Friday, January 15, 2010

the spectrum of colours

Hello people!
Today's post shall be short and sweet.
Anyway, the question is:
Why is the red at the top of the spectrum of colours, and the violet at the bottom?

I came across a website that states that instead of having the red at the top, the red is at the bottom and the violet is at the top. This pictures shows how.



But in any case, the same website also states that the wavelength and frequency of light we see, also influences the colour we see. The seven colours of the spectrum all have varying wavelengths and frequencies. Red is at the lower end of the spectrum and has a higher wavelength but lower frequency to that of Violet. Whereas Violet, located at the top end of the spectrum, has a lower wavelength and higher frequency.




Frequency
The frequency of a wave is determined by the number of complete waves, or wavelengths, that pass a given point each second.




However, another websites says that "Red light has the longest wavelength in the visible spectrum and therefore reflects the least. It is found at the top of the visible spectrum. Violet light has the shortest wavelength in the visible spectrum and therefore reflects the most. It is seen at the bottom of the spectrum." So Basically, it is because of the length of the wavelength in this website, and both the length of the wavelength and frequency in the first website, that explains why the red is at the top and violet is at the bottom, vice versa.

And, another website also stated that red has the longest rays and in this case, violet has the shortest rays, so tah-dahs!

Hope it is not confusing.

Friday, January 8, 2010

glycerin + test tube = disappear

Hello!

So, Mr Lim showed us that experiment and here am I, explaining why it happens and hoping that it is correct.
I guess I don't need to explain the experiment, so people, base it on your memory!
Haha.

Anyway, firstly, before we proceed, this is what glycerin is.

Glycerin:
- Attracts moisture to your skin.
- It is a natural by-product of the soapmaking process and while commercial manufacturers remove the glycerin for use in their more profitable lotions and creams, handcrafted soap retains glycerin in each and every bar.
- Glycerin is a neutral, sweet-tasting, colorless, thick liquid which freezes to a gummy paste and which has a high boiling point.
- Glycerin can be dissolved into water or alcohol, but not oils.
- Many things will dissolve into glycerin easier than they do into water or alcohol. So it is a good solvent.
- It is also highly "hygroscopic" which means that it absorbs water from the air.
- It softens the skin

Oh, and I found a video of the experiment, hope you enjoy it!



Explanation:
What happens is that the glycerin and the bottles have the same refraction index/optical density. Because the light that is going through the glycerin and the bottles is just as easy in both, your eye can't see any different between them. Normally you would see the bottle by the shape in water. But you can't here, that's why it looks like it disappear! Still you can see the glass bottle in the drinking glass. There is a narrow gap between the tow, clearly visible. If it was water, the gap would be much wider and the bottle easier to spot.

OR

Light breaks through glass at the same angle as it does in glycerin.

Tuesday, January 5, 2010

gloves, the ultimate no censor item

Hello people!
Stella is back again for more science, and how are you people doing?
As you can see, I have relinked, so, please relink me!
Just some "important" announcements to make (above).
Anyway, as you people all know, we have 2 new questions on the waiting list (finally), and here is the answer.


Q1: Why can't the lift activate when we use gloves to touch the touch-screen panel and those normal button?


Wows, this is one such difficult question to answer. All I got from searching the web is jokes, escape games formula, and nothing about what I want to search about. Give me a moment to find it. Frankly speaking, I think I have experienced this before and never wondered why this would happen. Since I still got the same results as just now, I shall tell all of you what I think. I think that it is because of the pressure produced from our pressing. You see, the gloves are quite thick (you need to keep your fingers and hand arm, isn't that what it is supposed to do?) and as we exert the pressure, the pressure is "spreaded" around the many layers of fibres that make up the material of the gloves and thus, the end amount of pressure that is applyed to the button (please be mindful that I am talking about those normal kinds of button that we press) is so little that is just isn't enough to be the exact amount of pressure needed to push the button.


Can you imagine the buttons being so loose? Let's count how many trips the lifts need to travel up and down. As for the touch screen panel, I seriously am clueless about how it works. I guess it works a little like how the button works. The pressure applied on the panel is too little as compared to a person pressing the panel without any gloves. So, that's it for this question. I seriously have no idea if it is correct. It is just my assumption. Correct me if I am wrong, I am open to correct, but not too harsh a critism.





Just imagine it pressing a lift button. Sorry, I can't photoshop it. :(


Q2: Why ice sticks to your hand/finger when it is just taken out of the freezer?


It is basically due to some simple processes that we have learnt before, but never thought that it can actually be found in simple things like this. When ice is taken from the freezer, it is about -15 degrees C. The moment it comes in contact with a moist surface, like your finger or tongue, the water that had already melted due to the temperature change, instantly becomes frozen to the surface of the ice. This effect causes the ice to feel, "sticky." Once the ice warms up to 0 degrees C, it is no longer sticky since the surface is starting to melt, leaving a layer of liquid between your finger and the ice.


See, it really is made up of simple processes. It is just that... Anyway, now that you know, I hope it enlightens your questions, if you ever had taught of this question.