An object of height 10 cm is placed 30 infront of convex lens of focal length 20 cm. Use scale drawing to find position, size and nature of the image and Magnification.
solution
we use the scale of 1cm to represent 10cm horizontally and 1cm to represent 10cm vertically. The object is represented by an upright arrow that is placed 30cm on the principal axis from the line that represents the lens.
object distance = 30cm
image distance =60cm
height of image =20cm
height of object=10cm
The image is magnified as it is bigger than the object.
The image is position at 60cm which is beyond 2F on the other side of the lens. It is a real image
Magnification M = (Image distance/object distance) = 60cm/30cm = 2
Heat is a form of energy that flows as a result of temperature difference between two points or region where it passes from a body at higher temperature to the body at lower temperature.
Heat can also be defined as the energy that flows from places of high temperature to places with low temperature.
A body that receives heat has it’s temperature being increased and a body that looses heat has it’s temperature lowered.
If two bodies are at different temperature in the same environment, heat flows from the body at high temperature to body at low temperature until the two bodies are at the same same temperature which is usually a temperature that is between the two initial temperatures. The two bodies are then said to be in thermal equilibrium.
The SI unit for heat is joule(J).
There is no instrument to measure heat directly but when we see a body rising in temperature, we know it has absorbed heat. However, we will expound more on how to measure heat in future lessons.
Heat flow is responsible for the presence of wind in our environment.
What is temperature?
Temperature is the quantity that measures degree of hotness or coldness of a place or an object.
When we talk about degree of hotness, we talks about the feeling. Not a very good way of describing a scientific phenomena. But a more technical definition of temperature is that temperature is the quantity that describes the average energy of particles in a material.
A large heat can cause very little rise in temperature of a substance but also small absorption of heat can cause large increase of temperature. So heat is usually described as the total amount of energy that flows from a body at high temperature to a body at lower temperature.
The temperature change caused by a given heat on a substance depends on the mass of the object and the internal molecular structure of the substance, which is usually known as the heat capacity of the substance.
Heat is measured in joules( the unit for energy) but temperature is measured in Kelvin.
Temperature is a basic physical quantity whereas heat is a derived quantity.
Modes of heat transfer
The common methods by which heat traves from one point to another includes:
Conduction
Convection
Radiation
Conduction
Heat conduction is a process where molecules that are close to the source of heat picks up the heat, vibrates faster and passes on the excess heat to their immediate neighbouring molecules.
The neighboring molecules upon receiving energy from their neighbors increases their vibrations but with with a slower later than the molecules that gave the the energy since they got just a small part of the supplied energy. Therefore, temperature reduces along the material as one moves away from the source.
Convection
Convection is the transfer of heat by the actual movements of the molecules where molecules that receives heat becomes lighter and moves up to allow colder molecules to come to regions of heat.
Convection is the most important means by which heat is transferred in liquids and gases.
Convection can be described as the continuous flow of liquid and gas particles in a complete loop due to a difference in temperature.
Radiation
It is a method of heat transfer by means of electromagnetic radiation.
Electromagnetic radiation are waves that does not need material medium to transfer.
Electromagnetic waves moves the same way, heat from the sun reaches the earth service as it travels without aid of any medium.
Mass is the quantity of matter in a substance. Matter is anything that occupies space.
The mass of an object depends on it’s size and the number of particles it contains.
The SI unit of mass is the Kilogram (Kg).
A kilogram is the mass of a piece of platinum-iridium metal kept at Sevres, near Paris,France at the International Office of Weights and measurements. That piece of metal kept in France is the standard with which all masses of the world are measured with the kilogram unit.
though kilogram is the SI unit, the most common unit of measuring mass is the gram.
