Isotopes!

Welcome back to the next series of Atoms! I really hoped you had fun in reading the previous post! Anyway, due to time constrain, I have fast forward the lesson to Isotopes!

So what exactly are Isotopes???? Hmmm...

Atoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopes.

Refer to the previous post to recap on what is Neutron! :)

Hydrogen

The most common isotope of hydrogen has no neutrons at all; there's also a hydrogen isotope called deuterium, with one neutron, and another, tritium, with two neutrons.

You might now wonder how many Isotopes can 1 element have.

Well, sad to say that an atom cannot just have any number of neutrons. There are combinations of neutrons and protons, at which the forces holding nuclei together seem to balance best. Atoms with a few too many neutrons, or not quite enough, can sometimes exist for a while, but they're unstable.

So what is unstable in the above question?

Unstable atoms are radioactive: their nuclei change or decay by spitting out radiation, in the form of particles or electromagnetic waves.



Radioisotopes/ Radioactive Isotopes

That question above ^^^^^ leads me to the next topic, called radioisotopes!

It is well, sad to say that Radioisotopes are really really really (I mean really) dangerous.!!!

Because the like charges of the protons repel each other,there are always forces trying to push the atom nucleus apart. The nucleus is held together by something called the binding energy.


In most cases, elements like to have an equal number of protons and neutrons because this makes them the most stable. Stable atoms have a binding energy that is strong enough to hold the protons and neutrons together.

Even if an atom has an additional neutron or two it may remain stable. However, an additional neutron or two may upset the binding energy and cause the atom to become unstable.

In an unstable atom, the nucleus changes by giving off a neutron to get back to a balanced state. As the unstable nucleus changes, it gives off radiation and is said to be radioactive.

I'm sorry to say that the picture isn't clear, but I can tell you that it is giving out radioactive waves...Reminds me of the Bombing at Nagasaki. 0-0

Other facts

You'll get why I am showing you the Table :)

All elements with atomic numbers greater than 83 are radioisotopes meaning that these elements have unstable nuclei and are radioactive.

Elements with atomic numbers of 83 and less, have isotopes (stable nucleus) and most have at least one radioisotope (unstable nucleus).

As a radioisotope tries to stabilize, it may transform into a new element in a process called transmutation.

Uses of Radioisotopes

Shocking?!?!?! Yes, it can be used in medication you know! -Feign shock-

One major use of radioisotopes is in nuclear medicine. Of the 30 million people who are hospitalized each year in the United States, 1/3 are treated with nuclear medicine.

There are nearly one hundred radioisotopes whose beta and/or gamma radiation is used in diagnosis, therapy, or investigations in nuclear medicine. The most used radioisotopes were discovered before World War II.

Chemistry.....Atoms!

Wasssssssssssssup People! It's officially chemistry for this term! One last term before the EOYs! But anyway, I'm here to tell you more about atoms, and not here to make you depressed by telling you that the next term is the EOYs.

So anyway, let me give you a brief overview of the whole topic on Atoms...I guess. :)

So I'm sure you will ask, what are Atoms?

Before I start on anything official here, please do read up on elements. It will help you greatly in the first part, which is now. :)

All elements are made up of Atoms.

This picture below shows what scientists have found, the shape I mean.

The picture above shows the interior of an atom. Fasinating isn't it?

You might be wondering what are the headings there, and it's quite easy to understand actually.

The nucleus of an atoms consists of Protons, and Neutrons. Protons are POSITIVELY CHARGED, while Neutrons are NEUTRAL.

Electrons are the small little particles orbiting the nucleus. They are NEGATIVELY CHARGRED.

The picture below might actually help you! :)

However, if you have taken a good look at the periodic table, you are able to see that there are over a HUNDRED elements. And each element has a different number of neutrons, protons, and electrons.

Now, how do you know which number is the proton number (atomic number), and which is the mass number (made up of protons, and neutrons)?

So let me tell you again, if you didn't quite understand what I was talking about.

