You learnt about cell. What do you have learnt? That it is a basic and structural unit of life and they are building blocks of life.
Now its time to learn it in detail. Can you tell me that you first discovered the cell? Don’t know, ok I’ll give you a hint: who first discovered the dead cell? Now its easy to answer, the correct answer is Robert Hooke. According tome you have also thought that answer. Now tell me in which year did he discovered this dead cell. The answer is 1665.
You have heard about the word “microscope” and you have also studied about this but can you tell that how many types of microscopes are there and what is the actual meaning of microscope? Can you tell the meaning from only seeing from the word. If yes then this might be your answer. “Micro” means very small and “scope” means to look or to see. This implies that the word “Microscope” means to see very small things.
I’ve asked that how many microscopes are there. Basically there are two types of microscopes:
- Simple microscope
- Compound microscope
Based on illumination there are 4 types of microscopes:
- Optical microscope – Source of illumination is light
- Electron microscope – Source of illumination is beam of electron whose wavelength is 10,000-1,00,000 times less than light.
- Ultraviolet microscope – Source of illumination is UV rays.
- X-ray microscope – Source of illumination is X-ray.
Discovery of cell– Robert Hooke first discovered the dead cell. He was a Lens Grinder by profession. One day when he was grinding his lenses and making microscopes, one thin slice of cork fell under his microscope and he observed that there were many empty compartment surrounded with cell wall made of cellulose, that is why he named “Cellulae”. He then published a book named “Micrographia” in which he wrote all his findings.
Then comes the revolution in the field of biology many people discovered many things and one of the person named “Anton-Von-Leeuwenhoek” discovered the first living cell. He made all his discoveries with all living organisms. And that is why he was called Father of Microbiology and Father of Microscopy.
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Science is a subject in which we study about the nature of substance, activities of object and the special abilities such as the change of color of chameleon etc.
Do you know in what ways science affect us? Or do you really like science and want you to know more?
We will answer this. You have imagined that if we are not able to take air properly or there is no air or we does not have respiratory system to take breath. You have imagined these thing that if they really does not exist then what would happened to us. If you not imagined then it is the time to imagine and to enter the world of science.
This the only time when you can think about what actually cause glaciers to melt, does in 2012 Earth will end and there will be no life on Earth. You will get answer of this in my next posts.
New updates on Sample papers Page. You can visit now to get the second sample paper of Maths SA-II of class IX with Solutions.
You have solved linear equation with one variable. Now it’s time to learn how to solve the equation with two variables.
Consider the equations below:
x + 2y + 4 = 0 , 3x + 4y = 18 , 5u – 6v = 11
Here you see that there are two variable, i.e. x and y , whose values are unknown. In earlier post I have given one equation, i.e. ax – b = 0 , similarly here is one equation ax + by + c = 0 where a ≠ 0 , b ≠ 0.
Now we will learn how to solve these equation given above:
Let us take this equation 3x + 4y = 18 , to solve this equation you have to use trial and error method. When you do trial and error you get x = 2 and y = 3 . If you do more trial and error method you get many solutions of this, one is that I have give first and another is x = 6 and y = 0 . This shows that linear equations in two variable can have infinite number of solutions.
Algebra is a branch of mathematics in which we use variable for unknown quantity.
Ex: 1) ax = b or ax – b = 0
2) 3x – 9 = 3
when we solve these equation we get : 1) x = b/a and in 2) x = 4 . This means the value of x in both these equations are different and can have any value, it is not fixed.
You may have thought that from where this word ‘Algebra‘ came. This word came from the book Kitab al-muhtasar fi Hisab Aljaber w’al muqabalah written by Mohammed ibn Musa abu Abdullah al Khowarizmi of Baghdad around 825 A.D., but much before this , Aryabhatta and Brahmagupta had already done a lot of work in this field.
As I have told you maths is used in many place even in banks and this maths is known as Commerce or Commercial Maths. If you had taken loan then you had noticed that they give you a time periods of 1, 1.5 or 3 years. If you had taken loan of 50,000 for 3 years at the rate of 15% p.a. then the simple interest would be as follows:
S.I. = (50,000 * 15 * 3) / 100
= Rs. 22,500
So, till now you have understood that the formula is S.I. = ( P * R * T ) / 100
Another method is that to find the amount and then subtracting it with the principal, this gives you Compound interest.
Ex: On the same information given above the compound will be:
( Remember the time interval changes when the rate is compounded half yearly and annually.)
Amount = Principal * ( 1 + 15/100 ) * ( 1 + 15/100 ) * ( 1 + 15/100 )
A = 50,000 * ( 1 + 15/100 ) * ( 1 + 15/100 ) * ( 1 + 15/100 )
Therefore, A = 76043.75
C.I = A – P
= 76,043.75 – 50,000
= Rs. 26,043.75
This shows that C.I. and S.I. different when calculated. If the time span is same then the Interests would be same.