Posts Tagged ‘everyday science questions’

Physics is so dear to me, although many students and science teachers alike do not feel good with it. To some, it is boring and full of Maths. Others just do not find it attractive to their intellect, I should say.  But to me, it is full of wonders and an endless chain of discoveries. One of my favourite topics in this field is Space and the Universe.  It appeals to me differently because I feel like watching a movie and doing some reflection at the same time.

Just like the stars that we glimpse in the sky on quite nights, they are full of excitement. They are part of the history that unfolds before our senses, because the stars that you see were actually there many years ago. Stars are light years away from the Earth, and so it would take years for its emitted light to reach us. A light year is a distance that light can travel in one year.  If a ray of light travels in a vacuum in approximately 3×108 m/s, the ray of the sun which distance from the Earth is approximately 150 million kilometres could reach the Earth in eight minutes, how much more for distant stars? (more…)


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The sky is blue especially during bright days due to Rayleigh scattering. This scattering is the elastic scattering of electromagnetic radiation including light, by particles much smaller than the wavelength of the light. It can happen notably when light travels through gases or air. Rayleigh scattering of sunlight results in diffuse sky radiation, which is primarily the reason why the sky is blue and the sun look yellow.

As light travels through the atmosphere, most of the longer wavelengths just pass through straight away whilst some of the red, orange and yellow light, is affected by the air. Much of the shorter wavelength light, like the blue wavelength, is absorbed by the gas molecules, which is then radiated in different directions. It scattered all around the sky and so the blue colour seemed to occupy much of the sky.

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How can you get salt from a rock salt or seawater? This is a simple classroom demo to show that the common salt in the kitchen is mined from underground or can be taken out from the seawater. (more…)

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An activity that can be done as a class experiment. Just make sure materials and equipment are available for the students.  If not readily accessible in your school, ask groups to bring in materials.

This activity can be used when discussing about the importance of water.  As a springboard of the topic, prepare pictures or powerpoint slides on water pollution, water scarcity in different parts of the world, sources of water, and etc.  When it rains, water penetrates into the ground and as it passes through it, the water is filtered by the rocks, and sand, and soil, and eventually comes out as clean water at a spring or wells. (more…)

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