Mass Number

-Usually at the top left hand of the element box (right in this case)
-Made up of Protons, and Neutrons

Atomic Number

-Usually at the bottom left of the element box (right in this case)
-Number of Protons

Facts

You might have noticed that although it is the same element, the mass number is different, but it's not any typo error. There is a scientific explanation behind it. The element here is Carbon. In this case, carbon is in different proportions, and that is why the mass number is different, but it is still carbon in any case.

Digestion - Alimentary Canal

Hey Sup People! How are you doing this afternoon? Hope you are doing gggggggggrrrrrrrreeeeeeeaaaatttt! (GREAT)

Okay, enough of the introduction :) So today's topic is also about Digestion, but we're moving on to another topic, the Alimentary Canal. I know you must be thinking: "Hey we've learnt this before! Why are we learning this again?" Yes I know that question very well, but here, we're going in dept about all the organs, and stuffs.

So let me list out the enzymes the substrates, and the end product.

Carbohydrate

Starch ( Salivary Amylase) Maltose
Maltose (Maltase)             Glucose

Protein

Protein          (Pepsin)               Polypeptides
Polypeptides (Erepsin/Trypsin) Amino Acids

Fats

Fats      (Bile)     Emulsified Fats
E. Fats (Lipase) 3 Fatty acids + 1 Glycerol

Okay, so now you've seen all the reactions, let's get down to all the organs in the alimentary canal, and their functions. Please get your paper and pens/pencils ready, for the next few paragraphs would be a rollercoaster ride. (0_0 That's exaggerating)

Mouth

• Contains teeth that chews food molecules into smaller food substances so that it would have a larger surface area for more enzymes to act on it
• In here, starch is digested by the salivary amylase to form maltose
• The saliva secreted by the salivary glands produces the enzyme, and it also softens, and mixes the food
• The tongue rolls the partially digested food into a bolus before it is being swallowed down.

Oesophagus

• It is also known as the gullet, but at this level, it should be called the oesophagus
• No digestion takes place here
• There are 2 muscle that aids in Peristalsis (The next point) - the longitudinal muslce, and the circular muscle
• Peristalsis - The rhythemic wave-like contraction of muscles that propels and mixes the contents of the alimentary canal forward

Stomach

• The stomach is an elastic, muscular bag with thick elastic walls.
• It secretes a mixture of gastric juice - hydrochloric juice, pepsin, and rennin
• The stomach contracts and relaxes so that the foods are well mixed with the gastric juices
• In here, protein is being digested in polypeptides by the enzyme pepsin
• The end product is a semi-liquid product called chyme, that is being released into the duodenum, the first part fo the small intestine.
• The interesting thing about a stomach is that it is the only organ which has a pH value of 2 (refer to the previous post about pH values)

Liver, Gall Bladder, Pancreas 

Digestion - Enzymes

Hey's People, I'm back after a break, if you can see the timing. But anyways, here's the 2^nd part of the mighty digestion! (Y) The.....*Drum Roll Please*.....Enzymes! (Y)

Anyway, Enzymes are really simple to understand, but you have to remember a lot of things, but if you write it all out on 1 piece of foolscap paper, I guess you'll remember it better, by a lot, so anyways, good luck!

So Here's the Definition of enzymes.

Enzymes are Proteins. (Please remember that) They are biological catalysts that help speed up the rate of chemical reactions without themselves being broken down at the end of the reaction. (How cool is that?)

Enzymes - Conditions

Yes, there are conditions, like the T&Cs that we humans have. There are 2 main conditions for the best enzymes reactions, and I think you'll find it easy to remember. :)

1. Optimum Temperature

It basically means the temperature at which the enzymes works best in, which is room temperature of about 37 degrees or so (plus minus) and some questions usually states 40 degrees, which is also considered. At this temperature - room temperature - the enzymes reactions with the substrate is at it's peak, but after that temperature, the enzymes would slowly denature, meaning that the reactions would become slowly, and the enzymes would slowly die.

However do please take note that in scientific terms, the enzymes do not die but denature.

2. pH Values

Sorry to say that we have not learnt Chemistry as we would be learning it the next term, but I guess it is just the acidity and the alkaline, and in this case, it is the pH values of the enzymes.

salivary amlase works best in pH7
protease works best in pH2
lipase works best in pH 7~8

Digestion - nutrients

Heys People! I know I'm posting at such a late date, but at least I posted....right? Anyways, here is what I think is the summary of digestion. I've summarised the points I think is required for the exam, as well as adding in several other informations I think it would be fun to know, maybe. But anyways, here it is!