The following table shows sub-units of gram and kilogram
Prefix
number of grams (g)
Kilogram (Kg)
1000 g
Hectogram (Hg)
100 g
Decagram (Dg)
10 g
decigram (dg)
(1/10) g
centigram (cg)
(1/100) g
milligram (mg)
(1/1000) g
microgram (µg)
(1/1000,000) g
nanogram (ng)
(1/100,000,000) g
picogram (pg)
(1/1000,000,000,000) g
tables of conversion of grams
1 kg = 1000 tonnes
other units used to measure mass includes:
1 pound (lb) = 0.4536 kg)
1 ounce(oz) = 0.02835kg
Though different weights are experienced depending on gravitational pull of a place, the mass of an object remains constant beacuse number of particles in an object will not change with change of location.
Instruments used to measure mass
Platform balance
Electronic balance
The object whose mass is to be measured is placed on the pan and its weight causes electronic circuit to develop current to display the mass on the digital display. It is a very accurate instrument and is useful in laboratories especially small masses.
Beam balance
works by the principles of moments.
The object whose mass is to be measured is balanced against a known standard mass on as equal arm lever. The beam balances when the mass of the object is equal to the standard mass.
Table balance
works under principles of moments
Spring balances
uses laws of gravitational pull
postal balance
Roman Steelyard Balance
Exercise
convert the following as instructed
1500 tonnes to kg
200000000000 mg into Kg.
256 g into tonnes
0.000000000000000000 567 tonne into pg
12.43 g into mg
Problems involving mass
Sheila went to the grocery store and bought a 3 watermelons that weighed 4.4 kilograms and a bunch of bananas that weighed 750 grams. She also bought a bottle of juice that contained 1.2 liters.
a) Convert the weight of the watermelon from kilograms to grams.
b) If Sarah bought 3 bottles of juice, how many grams of juice did she buy in total if density of juice is 1.25gcm-3?
c) If each banana weighs 125 grams, how many bananas did Sarah buy?
Images formed by lenses has different features based on where the object is positioned with respect to the lens.
There are different region along the principal axis where object can be positioned and each region will determine kind of image obtained.
The regions considered includes:
Beyond Center of curvature C
Object exactly at C
Object between C and F
Object exactly at F
Object between F and the optical center of the lense
Object at infinity
We will now consider each of the positions and examine the kind of images formed.
Object at infinity
Object at infinity is object that is at large distance in respect to the focal length of the lens.
When you focus a distance object, there is that distance between the screen and the lens where the sharp clear image is formed, the distance between the screen and the lens is the focal length and the point where the image is formed is the principal focus of the lens. See the diagram below.
A photo showing image formed for trees some distance from the laboratory
when you focus on distance object such that a sharp image is formed on a white screen as in figure above, then the distance between the screen and the lens is the approximate focal length for the lens.
The rays diagram for the convex lens focusing distance object is shown.
The figure below shows two rays from infinity coming from opposite sides of the principal axis.
The characteristics of image formed when object is at infinity.
Real (formed on the screen)
Inverted
Diminished (smaller than worship
Formed at F
The setup of lenses is used in the objective lens of a telescope.
Object beyond 2F
The characteristics of image formed is
Real
Inverted
Diminished
Formed between F and C on the side of the lens
Object beyond C is a useful setup for cameras and in human eyes
Object at 2F
The figure below shows the image formed by concave lens when an object is exactly at 2F, that is, image at center of curvature of the lens.
The characteristics of images formed includes:
Real
Inverted( upside down)
Same size as the object
Formed at F on the opposite side of the lens
Object at F is a useful setup in terrestrial telescope
Object between F and 2F
It is the only position we have a magnified real image . The image formation is as shown in figure below.
image formation when object is between 2F and F
The characteristics of images formed is:
Real
inverted( upside down)
Magnified (bigger than object)
Formed beyond 2F on the other side of the lens.
Object between F and 2F is a useful setup for microscope objective and photographic enlarger.
Object at F
When object is placed at F, The image formation is as shown in the diagram below
concave image formation for an object at F
The rays emerge parallel after refraction by the lens and is formed at infinity.
A good example of rays of light moving to infinity is rays of light coming from a spotlight, Therefore the object at infinity setup is common in searchlight and spotlights.
Object between F and the lens p
when object is between F and the lens, the rays of light don’t converge but diverge, but if extended backwards, they seems to meet behind the object.
