real & virtual images

Frankly speaking, I am confused about what is real image and what is virtual image.
So, I have conducted a research on it, hoping that both you and I would understand it.

Real and Virtual Images



Mirrors work by changing the direction that light is moving. In a concave mirror, the light gets reflected towards the center. In a convex mirror, the light moves away. To make an image, we can trace a few rays that the light makes and see what happens to them.


Let’s start with a concave mirror. If the object is far away, the light rays come in, and then bounce and come back together. See the picture below. This is an example of a real image.

If the object is very close to the concave mirror or you use a convex mirror, the light doesn’t come back together. However, if you look at the light that comes off of the mirror and trace it back while pretending the mirror isn’t there, they will come back to a point. This is called a virtual image.

I hope it helps, but it apparantly does not help me. D:

electricity

Old Video and a little "chim".
And a little bit, okay, maybe a lot of chemistry - atoms protons, neutrons.

Reflection

It may be long winded, but it is good for you!

A word of advice, it has got some censor, that when you go to other website, it kind of stops playing.

refraction

I guess this video says it all.
I would be a better explanation then me writing it all out.

How to Help Someone Being Shocked (Tip 101)

Arhhhhhhh!
Someone is ELECTROCUTED!
What should I do?

Stay Calm or you won't be able to do anything!

No need to remember all these steps here, but please please stick a instruction Manuel at home. Preventive measure, yeah!?

Things You'll Need:

• Non-conductive material such as wood, rubber, rope or a cloth

Stopping Electrocution

1. 
   
   Step 1
   Make sure you are NOT wet or standing on a wet surface.
   
2. 
   
   Step 2
   Turn off the source of the electricity. Turning off the appliance may not stop the flow of electricity. You may need to unplug it or even turn off the circuit breaker.
   
3. 
   
   Step 3
   Use non-conductive materials to pull the victim from the electrical source.
   
4. 
   
   Step 4
   Make sure you pull the victim with the object while not touching the one being electrocuted.
   
5. 
   
   Step 5
   Place her carefully on her back and check for breathing and a pulse.
   
   

   Instructions for a Victim Who is Breathing and Has a Pulse

6. 
   
   Step 1
   Perform the following, and then seek help. Call 911 if a phone is near.
   
7. 
   
   Step 2
   Elevate the victim's feet over his head.
   
8. 
   
   Step 3
   Keep him from moving(especially his head and neck).
   
9. 
   
   Step 4
   Loosen his clothing.
   
   

   Instructions to Help a Victim Who is Not Breathing or Lacks a Pulse

10. 
    
    Step 1
    Perform 5 cycles (2 minutes each) of chest compressions on the victim. (CPR)
    
11. 
    
    Step 2
    Call 911.
    
12. 
    
    Step 3
    Recheck for a heartbeat and breathing.
    
13. 
    
    Step 4
    Resume CPR on the victim if the victim is not breathing and does not have a heartbeat. Perform rescue breathing if the victim has a pulse, but is not
    
    
    Tips & Warnings

    • If the victim is vomiting, place her on her side.
    • Do not give the victim anything to drink.
    • Do not apply anything to the burns.

having dry hands - electricity

Touching an electrical appliance with wet hands is dangerous!
Water can conduct electricity.
Also, the resistance of our skin varies from person to person and fluctuates between different times of day. In general, dry skin is a poor conductor that may have a resistance of around 100,000 Ω, while broken or wet skin may have a resistance of around 1,000 Ω.
Tah-Dahs!
Like it?

Electrocuted, scary

Watched the video? Spot the flies too! I am currently finding the person that got electrocuted, inhumane I know, but all for science. However, if you're lucky, you won't be able to watch it. :/ So after watching this video, I've got 1 question to ask. Why did the squirrel got electrocuted when the men didn't? The position of the squirrel and the guy is almost the same, so why the different outcome?



Another one! Look at the "explosion"! It is soooo bright. Thankfully, the guy didn't stand too close to it.



Haha, you are not in luck today, I found the video! You don't need to watch if you don't want. Oh, and the man is a drug addict.

Anyway, the answer is already stated in class. Whether it is human or not, it is not touching the ground or anything connecting it to the ground and thus, the circuit is broken. If we were to touch the pole or the ground, we act like a wire, allowing electricity to flow through us.

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.

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.

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.