Kinetic Particle Theory, Brownian motion and Diffusion + Inertia

The kinetic model of matter states that all matter is made up of a large number of tiny particles called atoms or molecules that are in continuous random motion.
States of matter (using the kinetic model of matter )

Solid
Arrangement of particles > Closely packed in an orderly arrangement
Motion of particles > Vibrate about fixed positions
Space between particles > Very little
Forces between particles > Very strong attractive forces

Liquid
Arrangement of particles > Loosely packed in an disordered arrangement
Motion of particles > Slip, slide and roll about one another
Space between particles > Little
Forces between particles > Strong attractive particles

Gas
Arrangement of particles > Very far apart in a random arrangement
Motion of particles > Move freely and randomly at high speeds in all directions
Space between particles > Very large
Forces between particles > Weak and negligible attractive forces

Brownian motion

Brownian motion is the random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the quick atoms or molecules in the gas or liquid.

The Roman Lucretius's scientific poem "On the Nature of Things" (c. 60 BC) has a remarkable description of Brownian motion of dust particles. He uses this as a proof of the existence of atoms:

"Observe what happens when sunbeams are admitted into a building and shed light on its shadowy places. You will see a multitude of tiny particles mingling in a multitude of ways... their dancing is an actual indication of underlying movements of matter that are hidden from our sight... It originates with the atoms which move of themselves [i.e., spontaneously]. Then those small compound bodies that are least removed from the impetus of the atoms are set in motion by the impact of their invisible blows and in turn cannon against slightly larger bodies. So the movement mounts up from the atoms and gradually emerges to the level of our senses, so that those bodies are in motion that we see in sunbeams, moved by blows that remain invisible."

To find out more about the Brownian motion, click here
Here is a stimulation of the Brownian motion i found on Google.

Diffusion
Diffusion is the net movement of a substance (e.g., an atom, ion or molecule) from a region of high concentration to a region of low concentration. This is also referred to as the movement of a substance down a concentration gradient. A gradient is the change in the value of a quantity (e.g., concentration, pressure, temperature) with the change in another variable (e.g., distance). For example, a change in concentration over a distance is called a concentration gradient, a change in pressure over a distance is called a pressure gradient, and a change in temperature over a distance is a called a temperature gradient. 
To find out more on diffusion, click here
Here is a picture of Diffusion i found on Google

Inertia

Inertia is the resistance of any physical object to any change in its state of motion, including changes to its speed and direction. It is the tendency of objects to keep moving in a straight line at constant velocity. The principle of inertia is one of the fundamental principles of classical physics that are used to describe the motion of objects and how they are affected by applied forces. Inertia comes from the Latin word, iners, meaning idle, sluggish. Inertia is one of the primary manifestations of mass, which is a quantitative property of physical systems.Isaac Newton defined inertia as his first law in his Philosophiæ Naturalis Principia Mathematica, which states:

The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.

In common usage the term "inertia" may refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), or sometimes to its momentum, depending on the context. The term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his First Law of Motion: that an object not subject to any net external force moves at a constant velocity. Thus, an object will continue moving at its current velocity until some force causes its speed or direction to change.

On the surface of the Earth inertia is often masked by the effects of friction and air resistance, both of which tend to decrease the speed of moving objects (commonly to the point of rest), and gravity. This misled classical theorists such as Aristotle, who believed that objects would move only as long as force was applied to them.

To find out more on inertia, click here

Here is a video on Youtube about inertia. Enjoy!

Thank you for reading!

Classification of matter

Matter exist in 3 physical states: Solid, liquid and gas. However, did you know that matter can exist in 2 other physical states? Incredible! This 2 states are Plasma and Bose-Einstein Condensate.

Plasma

Plasma is loosely described as an electrically neutral medium of positive and negative particles (i.e. the overall charge of a plasma is roughly zero). It is important to note that although they are unbound, these particles are not ‘free’. When the charges move they generate electrical currents with magnetic fields, and as a result, they are affected by each other’s fields. This governs their collective behavior with many degrees of freedom.

Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). When air or gas is ionized, plasma forms with similar conductive properties to that of metals. Plasma is the most abundant form of matter in the Universe, because most stars are in a plasma state.

Plasma comprises the major state of matter of the Sun. Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions. Ionization can be induced by other means, such as strong electromagnetic field applied with a laser or microwave generator, and is accompanied by the dissociation of molecular bonds, if present. Plasma can also be created by the application of an electric field on a gas, where the underlying process is the Townsend avalanche.

The presence of a non-negligible number of charge carriers makes the plasma electrically conductive so that it responds strongly to electromagnetic fields. Plasma, therefore, has properties quite unlike those of solids, liquids, or gases and is considered a distinct state of matter. Like gas, plasma does not have a definite shape or a definite volume unless enclosed in a container; unlike gas, under the influence of a magnetic field, it may form structures such as filaments, beams and double layers. Some common plasmas are found in stars and neon signs. In the universe, plasma is the most common state of matter for ordinary matter, most of which is in the rarefied intergalactic plasma (particularly intracluster medium) and in stars. Much of the understanding of plasmas has come from the pursuit of controlled nuclear fusion and fusion power, for which plasma physics provides the scientific basis.

Click here to find out more about Plasma.

Here is a video found on Youtube about plasma.

Bose-Einstein Condensate

A Bose–Einstein condensate (BEC) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero (that is, very near 0 K or −273.15 °C^[1]). Under such conditions, a large fraction of the bosons occupy the lowest quantum state, at which point quantum effects become apparent on a macroscopic scale. These effects are called macroscopic quantum phenomena.

Click here to find out more about the Bose-Einstein Condensate

Here is a video on Youtube about the Bose-Einstein Condensate

Thank you for reading! I hope your mind was blown!

Elements, Compounds and Mixtures

Elements, compounds and mixtures are some categories that refer to the composition of a substance. The properties of substances allow scientists to identify a given substance as an element, compound or mixture.

Elements
An element is a substance that cannot be further broken down using chemical reactions to give simpler substances. For example, when common salt is heated and then electrically decomposed, it gives sodium and chlorine which cannot be further broken down into simpler substances. Hence, common salt is a compound while sodium and chlorine are elements.
An element has both a name and a symbol for it to be represented in the periodic table. For instance, an element may be named "hydrogen" and designated the symbol "H".
Here is the picture of a periodic table and a song from AsapSCIENCE. Enjoy!





 

 

An element is either made up of atoms or molecules. A molecule is a group of two or more atoms chemically joined together.

 

So, how do you classify elements?

 

1. Classification by state.

Elements can be classified according to their physical state at room temperature and pressure.

2. Classification as metals/metalloids/non-metals

Elements can also be classified by their metallic properties. Elements that are good conductors of electricity would be classified under metals while elements that are poor conductors of electricity would be classified under non-metals. However, there are some elements that have both metallic and non-metallic properties, which are classified under metalloids.

3. Periodic table classification

Elements belonging to the same column, or group, (vertical) have similar chemical properties while elements in the same row, or period, (horizontal) show a gradual decrease in non-metallic properties.

 

Compounds

A compound is a substance containing 2 or more elements chemically joined together. It can be decomposed to give 2 or more simpler substances. A compound is formed through chemical reaction between different elements. Usually, compounds can be broken back down into their constituent elements by using electricity or heat.

 

Mixtures

A mixture comprises 2 or more substances that are not bonded together through chemical means. It can comprise of elements, compounds or both, and these may be solids, liquids or gases.

 

Differences between a compound and a mixture

1. A compound's melting and boiling points are fixed, while a mixture melts and boils over different temperatures.

2. A compound requires chemical reactions to be separated into its constituent elements while a mixture may be easily separated into its components using physical means.