The between F and lens is the only position where the convex lens produces virtual and upright image. The figure below shows image formed when object is between F and the lens
The characteristics of image formed is
virtual
erect
magnified
on the same side as object
Object between F and P is useful in magnifying glasses and the microscope.
Image formed by Diverging lenses
Unlike Convex lens, the image formation by concave lenses does not depend on position of the object but it is always virtual, erect and diminished and the image is always formed on the same side as the object.
The figure below shows formation of an image by concave lens when the object is between 2F and F.
The following shows an image for concave lens when an object is between F and the lens.
conclusion
Images formed by concave lenses depends on the position of the object but. The image by concave lenses are virtual only when it is between F and the lenses.
The image by concave lens does not depend on position of the image. Regardless of the position of the object from the lens, the image is always virtual, diminished and upright.
In books, we use ray diagrams to represent images formed by thin lenses. Ray diagrams are straight lines with arrows that shows direction of light rays.
Points to note when drawing ray diagrams
Real rays and real images are drawn using solid lines
virtual rays and virtual images are drawn in broken lines
To locate the image, two of the three important rays are drawn from the tip of the object towards the lens. The first ray parallel to principal axis and through principal focus, the second ray from the tip of the object through the optical center or the third that passes through the principal focus before moving parallel to the principal axis.
Where two or more rays intersect after refraction by the lenses is the tip of the image.
if the object stands and is perpendicular to the principal axis, the image is also perpendicular to the principal axis.
To complete the image, a line is drawn perpendicular to the principal axis from the tip of the image
If the foot of the object crosses the principal axis, two of the three rays used to locate image should be drawn for both the tip and the foot of the object. A point object for the image tip should be joined with point image of the foot to get the desired image.
converging lenses are represented by the following diagram in drawings:
symbol used for convex lens
concave lenses is usually represented in the diagrams by the picture below.
symbol for concave lens
Example problem
An object 15cm tall has been placed 32cm from a concave lens of focal length 20 cm. By scale drawing, determine:
(a) The position of the image formed
(b) Magnification of the image
(c) The height of the image
solution
We use the scale of 1 cm to represent 5 cm and using two rays to form an image, the resultant image after reflection is as shown
(a) From the diagram, one can see that the image is formed 52cm from the lense.
(b) From the diagram, the height of the image from the principal axis is 24 cm.
substituting for the values of hi and ho, we have:
The same result could be obtained by finding ration of image distance to object distance with some slight variation that comes with measurement errors:
(c ) From the scale diagram, the height of the image is about 24.5cm
Remarks:
The diagram can aslo be used to give further insights about the image formed. For example we can see it is upside down, it is formed by two rays actually meeting, hence the image is real.
Also the image is taller than the object, hence it is magnified just by looking
An image is formed when two or more rays meet at a point. In actual sense, millions of rays meet for an image to be formed. When rays meet and forms an image, the image formed is refered to as a real image.
When determining images formed by a lens, we consider a ray from a point object. Appoint object is a tiny point from the object.
Image formation works just the way eyes work. For you to see any object, rays of light must fall onto the object and then be reflected into your eyes, so that your eyes can form the image about the object on the retina.
The rays must converge after passing through the eye lens for the image to be formed on the retina. Similarly, thin convex lenses converges the rays that fall on it to form an image of the object. The rays of light falls on the object before they are reflected towards the lens.
There are three important rays we use to show image formation by lenses.
These rays are:
A ray reflected from an object that moves parallel to the principal axis and is refracted such that it passes through the principal focus or appears to emerge from the principal focus after refraction.
A ray diagram showing a ray of light from distance object that passes through principal focus after refraction
For a diverging lens, the ray will only appear to be coming from the principal focus as shown
A ray parallel to principal axis that appears to come from principal axis after reflection
A ray that passes from the object and towards the optical center of the lens that passes through the lens undeviated.
A ray diagram showing a ray from distance object that passes through the optical center undeviated.a ray passing thought optical center of concave lens undeviated
A ray that passes from the object and passes through the principal focus and that will move parallel to the principal axis after it it is being refracted.
