SCORE REPORTING - INTERPRETATION OF SCORES

The nursing schools that use the pre-NLN exam set their own admission criterion. They set the minimum pass score and percentile rank.

Click here to have an idea of the type of scores report.

Raw scores is how many questions you got right out of the questions you were given. For example, for verbal, if you get 44 out of 60 questions right, then your raw score will be 44 out of 60.

The percentile ranks are based on all those who took the test at some specified point in time. The percentile scores/ranks are reported under the following:

DI = students who took the exam who were applying for a diploma program.
AD = students who took the exam who were applying for an associates program.
All = students applying to schools that can grant an associates or a BSN.

The numbers underneath each of them is a percentile not a percentage - it's how much better you did compared to other students who took the exam.

For example, if the percentile under AD, for verbal is 75 - it means that you are in the 75th percentile.This means that you did better than 75% of the people that took the test in verbal who were applying for an Associates program, in other words, 25% of the people did better than you. Likewise, if for math, under AD, you got a 90 - you are in the 90th percentile - you did better than 90% of the people that took the test in math who were applying for an Associates program. In other word, 10 % of the people did better than you.

For composite scores:The composite score range is 0-200. The composite percentile will always be 99 or lower. You really can't get 100 because then you'd be scoring better than yourself. 100 is average and most students score around 100. To crack past 150 is quite difficult for most students. You would either have to get almost every question right. Getting between 125-135 will put you in the top 10%

Composite scores are also reported for verbal, math, and science - for these scores, 100 is the highest you can get, 50 is the average, and 1 is the lowest you can get. 

Here is a sample score:

                                             Percentiles
                     Raw Scores      DI     AD    ALL 
         Verbal:      44/60           87     80     80
         Math:        36/40            98     97     97
         Science:    42/60            93     89     88

Composite Score: 135            97    93    94 (Composite Percentile Score)

In general, if you get two-thirds of questions right in each subject area, you can guarantee yourself a percentile above 70. 

GAS LAWS

The following are the basic laws that govern the behavior of gases.
1. Boyle's law: This states that at a constant temperature, the pressure of a gas is inversely proportional to its volume. This means that as the pressure increases, the volume decreases and vice versa.

(Initial Pressure) x (Initial Volume) = (Final Pressure) x (Final Volume)

Examples: 

• As the pressure in a balloon is increased, it expands continuously until it can no longer do so and then burst open. 
• Air rushes into the lungs from outside when the chest cavity expands to increase its volume because the pressure within the thoracic cavity decreases. When the volume of the thoracic cavity decreases, the intra-thoracic pressure increases and the air is pushed out. 

2. Charles' law: This states that at a constant pressure, the volume of a gas varies directly as its temperature. This means that when the temperature increases, the pressure also increases and vice versa.

   Initial Volume      =   Final Volume      
Initial Temperature       Final Temperature

Examples: 
If you increase the temperature on a balloon at atmospheric pressure, the volume increases as well.

3. Gay-Lussac's law: This states that at a constant volume, the pressure of a gas varies directly as its temperature. This means that when the temperature increases, the pressure also increases and vice versa.

   Initial Pressure      =   Final Pressure      
Initial Temperature       Final Temperature


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TEMPERATURE CONVERSIONS

Here are the formulas for converting from one temperature unit to another.

C is Celsius
F is Fahrenheit

K is Kelvin 

1.   C = 5/9 (F-32) or C = (F-32)/1.8

2.    F = 9/5 (C+32)  or  F = (C+32)*1.8

3.    K = C + 273

Note that the Kelvin temperature has no negative values. 

PHASE DIAGRAMS AND PHASE CHANGES

What is a phase diagram?
Phase diagrams show the preferred physical states of matter at different temperatures and pressure. Within each phase, the material is uniform with respect to its chemical composition and physical state. 





Click on this for "Practice exercise on phase diagram"
Click here for the Answers to practice exercise

PHASE CHANGES
This is a link to a website that has a good explanation on phase changes of water. I recommend that you read it. It will be good to memorize and understand what happens in the various regions. Note that when there is a change of state, the temperature remains unchanged for sometime.

Diagram of phase changes

QUESTIONS FOR THE DAY

1. Calculate the amount of heat needed to increase the temperature of 250g of water from 20^o C to 56^o C. Specific heat capacity = 4.18 J ^oC^-1 g^-1
   
2. Calculate the specific heat capacity of copper given that 204.75 J of energy raises the temperature of 15 grams of copper from 25^o C to 60^o C.
   
3. 216 J of energy is required to raise the temperature of aluminium from 15^o to 35^oC. Calculate the mass of aluminium. (Specific Heat Capacity of aluminium is 0.90 J^oC^-1g^-1).
   
4. The initial temperature of 150g of ethanol was 22^oC. What will be the final temperature of the ethanol if 3240 J was needed to raise the temperature of the ethanol?
   (Specific heat capacity of ethanol is 2.44 J^oC^-1g^-1).
   

