its center of mass is as low as possible. The center of mass of the nail assembly is below the point of support and at its lowest when the assembly is balanced. If the assembly swings to the side, its center of mass rises. Gravity that exerts a restoring force to bring the assembly back into balance.
Rolling Coin in Balloon
Place a coin in a large balloon, and then inflate and tie off the balloon. Swirl the balloon rapidly to cause the coin to roll inside the balloon. The coin will roll for a very long time on the smooth balloon surface. At high coin speeds, the frequency with which the coin circles the balloon may resonate with one of the balloon's "natural frequencies," and the balloon may hum loudly.
Racquet Ball Conserves Energy!
With a sharp knife or razor blade (caution!!!), slice a racquet ball into two halves. Trim each half so that it is slightly smaller than a hemisphere. Turn the he hemisphere inside-out and drop it, bulge-side-up, on a hard surface. The ball will snap and rebound to a height much greater than that from which it was dropped.
Work is required to turn the hemisphere inside-out and this work is stored as potential energy. As the dropped ball hits the hard surface, this potential energy is released and converted to kinetic energy, allowing the ball to rebound to a greater height.
Balancing a Ball with a Hair Dryer
A light ball, such as a ping pong ball or Styrofoam ball, can be balanced in the air stream of a hair dryer. According to Bernoulli's Principle, the pressure in the fast-moving air stream is less than the pressure of the surrounding quiet air. If the ball strays from the air stream, the surrounding higher pressure air tends to push it back.
Dinner Table Optics
Use a filled round-bottom wine goblet as a lens to focus the light from a candle or from the filament of a chandelier bulb onto a wall. How does the image on the wall compare to the original object?
Look carefully at the world through the wine goblet. Then look carefully at the world through a beer mug. How are the optics of a wine goblet and beer mug similar? Different?
Use a large shiny spoon as a mirror and compare your image in the bowl and back of the spoon. Observe carefully the image of your pointed finger as you move it toward the bowl of the spoon until it touches the spoon.

A Simple experiment for kids ~ baking soda+vinegar

The Science Symbols