A ray reflected from an object and passes through principal focus before being refracted by the lens so that it moves parallel to the principal axis.a ray that seems to pass through the principal focus after being refracted to be parallel to principal axis by a concave lens
Meeting of any two rays out the three mentioned will be sufficient to represent an image on a diagram.
The diagram below shows the three rays meeting at a point to form an image of the object
We usually use an upright arrow to represent an object.
for a concave lens, the image formation is imagined by the eye as illustrated below.
Conclusion
image formation needs at least two rays to meet.
Three rays are common is identifying an image.
Image formation by concave lenses is very different from that of concave lens.
Next lesson we will discuss image formation by concave lens.
Thin lenses have their own vocabulary mostly that describes various parts of the lens. This parts includes:
Center of curvature C
Radius of curvature R
Principal axis P
optical center O
Principle Focus F
Focal Length f
Focal plane
We will discuss all the highlighted parts in this lesson
Center of Curvature C
It is defined as the center of the sphere of which the surface of the lens is part.
We consider the lens to have been cut off from a transparent sphere of radius R. In other word, the lens is part of a curved surface of a certain sphere as illustrated below.
For bi-convex lens, the lens is considered to come from two pieces cut from two different spheres and combined at the inner side. Consider the illustration below where we extract service1 and service2 from two spheres.
sphere for surface1
sphere for surface2
Because the bi-convex comes from two spheres, it will have two centers of curvature which will be opposite to each other.
similarly the bi-concave lens is derived from two spheres as illustrated.
Different parts from spheres will be joined two have a concave lens that has two centers of curvature as shown below
Radius of curvature
It can be defined as the radius of the sphere from which the surface of the lens is part.
It can also be defined as the distance between the Center of curvature and the optical center o of the lens.
Principal axis
It is an imaginary line passing through the centers of curvature and is perpendicular to the plane of the lens.
Optical center
It is the geometric center of the lenses where a ray incident to the lens passes on undeviated.
Principal focus
Sometimes also referred to as the focal point. It is a point on the principal axis where rays parallel and close to the principal axis converge after refraction by a convex lens or where the rays parallel and close to the principal axis seems to diverge from after refraction by a concave lens.
The figure below illustrates convergence of parallel rays of light at principal focus after refraction.
showing a principal focus of a convex lens
The virtual principal focus of a concave lens is as illustrated below
A lens has two principal foci, and they are on either side of the lens.
The principal focus of converging lens is said to be real because their actual meeting of rays of light there.
The principal axis of diverging lens is said to be virtual (imaginary) because rays of light do not actually meet there.
Rays that are parallel and close to the principal axis or almost parallel to the principal axis are referred to us paraxial rays.
Rays parallel but far from the principal axis are referred to as marginal rays or axial rays.
Focal length f
It is the distance between the optical center of the lens and it’s principal focus.
By Convection, focal length of converging lens is considered real while that of diverging is considered virtual.
Focal plane
It is an imaginary plane that passes through the focal point and is perpendicular to the principal axis.
Focal plane is illustrated below
rays of light that are not parallel to the principal axis converges at a point on a focal plane or will appear to diverge from there after refraction
Conclusion
In this lesson we have seen that lens are pictured as being extracted from a sphere and the radius of the said sphere plays and important role in description of the lens. A lens converge or diverges rays parallel to the principal axis at the focal point.
A lens can be defined as a piece of curved glass or plastic that makes things look larger, smaller or clearer when you look through it.
In human eye, one component is a lens and so we can also define lens as the transparent part of the eye, behind the pupil, that focuses light so that you can see clearly.
The idea behind lens operations is that when a light ray passes from air which is more optically denser than the lens material, it is refracted.
When many rays passes through the lens, they all refracted the same way and so they meet at a common point. Sometimes they don’t meet but instead they are scattered after refraction but they are seemed to be spreading from a common point.