Digestion is basically just the breaking down of large, insoluble, indiffusible food substances into smaller, soluble, and diffusible food substances.

Easy to remember...right? Yeahs.

So anyways, there are 3 types of nutrients in total - carbohydrates, proteins, and fats.

Carbohydrates:

It provides energy for the body cells.

There are 3 types of carbohydrates, mainly the diasaccharides, monosaccharides, and the polysaccharides. I would not go into detail for that as you people have to study!!!

So anyways, there are 2 type of tests for carbohydrates, the Benedicts Test and the Iodine Test.

It is made up of Carbon, Hydrogen, and Oxygen (CHO)

Benedicts Test:

It tests for reducing sugar, and if reducing sugar is present, the solution would become reddish (is there even such a word?) -orange precipitate. If not, it would just remain as blue.

Iodine Test

It tests for, as you all should know, for starch. So, if starch is present, the solution would turn blue-black, or if starch is not present, then the solution would remain brown/yellow, depending on the colour of the iodine at first. But I guess it would be better if you choose brown instead, to you know, just to play safe XD

Protein:

It is the main substance used for the growth of new cells, and the repair of damaged cells. It also provides energy when the body lacks fats, or carbohydrates.

It is made up of Carbon, Hydrogen, Oxygen, and Nitrogen.

Protein can never never be stored as it is TOXIC!!!! Thus, it is removed by the body via egestion, as urea in urine.

Biuret's Test

The biuret test is used to test for the presence of protein. If protein is present, the solution would change to violet (yeah!!! 0_0). If not, it wouls remain as blue.

Raw or cooked food?

So I'm back, finally I guess, from the terrible terrible 1 week holiday. Anyway, let's get back to the topic on hand. Oh, and 1 more thing, welcome to the era of Biology! .......

You know, I love sashimi so this would be quite an interesting topic to research on. Maybe if the results shows that raw food digest slower, I would consider going all cooked food. -_____-"'

According to a certain website, it states that raw food does not digest as easy as cooked food, thus if you want to feel full, do eat more cooked food, unless you're somehow on a diet.

It is believed that your body's own elimination system can eliminate all or most of the toxins in the cooked portion of your diet when eating more raw food. When you eat more cooked food you are eating toxins faster than your body can get rid of them so they back up causing disease.

While searching, I came across this websites that answers the second question- Should we eat raw food or cooked food?

Raw foods are rich in enzymes. Enzymes are needed for the digestive system to work. They are necessary to break down food particles so they can be utilized for energy. The human body makes approximately 22 different digestive enzymes which are capable of digesting carbohydrates, protein and fats. Raw vegetables and raw fruit are rich sources of enzymes.

Lack of digestive enzymes can be a factor in food allergies. Symptoms of digestive enzymes depletion are bloating, belching, gas, bowel disorders, abdominal cramping, heartburn and food allergies.


All of us loose our ability to produce concentrated digestive enzymes as we grow older. In cases where age is a factor, or where lack of digestive enzymes causes food allergies, supplementation may be helpful.

The more food that you can eat raw, the better.

If you do cook your food, the best way to cook food is to lightly steam, stew, or use a slow crock cooker. Eat as few over-processed and over-cooked foods as possible. The body has a difficult time digesting fried, pasteurized, barbecued, dried, and other over-processed and over-cooked foods which you find in boxed and processed foods.

Cooked food undergoes cooking (that's why it's called cooked food duhh..) and it uses heat. Enzymes are then destroyed in heat and it chemically changes foods from the substances needed for health into free-radicals and poisons that destroy our health!


. Enzymes are importanttt...

Therefore, the author of this blog strongly recommends raw food. Ye-ah. I love (L) raw food!

refraction

Refraction is here to be with his buddy! Anyway, let me start.

Refraction has lots to remember as compared to reflection.

This illustration basically means:

•The ray of light which travels through the incident, or first, medium and strikes the boundary, or interface, is called the incident ray.