 

Periodic table

The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers, electron configurations (electron shell model), and recurring chemical properties. Elements are presented in order of increasing atomic number (the number of protons in the nucleus). The standard form of the table consists of a grid of elements laid out in 18 columns and 7 rows, with a double row of elements below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that.
The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences.
In the standard periodic table, the elements are listed in order of increasing atomic number (the number of protons in the nucleus of an atom). A new row (period) is started when a new electron shell has its first electron. Columns (groups) are determined by the electron configuration of the atom; elements with the same number of electrons in a particular subshell fall into the same columns (e.g. oxygen and selenium are in the same column because they both have four electrons in the outermost p-subshell). Elements with similar chemical properties generally fall into the same group in the periodic table, although in the f-block, and to some respect in the d-block, the elements in the same period tend to have similar properties, as well. Thus, it is relatively easy to predict the chemical properties of an element if one knows the properties of the elements around it.

The information above is found on Wikipedia

Thank you for reading! The videos above are found on Youtube.

Mass, Weight and Density

Today's blog post is on mass, weight and density. Do not be fooled! Mass is not weight!

MASS
The mass of an object is a fundamental property of the object; a numerical measure of its inertia; a fundamental measure of the amount of matter in the object. Definitions of mass often seem circular because it is such a fundamental quantity that it is hard to define in terms of something else. All mechanical quantities can be defined in terms of mass, length, and time. The usual symbol for mass is m and its SI unit is the kilogram. While the mass is normally considered to be an unchanging property of an object, at speeds approaching the speed of light one must consider the increase in the relativistic mass.
The weight of an object is the force of gravity on the object and may be defined as the mass times the acceleration of gravity, w = mg. Since the weight is a force, its SI unit is the newton. Density is mass/volume.

 

WEIGHT

The weight of an object is defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity, w = mg. Since the weight is a force, its SI unit is the newton.For an object in free fall, so that gravity is the only force acting on it, then the expression for weight follows from Newton's second law.
You might well ask, as many do, "Why do you multiply the mass times the freefall acceleration of gravity when the mass is sitting at rest on the table?". The value of g allows you to determine the net gravity force if it were in freefall, and that net gravity force is the weight. Another approach is to consider "g" to be the measure of the intensity of the gravity field in Newtons/kg at your location. You can view the weight as a measure of the mass in kg times the intensity of the gravity field, 9.8 Newtons/kg under standard conditions.
Data can be entered into any of the boxes below. Then click outside the box to update the other quantities.
At the Earth's surface, where g=9.8 m/s² :

The weight of mass kg is Newtons
The weight of mass slugs is pounds

All the information above can be found here>HyperPhysics

DENSITY
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ (the lower case Greek letter rho). Mathematically, density is defined as mass divided by volume:

If you want to find the volume of something, just divide mass by the density of it.
If you want to find the mass of an object, just multiply its volume by its density.

Thank you for reading! References from Wikipedia.

Here is an interesting video from AsapSCIENCE

Measurements

Imagine trying to measure the inner diameter of a circular cylinder. How are you going to do that? Put a ruler in between? That would not be feasible as a ruler would not be able to fit in. What if we want to measure something that rulers are not able to measure? What do we do? Today's blog post is about measurements and I am going to show you 2 wonderful apparatus for measurements. They are the Vernier Caliper and the Micrometer Screw Gauge.

Firstly, let me talk about the Vernier Caliper.
"The main use of the vernier caliper is to measure the internal and the external diameters of an object." Here is a picture of a Vernier Caliper.

 

Here are the parts of the Vernier Caliper and their functions.

 

1. Outer Jaws: For measuring the external diameter of objects.

2. Inner Jaws: For measuring the internal diameter of objects.

3. Vernier Scale: "A vernier scale is a device that lets the user measure more precisely than could be done by reading a uniformly-divided straight or circular measurement scale. It is scale that indicates where the measurement lies in between two of the marks on the main scale."

4. Depth Probe: To measure the depths of objects.

 

Here is a video on how to use the Vernier Caliper.

 

 

How a Vernier Scale works.

 

 

"The vernier scale is constructed so that it is spaced at a constant fraction of the fixed main scale. So for a decimal measuring device each mark on the vernier is spaced nine tenths of those on the main scale. If you put the two scales together with zero points aligned, the first mark on the vernier scale is one tenth short of the first main scale mark, the second two tenths short, and so on up to the ninth mark—which is misaligned by nine tenths. Only when a full ten marks are counted is there alignment, because the tenth mark is ten tenths—a whole main scale unit short, and therefore aligns with the ninth mark on the main scale."