Lenses are usually made of glass, transparent plastic or perspex.
common application of lenses includes cameras, spectacles,telescopes, microscopes, film projectors and the human eye.
A thin lens means a lens whose thickness is negligible compared to the radius of curvature of the lens surfaces.
Types of lenses
The basic two types of lenses are convex and concave lenses.
Convex lenses are also called converging lenses as they cause the rays that passes through it to meet at a point. Convex lenses are thickest at the middle and they thin in as you move towards their edge.
In this lesson we will be talking about biconvex lenses meaning that it is symmetrical if we cut it long it’s edges. Both sides of it’s services at the center are bulging outwards and the edges are curved inwards uniformly on both sides.see the figure below
Bi convex lens
showing symmetrical in bi-convex lens
Concave lenses are also called diverging lenses as they cause the rays passing through them to be spreading from a common pint. Concave lenses are thinnest at the middle and they they become thicker as you move towards the edges.
Illustrating concave lens
illustrating bi-concave lens
There are variations of convex and concave lenses as illustrated in figures below
plano convex lens
convex meniscus lens
plano concave lens
concave meniscus lens
Effects of lenses on Parallel rays of light
A cardboard with parallel slits is placed between the mirror and a bi-convex lens as in figure below
The mirror is set such that it reflects the sun rays so that the rays passes through the slits before they reach the lens.
After making observations, the bi-convex lens is replaced with a concave lens
Observation
when a convex lens is used, the rays are converged at a point on the paper and then diverge as they continue as shown.
illustrations of parallel rays as they pass through a bi-convex lens
When concave lens is used , the rays diverge as if they were from the focal point in front of the lens as shown.
illustrations of parallel rays as they pass through a biconcave lens
Investigating convergence and divergence of light using a ray box
A ray box acts as a source of parallel beam. A spot light can also be used.
A parallel beam is directed incident to the the lens as shown
Parallel rays of light incident to a convex lens
A white paper is placed on the other side of the lens and it’s position adjusted until a sharp point is observed.
observation
When a convex lens is used, the rays are converged at a point on the paper and then diverges as they continue as shown below
Parallel beam after passing through a converging lens
If convex lens was replaced with concave (diverging) lens, the rays will be observed diverging as if they are coming from a point on the other side of the lens. see the diagram below.
Parallel beam incident to diverging lens
Explanations
Light is usually refracted when it passes through a glass prism. A lens can be considered as an assembly of many tiny prisms where each prism refracts light as in figure below.
Illustrations of bi-convex lens as an assembly of prisms
Please note that, the middle part of the prism is like a rectangular glass prism and a ray that is incident to it at a perpendicular angle passes through without being refracted. As we may see in other lessons, a ray of light that passes normally through the geometrical center of the lens, passes through undeviated.
The figure below shows representation of concave lens as an assembly of prisms.
illustrations of concave lens as an assembly of prisms
conclusions
Rays of light that passes through a lens converges at a fixed point from the lens if the lens is a converging lens or diverge from a common imaginary point if the lens is a diverging lens.
The point at which the rays emerging from the lens converge or seems to diverge from is referred to as the principal focus.
A convex lens has a real principal focus while a concave lens has a virtual (imaginary) principal focus.
Volume of irregular solids are measured using the displacement method.
A solid whose volume is needed must NOT be soluble in water because the method involves immersing the object in water. Similarly, the object should NOT be able to absorb water nor react with water.
displace methods can be used in two different ways:
Using Measuring cylinder
Using a Eureka can
Using a measuring cylinder
The basic principle behind this method is like that of the Archimedes’s principle because the volume of water displaced by the solid in the measuring cylinder is the actual volume of the solid.
Some water is placed in a measuring cylinder and it’s volume which we call V1 is read and recorded as from the diagram below.
reading of water level before immersing the solid
After the volume is read, the solid is tied on a string and slowly lowered into the measuring cylinder. The new Volume V2 of the liquid is recorded as in figure below.
