Sai Science academy

Cell  is the basic fundamental and structural unit of life. All living organisms areade up of one or more cells. Microscope  is an instrument used to see objects which are too small to be seen through our Naked eyes.  Cells  are highly organised and all their functions an regulated. It is not just the rate of cell division that is controlled, but also the rate of cell death. If cells are longer needed, they commit suicide by activating an intracellular death program. This process is called programmed cell death or apoptosis. Robert Hooke  in  1665  observed the slices of cork under a microscope, he coined the name as  cell . Anton Van Leeuwenhook  invented  microscope   Mathias Schleiden proposed that all plants are made up of cells. Cell theory was proposed by Schleiden and Schwann. The main postulates of cell theory are: • All living organisms are composed of one or more cells.  • Cell is the basic unit of structure, function...

Electron flow vs. Conventional Current    In 1752, prior to electricity being identified with the electron, Ben Franklin chose a convention regarding the direction of current flow. Franklin assumed that positive charge carriers flowed from positive to negative terminals. We now know this is incorrect. In metals, the charge carrier is the electron whose charge is negative by definition (note negative sign): (−1.6 × 10−19 C)   The flow of electrons is termed electron current. Electrons flow from the negative terminal to the positive. Conventional current or simply current, behaves as if positive charge carriers cause current f low. Conventional current flows from the positive terminal to the negative. Perhaps the clearest waytothinkaboutthis is to pretend as if movement of positive charge carriers constituted current flow.    It is important to realize that the difference between conventional current flow and electron flow in no way effects any real-world behavior...

 Current is the flow of electrons  SI unit - Amperes (A)  Other units - mA - Milli Amperes  1A= 1000mA 1mA = 1/1000A Electric current (I) = V/R  Electric current= Charge / Time  Electrons are negatively charged they flow from the negative terminal to the positive terminal  But  Conventional current or electric current flows from positive to negative  This is the opposite flow get more about here

 Ohm's Law is used to calculate the relationship between voltage, current and resistance in an electric circuit. Ohm's Law - V= I×R V- Voltage (unit of potential difference) I- Electric current R- Resistance  -> V= IR  -> I=V/R  -> R=V/I  ✓ Resistance  Resistance is the restriction to the flow of electrons    SI unit- Ohm Ω  R=V/I  -> Size  More length - More resistance Less length - Less resistance -> Thickness  Thin - More resistance Thick - Less resistance -> Material  Copper - Less resistance Aluminum - More resistance -> Temperature More temperature - More resistance Less temperature - less resistance 

 Big Bang Theory is most accepted theories of creation of universe, but there are some questions left unanswered from this theory. Some questions are there I will try to answer by a new theory(read this with a fresh and accepting mind)  Before starting see the BIG BANG theory  We all know that if anything or any event or any action happening should happen somewhere at some time at some place. You can take any common action it follows this rule  But According to big bang Universe is begun with a bang, then this neglects the rule, we can assume that big bang happened somewhere, but we don't know where it happened this can be asked as a question  Now what created matter and antimatter, or how was it created For now we know there are matter, antimatter and energy  OK if we assume it was created but In time of big bang what the bubble smaller than atom is created of?  If we ask questions like this then there is no end for questions, to understand something...

 1. Resource is anything obtained from environment to satisfy our needs and wants.  2. A natural resource is one obtained from nature  3. Exhaustible natural resources are those which are present in limited quantity in nature . Eg:- Forests, coal, petroleum, natural gas etc 4. Inexhaustible natural resources are those which are present in unlimited quantity in nature . Eg:- Air, water, sunlight etc 5. Petroleum is also known as Black gold

 2. FRICTION 1. Friction is the force which opposes the relative motion between the two Surfaces in contact and it acts on both the surfaces. 2. Friction depends on the nature of surfaces in contact. 3. Friction is independent of the area of contact. 4. Friction is caused by irregularities on the two surface in contact. 5. 6. Static Friction comes into play to counter balance the applied force on the body. When one surface is sliding over the other sliding friction comes into play. 7. When one body rolls over the surface of another body, the resistance to its motion is called the rolling friction. 8. The sliding friction is slightly less than the static friction. 9. The frictional force exerted by fluid is called drag. 10. Friction can be reduced by using:- grease oil, powder, ball bearing and using anti friction alloy. 11. The substance which reduce friction are called lubricants. 12. Rolling friction is smaller than the sliding friction. 13. The sole of the shoes and the tyres of...