•The ray of light which travels into the refracted, or second, medium and leaves the interface is called the reflected ray.

•A line perpendicular to the surface is imagined at the point of refraction. This line is called a normal. In this context the word normal means perpendicular. In the above diagram the normal is colored blue.

•The angle between the incident ray and the normal is called the angle of incidence, or the incident angle.

•The angle between the refracted ray and the normal is called the angle of refraction, or the refracted angle.
 

This picture means that the ray would bend towards the normal when it is travelling in a denser medium.

This picture means that the ray bends away from the normal when it is travelling in a less dense material.

reflection

Stella's back for more, this time with reflection! It's buddy, refraction, will be accompaning him later on, on the next post.

This picture says it all, right?

It basically means this

•The ray of light which strikes the surface is called the incident ray.


•The ray of light which leaves the surface is called the reflected ray.

•A line perpendicular to the surface is imagined at the point of reflection. This line is called a normal. In this context the word normal means perpendicular.

•The angle between the incident ray and the normal is called the angle of incidence, or the incident angle.

•The angle between the reflected ray and the normal is called the angle of reflection, or the reflected angle.

Notice that the angle of incidence is = to the angle of reflection.

There is this website - click here - that shows how a light beam reflects at the surface of a flat mirror. It is an animation. Simple, but it may explain it to you. Scroll down the website and you'll see the animation.
 
Have fun!

rainbows

I know I am late for this post since this topic was ages, ago, so I was thinking why not a recap! It won't hurt, would it?

Rainbows are one of the most spectacular light shows observed on earth. Indeed the traditional rainbow is sunlight spread out into its spectrum of colors and diverted to the eye of the observer by water droplets.


Most people have never noticed that the sun is always behind you when you face a rainbow. I understand it is funny but it is true.


The traditional description of the rainbow is that it is made up of seven colors - red, orange, yellow, green, blue, indigo, and violet. Actually, the rainbow is a whole continuum of colors from red to violet and even beyond the colors that the eye can see. Thank God we only have to learn the 7 colours. :D

The colors of the rainbow arise from two basic facts:

Sunlight is made up of the whole range of colors that the eye can detect. The range of sunlight colors, when combined, looks white to the eye. This property of sunlight was first demonstrated by Sir Isaac Newton in 1666.

Light of different colors is refracted by different amounts when it passes from one medium (air, for example) into another (water or glass, for example).

There are certain times when you actually see 2 rainbows. Magnificent huh?


However, not all of the energy of the ray escapes the raindrop after it is reflected once. A part of the ray is reflected again and travels along inside the drop to emerge from the drop. The rainbow we normally see is called the primary rainbow; the second rainbow is called the secondary rainbow.

Another interesting fact!

Rainbows are usually present during full moon, at night of course, called the lunar rainbow!

A full moon is bright enough to have its light refracted by raindrops just as is the case for the sun. Moonlight is much fainter, of course, so the lunar rainbow is not nearly as bright as one produced by sunlight.

More about rainbows - click here!

Heat and its Effects

Heat changes the size of a substance.

Heat - substance expands
Cool - Substance contracts

Solids

Examples: Metal ring and ball

Liquids

Examples: Glass flask containing coloured water
- Hot water
   + Liquid level rise
- Cold water
   + Liquid level drop

Gas
Examples: empty flask containg air and a drop of coloured water
- Hot hands/water
   + Coloured waster rises
- Iced water
   + Coloured water dropped

Problems

Problem

- Cause pavements to crack/ tiles pop out
Solution
- Expansion gap

Problem

It's the closest I can get

- Railway tracks wrap
Solution
- Gaps in between tracks

Problem
- Bridges expand, and may be at risk of damage
Solution

- Expansion gaps or resting on rollers

Problem
- Expansion of water pipes/ oil pipelines, causing them to burst
Solution

- Expansion bends

Problem

- Telephone wires/ cable contract in cold weather, and become taut, any may snap
Solution
- Wires are strung loosely

Uses of expansion
Riverts

- Join steel plates and girders

- Bimetallic strip
  + Thermostat
  + Thermometer

Click here for websites more about it.