Answers:

1. q = 250 x 4.18 x (56 - 20) = 37,620 J or approx. 38 kJ
2. 204.75 = 15 x C x (60 - 25)
   C = 0.39 J^oC^-1 g^-1
   
3. 216 = m x 0.90 x (35 - 15)
   m = 216 ÷ 18 = 12g
   
4. 3240 = 150 x 2.44 x (T_f - 22)
   T_f = 30.9^oC

QUANTITY OF HEAT

The quantity of heat energy (Q) gained or lost by a substance is equal to the mass of the substance (m) multiplied by its specific heat capacity (C) multiplied by the change in temperature (final temperature - initial temperature)

Q = m x C x (T_f - T_i)

Memorize this formula well.

• Specific Heat Capacity (C) of a substance is the amount of heat required to raise the temperature of 1 gram of the substance by 1^o C (or by 1 K).
• Heat capacity (H) is defined as the mass multiplied by the specific heat capacity.        H = m x C
• The quantity of heat can therefore be defined as heat capacity multiplied by the change in temperature. Q = H x C

Example:

Calculate the quantity of heat needed to raise the temperature of 250 grams of water from 20^o C to 56^o C. (Heat capacity of water is C_g = 4.18 J ^oC^-1 g^-1)

Solution: Q = m x C x (T_f - T_i) 

m = 250 g; T_f = 56^oC; T_i = 20^oC

q = 250 x 4.18 x (56 - 20) 

q = 250 x 4.18 x 36 

q = 37620 J = 38 kJ

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MODE OF HEAT TRANSFER

Heat is a form of energy which transfers between bodies which are under thermal interactions. Heat transfer occurs when a temperature difference occurs between two bodies or a body with its surroundings. 

There are three modes of heat transfer:

1. Conduction
2. Convection and
3. Radiation

CONDUCTION: Conduction is the mode of heat transfer which occurs from one part of a substance to another part within the substance itself or with another substance which is placed in physical contact. 

CONVECTION: Heat transfer occurs within a fluid itself and it is carried out by transfer of one fraction of the fluid to the remaining portion. 

RADIATION: This mode of heat transfer does not require any medium to occur. Every matter with a temperature above absolute zero will emit energy in the form of electromagnetic waves called radiation.

Illustration of modes of heat transfer.

Illustration and summary of modes of heat transfer

GERMINATION OF SEEDS

1. The seed contains the embryo of the new plant.
2. It has a supply of food for the embryo until it has formed sufficient roots and leaves to obtain its own food. 
3. The food, referred to as the endosperm, may be in the seed leaves (called the cotyledons) or it may be outside the seed leaves.

4. To germinate, the seed leaves absorb water and swell, and the seed roots (called radicle) emerges, followed by the seed shoot (called plumule).

Parts of the seed.

Pollination and fertilization

PARTS OF A FLOWER

The flower has a male and female parts. These may be on the same flower or on different ones. Below are the various parts of a typical flower.


1. The male part of the flower is called the stamen and it consists of the anthers and filaments. The anthers contains the pollen grains.
2. The female part of the flower is called the pistil. It consists of the stigma, the style, ovary and ovule.
3. The stigma is sticky and it attracts the pollen during pollination.
4. Pollination is the transfer of pollen from the anthers to the stigma. It may be self or cross-pollination. Self-pollination involves the same flower whereas, cross-pollination involves different flowers.
5. The pollen grows through the style into the ovary to fertilize the ovule.
6. Fertilization leads to seed production and embryo formation. So the seed is the fertilized ovule.
7. The petals are colorful and they attract the agents of pollination such as bees, butterflies, etc.
8. The ovary wall becomes the fleshy part of the fruit.

This diagram summarizes the functions of the various parts. 

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GENITOURINARY SYSTEM

Under this topic, we will discuss the structure and functions of the kidneys, ureters, bladder, and urethra. This system produces urine.

1. Kidneys: These are bean-shaped organs that are about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. The kidneys basic functional unit of the kidney is the nephron. 

2. The nephrons produce the urine. Every day, a the kidneys process about 200 quarts of blood to filter out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. 

3. The ureters are the narrow tubes that carry urine from the kidneys to the bladder. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters. 

4. The bladder stores urine until it is released  through urination. 

5. The urethra is a tube which connects the urinary bladder to the outside of the body, and carries semen in men, and urine in women and men. 

6. The external urethral sphincter is a muscle that allows voluntary control over urination.

STRUCTURE OF THE NEPRON

Diagram of nephron

The nephron consist of the:

1. Bowmans capsule: This is the cup-like structure that house the glomerulus (tuft of capillaries). Filtration of the blood occurs in the glomerulus. This is the first step in the urine production.

2. Proximal convoluted tubule: Re-absorption of nutrients filtered out occurs here. This include glucose, calcium, potassium, water, and amino acids.

3. Loop of Henle; Pumping out of sodium and water occurs here.

4. Distal convoluted tubule: Secretion of into the urine of hydrogen and potassium occurs here.

5.  Collecting duct:  More water is pump out here leading to urine concentration.

Diagram summarizing the functions of the nephron.