# Speed= Distance/ Time  # Time = Distance/ Speed  # Km/hr to m/s conversion:    X Km/hr = (x × 5/18) m/s  # m/s to km/hr conversion:     X m/s = (x × 18/5) km/hr  # If the ratio of the speeds of A and B is a : b, then the ratio of the time taken by them to cover the same distance is 1/a : 1/b or b : a  # Suppose a man covers a certain distance at x km/hr and an equal distance at y km/hr. Then,the average speed during the whole journey is   (2xy/x+y) km/hr Thank you  Regards SSA Sai Group

 Q1) What is a pixel? Ans- Pixel is a small dots or squares that make up a image or a screen Many pixels make a screen, every screen has many pixels. Q2) What is HLA typing Ans- HLA typing is a kind of genetic test used to identify certain individual variations in a person's immune system.  This is especially used to find out the type of blood, it is important to know HLA typing, in case of any blood transplant, this is used.  Every people have different HLA typing, so the person with same HLA typing can donate the blood to the person with same HLA typing. So I hope you understand, if you want more information and details on it then tell me in comment's. Q3) What is the purest form of sound? Ans- Beejakshara We hear many different type of sounds, but purest form of sound in beejakshara. Beejakshara is written in hindu texts as OM, shreem, hreem..... Etc. These sounds when you spell then some vibrations starts inside and you start to go into some super meditation.  No...

 Q1) What is a Black hole Ans- A Black is a region of space time where gravity is intense  Q2) How is a Black hole formed  Ans- a Black hole is formed when a massive star explodes, this process is called supernova, in this way a Black hole is formed. Did you know! Our can't form a Black hole because it is not too massive, thus when Sun explodes it is not called as supernova Q3) Where are the black holes present? Ans- The supermassive Black hole lie at the center of the Galaxies. Did you know! The name of the black hole present at center of MILKY WAY GALAXY is SAGITTARIUS A  Q4) Why black holes so intense Gravity  Ans- The gravity is so strong because matter has been squeezed into a tiny space. Did you know! The gravity in black holes are so strong that even light can escape. Hi viewers This is SSA from Learn it, Sai group, I try to spread information through my blogs and websites. Our motto of this group is Information should be free. I will reach u with a lot ...

 There is a Black hole at the centre of the galaxy At center of MILKY WAY GALAXY a Black hole named SAGITTARIUS A  SAGITTARIUS A- Sagittarius A is a bright and very compact astronomical radio source at the Galactic Center of the Milky Way. It is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of the ecliptic, visually close to the Butterfly Cluster and Shaula. Distance to Earth: 25,640 light years Radius: 22 million km Discovered: 13 February 1974 Coordinates: RA 17h 45m 40s | Dec -29° 0′ 28″ Constellation: Sagittarius Discoverers: Reinhard Genzel, Andrea M. Ghez, Harry Clive Minnett, Robert Brown, Bruce Balick  So for a galaxy there is a Black hole at the center  Hi viewers This is SSA from Learn it, Sai group, I try to spread information through my blogs and websites. Our motto of this group is Information should be free. I will reach u with a lot of topics covered. Visit my blogs and stay tuned  Follow my blog  ...

 Welcome to SSA From learn it  Charge - Charge is the property of matter that produces ans experiences electrical and magnetic effects   Point charge:- when linear size of charged body is much smaller than the distance under consideration, the size may be ignored and the charges body is called point charge.  Electrification - The process of giving charge to a body is called electrification. Methods of electrification  a) Charging by friction Two glass rods rubbed with silk or wool cloth are brought close to each other, they repel each other  The two strands of wool or two pieces of silk cloth, with which rods were rubbed, also repel each other. However, the glass rod and wool attracted each other. Similarly, two plastic rods rubbed with cat's fur repelled each other but attracted the fur. On the other hand, the plastic rod attracts the glass rod and repel the silk or wool with which the glass rod is rubbed. The glass rod repels the fur. In this process whe...

 Q1) Light   a ray or a wave or a particle Ans- In first of classes light is taught to us as a ray and it travels in a straight line  But then after in further classes its told light is a wave   Then again in higher classes it is told light is a particle Now we will get confused that is light a ray or a wave or a particle  Light is a particle called photon,  It is also a electromagnetic wave, a transverse wave Q2) How light travels in higest speed? Ans- Light is made of a particle called photon. Photon  is a massless particle, that means it has no mass, now we know that if a particle has no mass then there will be no resistance force (i.e. Friction, gravity) nothing will stop this Photon, so that's the reason light travels very fast. Hi viewers This is SSA from Learn it, Sai group, I try to spread information through my blogs and websites. Our motto of this group is Information should be free. I will reach u with a lot of topics covered. Visit my...

 Welcome to SSA  Q1) Can we hear in space Ans-Sound needs a medium to travel, space is almost vaccum, so sounds can't travel in space, so we can't hear any sound  Did you know!  If sound travels through space then sounds from Sun can reach earth and it can cause worst effects on human hearing, because on Sun a lot of volcanic activities happening every minute, now we can image the sound of volcano eruptions travelling to earth then none of the humans can hear as every time there is unnecessary sound  Q2) How do aeroplanes fly  Ans- Aeroplanes work in a principle called lift it is about pressure difference, now I will tell what's lift When an aeroplane starts to run on runway then the air above the wings blow off , this creates a low pressure region above the wing and a high pressure at bottom, so due this pressure differences aeroplanes lift off, this maintains the balance of aeroplanes Did you know! Aeroplanes change their direction through a pane at the b...