 

 

A typical Vernier Caliper can measure 0.1mm readings and has a typical maximum accuracy of  +0.05mm.

 

 

Now I will be introducing you to a far more complex instrument that has a maximum accuracy of +0.005mm! It is the Micrometer Screw Gauge.

 

"A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are usually, but not always, in the form of calipers (opposing ends joined by a frame), which is why micrometer caliper is another common name. The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil. The spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil."

 

Here are 2 pictures of the Micrometer Screw Gauge.

 



Here is a video on how to use the Micrometer Screw Gauge. Enjoy!

 

Here are the parts of the Micrometer Screw Gauge as found on Wikipedia.

 

Frame

The C-shaped body that holds the anvil and barrel in constant relation to each other. It is thick because it needs to minimize flexion, expansion, and contraction, which would distort the measurement.
The frame is heavy and consequently has a high thermal mass, to prevent substantial heating up by the holding hand/fingers. It is often covered by insulating plastic plates which further reduce heat transference.
Explanation: if you hold the frame long enough so that it heats up by 10°C, then the increase in length of any 10 cm linear piece of steel is of magnitude 1/100 mm. For micrometers this is their typical accuracy range.
Micrometers typically have a specified temperature at which the measurement is correct (often 20°C [68°F], which is generally considered "room temperature" in a room with HVAC). Toolrooms are generally kept at 20°C [68°F].

Anvil

The shiny part that the spindle moves toward, and that the sample rests against.

Sleeve / barrel / stock

The stationary round part with the linear scale on it. Sometimes vernier markings.

Lock nut / lock-ring / thimble lock

The knurled part (or lever) that one can tighten to hold the spindle stationary, such as when momentarily holding a measurement.

Screw

(not seen) The heart of the micrometer, as explained under "Operating principles". It is inside the barrel. (No wonder that the usual name for the device in German is Messschraube, literally "measuring screw".)

Spindle

The shiny cylindrical part that the thimble causes to move toward the anvil.

Thimble

The part that one's thumb turns. Graduated markings.

Ratchet stop

(not shown in illustration) Device on end of handle that limits applied pressure by slipping at a calibrated torque.

 

As you can see, it is actually quite easy to use this measuring instruments.

 

Now I will be introducing a problem when handling this instruments- Zero Error.

I will start off with Zero Error for the Micrometer Screw Gauge. Here is a picture.

As you can see, when there is no zero error, the zeros on the scales align perfectly. However, Positive zero error occurs when the ‘0’ marking of the thimble scale is below the horizontal reference line of the main scale. Negative zero error occurs when the ‘0’ marking of the thimble scale is below the horizontal reference line of the main scale. When zero errors occur, our results will not be accurate. So how do we solve this problem? It's very simple!

Positive zero error
The error is +x mm. To correct the reading, we subtract the error from the measurement.
Negative zero error
The error is -(0.1-y) mm. To correct the reading, we subtract the error from the measurement.

Now I will continue with zero errors for the vernier caliper.



 

"In a vernier caliper, you can either have a positive zero error or a negative zero error if the zero of the main scale does not coincide with the zero of the vernier scale. If the zero mark is slightly on the right side of the zero on the vernier we have a positive zero error. If it is on the left, then a negative zero error. To get the correct reading, the poistive zero error is subtracted from the final reading and the negative Z.E is added."

 

 

Thank you for reading. References from Google, Wikipedia and Youtube.

Basic Laboratory Orientation

The first time in the school lab was an eye-opener for me. The lab was big and well ventilated and had a wide range of items that were totally alien to me. I learnt about many laboratory apparatus that I had never seen before, such as the pipette and burette. I also learnt about the rules and regulations in the lab and what I must do when an accident occurs.

Here are some examples of what to do when an accident occurs.

1. What should you do if you accidentally spilled some strong acid onto your skin?
Answer: Wash it thoroughly with plenty of water.

