How does a match stick be lit up with a magnifying glass?

With a magnifying glass, we are able to focus the sun rays onto a point.
When we place the head of the matchstick on the focus point,
the heat from the rays will light the match stick, causing it to light up.

The head of the match stick contains either phosphorus or phosphorus sesquisulfide,
which will ignite with the heat created from friction or just direct heat.
The sun rays focusing on the head of the match stick is high enough to ignite it.

The above picture is an example of how a magnifying glass is able to focus onto a point,
which is the butterfly.

Picture taken from http://www.goalfinder.com/product.asp?productid=26

Tan Chee Yoong

Physics graded assignments ( reg 35 )

1)How many images would you get for an object that is placed between two mirrors placed at an angle less than 90(degrees)?
The smaller the angle, there would be more images the mirror would produce.

2) What happens to the images of this angle if it is bigger than 90(degrees)?
Similarly, the bigger the angle, there would be lesser images the mirror would produce.

3) How do mirrors produce funny images?Concave mirrors " stretches " your image sideways, causing it to look fat. Convex mirrors however, causes your image to look thin as it is dented in the middle.

Tan Chee Yoong (35)
3e3

Chemistry Assignment ( Reg. 35 )

(1 ) Microwaved food is believed to contain microwaves. How safe is microwaved food ?
Eating microwaved food causes significant changes in blood chemistry over time. A decrease in hemoglobin and cholesterol values, in the HDL (good cholesterol) versus LDL (bad cholesterol) ratio and in white blood cells, weakening the immune system, and an increase in leukocyte levels, which tends to indicate poisoning and cell damage. Eating microwaved foods can cause degenerative diseases or cancer as well.

Microwaves are used in gene-altering technology to deliberately break cells and neutralize their "life-force" so they can be manipulated. Microwaves destroy the life-force that gives food its vitality and nourishment. When this life-force depletes, microorganisms start breaking the food down and will start to rot.

In conclusion, the safest way to heat up your food is to use the stove and not by microwaving.

(2) Reports have linked charred food to cancer. How safe is BBQ food ?
The reports mainly focus on scientific studies involving benz pyrenes. Benz pyrenes are carcinogenic particles found in charred foods. Based on studies with laboratory rats, scientists found that ingesting large amounts of benz pyrenes may cause cancer. The average person would need to eat heavily charred foods at each meal in order to replicate the studies. On average, people eat grilled foods once or twice a week at most. If food is heavily charred, people typically throw it away and start over, or at least cut that part off. In conclusion, BBQ food is quite safe even if you do get your food a little bit charred. People with common sense would just cut the charred part off. If the food gets burnt to a crisp, people would just throw it away and redo it. Thus, chances of getting cancer by ingesting charred food is very slim.

Source(s): http://www.xpeditionsmagazine.com/magazine/articles/kathy/microwave.html and http://www.bbqmyths.com/grilledfoods.html

Tan Chee Yoong
35
3e3

E-learning part 3 ( Reg 31 - 39 )

1. Male seahorses get pregnant! Is this true? How?
Male seahorses do not get pregnant. The male seahorses do not produce the egg themselves. But they receive from the female an "egg sac" which he carries in a a pocket similar to a kangaroo's. The male will then fertilize the eggs when  he thinks that the offspring's chances of survival upon hatching is the greatest. When the eggs gets ejected out of the male, the offspring is left to fend for itself.

2. Sound travels 15 times faster through steel than through the air.Why?
Molecules in a solid are arranged very closely together with little or none spacing at all. While molecules in a gas are arranged far apart with alot of space in between. Thus, sound can travel faster in steel as compared to air.

3. Infants blink only once or twice a minute while adults average around 10. Why do we blink so many times? What is the purpose of blinking?!
Our body is designed to blink often. The brain automatically causes a blink when the liquid film that covers the eye begins to cool the eye that is being open in order to replace the lost liquid. The main purpose of blinking is to lubricate and clean the cornea and the conjunctiva which are the two membranes of the eye.

4. French kissing involves all 34 muscles in the face. Really? Which 34 muscles on the face? Show me a diagram and explain how it works!
Yes a total of 34 facial muscles and 112 postural muscles are used in french kissing.
*P.S Could not find any diagrams for this.

The invention of the magnifying glass

A magnifying glass is a convex lens which is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle. The earliest evidence of a magnifying device dates back to 424 BC Aristophanes "lens" is a glass globe filled with water.

The magnification of a magnifying glass on where it is placed between the user's eye and the object being viewed, and the total distance between the bed in terms of their magnifying power is equivalent to angular magnification. The magnifying power is the ratio of the sizes of the images formed on the user's retina with and without the lens. Thus, the closer the magnifying glass to the eye, the larger the image. The magnifying power obtained in this condition is MP₀=¼Φ+1, where Φ is the optical power in dioptres, and the factor of ¼ comes from the assumed distance to the near point.

I feel that this is a marvelous invention as it enables a person to observe a zoomed-in image of the object. Although the microscope has more focused view, it is not portable unlike the magnifying glass.

Tan Chee Yoong (35)
3E3