2. David poured 30cm^3 of acid into a beaker from a container meant for the entire class. He only used 20cm^3. What should he do with the excess acid?
Answer: He should pour the excess acid into a special bottle meant for disposal as instructed by his teacher. Warning! Do not pour it into the dustbin as it requires special disposal methods and is also dangerous for other lab users.

3. Why is it dangerous to leave a non-luminous flame unattended?
Answer: A non-luminous flame can hardly be seen and may cause others to burn themselves accidentally.

Here is a picture showing you some basic lab apparatus.

 

 

One interesting thing I learnt in the lab is how to light a Bunsen burner.

 

The best way to light a Bunsen burner would be to close the air-hole, turn on the gas tap slowly and ignite a lighter near the mouth of the barrel.

 

Here is the picture of a Bunsen burner with its parts labelled.

Here is a video on how to light a Bunsen burner.

When the air inlet of the Bunsen burner is closed, you get a luminous flame.
When the air inlet of the Bunsen burner is opened, you get a non-luminous flame.

What are the differences between a luminous and non-luminous flame?

Firstly, the flame of the luminous flame is unsteady whereas the flame of the non-luminous flame is steady.

Secondly, the luminous flame can be seen from a distance but the non-luminous flame cannot be seen from a distance.

Thirdly, the luminous flame is not as hot as the non-luminous flame, which means that the non-luminous flame is hotter than the luminous flame.

Why does a "strike-back" occur when the air holes are fully opened?
Answer: When the air-holes are fully opened, a large supply of air enters and the gas burns at the jet instead of the mouth of the barrel, causing a "strike-back".


Thank you for reading!
References from Wikipedia, Google and Youtube.

Graphs

Hi everyone, today I will be making a new post about graphs.

What are the applications of graphs?
"Graphs can be used to model many types of relations and processes in physical, biological, social and information systems. Many practical problems can be represented by graphs.

In computer science, graphs are used to represent networks of communication, data organization, computational devices, the flow of computation, etc. For instance, the link structure of a website can be represented by a directed graph, in which the vertices represent web pages and directed edges represent links from one page to another. A similar approach can be taken to problems in travel, biology, computer chip design, and many other fields."

Personally, I feel that graphs are very effective and useful in a sense that they help to categorise information very neatly for further manipulation.

Basically, we are taught two types of graphs by our Science teacher, Mr Tan. They are the straight line graph and the smooth curve graph. For the straight line graph, we can either simply link the points on the graph together to form a straight line or we can draw a line of best fit. the line of best fit is a line on a graph showing the general direction that a group of points seem to be heading. Here is an example:

 

As you can see, the person is drawing the graph in the direction where all the points seem to be heading. All the points also have to be near to the line and not too far away. The line may pass through some or none of the points. Here is a video showing you how to draw the line of best fit. Enjoy!



 

 

The other type of graph is the smooth curve graph. Drawing a smooth curve graph is relatively easy considered to the line of best fit. You just have to make sure your curve is smooth and connects all the dots together. There is another graph known as the best-fit curve. It is almost the same as the line of best fit just that it is curved. You can use a flexi ruler to help you out. Here is an example of a smooth curve graph:

When we draw graphs, we also have to understand something called the axis.

 

What is an axis?

An axis is a "a fixed reference line for the measurement of coordinates."

There are two types of axes, the horizontal and the vertical. It is known as the x and y axis respectively.

The x axis is the independent variable whereas the y axis is the dependent variable.

"the variable that is thought of as a cause is placed on the horizontal axis, and the variable that is thought of as an effect on the vertical axis".

 

What are variables?

A variable is "a quantity which during a calculation is assumed to vary or be capable of varying in value."

 

What is Interpolation and Extrapolation?

 

INTERPOLATION is a method used to approximate values that are in between points of a graph.

 

EXTRAPOLATION is a method for approximating values that are beyond the range of the data. Data must be extrapolated when values needed are not in the range of the measurements obtained. 

 

 Well, a graph is supposed to show the relationship between variable quantities on the x and y axis. Now you know if you've drawn a good graph!

 

References from Google, Wikipedia and Youtube.

 

Thank you for reading!