Level of water after immersing the stone
The change in volume from V1 to V2 represents the addition of volume added by the solid; hence the volume of the solid will be given by
Vs = V2-V1 where Vs = volume of the stone
Using a Eureka can
A Eureka can (also known as a displacement can) is a container with a spout from the side. Any liquid that is beyond the spout level flows out through the spout. It is also known as an overflow can.
Our stone which represents any solid that whose volume can be measured displaces the water causing it to flow through the spout.
Consider the diagram below.
Eureka can before placing the stone
Before the stone is immersed, you ensure that the water is at the level of the spout exactly. It is an important step because it determines accuracy of your measurements.
You ensure the level is correct by adding some water on the can and then wait until it stops overflowing.You then bring a dry and clean measuring cylinder under the spout before lowering the stone as shown here.
after immersing the stone
After the stone is lowered into the can, the water it displaces flows out of the spout.
The volume read from the collected water in the measuring cylinder is the volume of the stone.
Experiment to determine Volume of an objects that floats on water surface
The idea behind the exercise is to tie a floating object onto the object that sinks into water so that both can sink. It is like increasing the density of the floating object so that it exceeds that of water.
Apparatus:
Eureka can
measuring cylinder
plastic cork
small metal block(sinker)
Procedure:
Fill the Eureka can with water such that you allows excess water to flow through the spout as in figure below.
After water has stopped flowing through the spout, place a measuring cylinder under the spout.
Tie the sinker with a thread and lower it gently into the can as in figure below.
Measure the volume V1 of the water that overflows and is collected into the measuring cylinder.
Remove the sinker and tie it to the cork as shown
Fill the Eureka can again and allow excess water to flow out
When water stops flowing from the spout, place a dry clean measuring cylinder under the spout.
Lower the sinker and the cork tied together gently into the eureka can as illustrated below.
Measure the new volume V2 that is collected into the measuring cylinder.
The water collected in the measuring cylinder is the volume of the sinker and cork combined. If we subtract the volume V1 collected earlier for the sinker alone, we finds the volume of the cork.
Therefore, Volume of the cork Vc = V2-V1
Conclusion
In this lesson, we discussed about finding volume of irregular solids. The method we discussed is called displacement method and it involves immersed the object in water and determining amount of water that is displaced by the object.
Albert Einstein was a Jew born by Jews Parents living German Empire in 19th century And became a theoretical physicist who is considered one of the greatest and most influential scientists of all time.
He is best known for his theory of relativity and development of quantum mechanics.
He was a central figure in reshaping the scientific understanding of nature in modern physics which had been accomplished in the first decades of the twentieth century.
His equation that relates mass with energy, E=mc2 is considered the world’s most famous equation.
Einstein’s Quick facts
Here are few things you may need to know about Albert Einstein.
Real Name: Albert Einstein
Gender: Male
Age: Died at 76 years 0 months 25 days
Birth Date: 14th March 1879
Place of Birth: Ulm, Kingdom of Württemberg, German.
He was born in Ulm in the n the Kingdom of Württemberg in the German Empire, on 14 March 1879 by secular Askenazi Jews.
His father, Hermann Einstein was a salesman and an engineer who had married Einstein’s mother Mrs Pauline Koch,a Jew.
His Family moved to Munich’s borough(District) of Ludwigsvorstadt-Isarvorstadt where his father partnered with his uncle Jakob to establish a company that manufactured D.C electrical equipments.
Albert Einstein was enrolled at Catholic elementary school in Munich in 1884. In 1887, he was transferred to Luitpold-Gymnasium where he received advanced primary and secondary education.
His father’s company failed to secure a contract to install electric lighting in Munich beacuse it lacked a capacity to provide alternating current (A.C) technology which was needed. Consequentially, they sold the company and moved the family to Milan Italy and few months later, they moved to settle at Palazzo Cornazzani in Pavia, in Lombardy, where they lived between 1895 and 1896. Einstein was left at Munich so that he can finish school.
His father wanted him to study electrical Engineering but he was irritable and quarrelsome child that criticized school. He was quoted saying that the school’s policy of strict rote learning could never help in creativity.
At the end of December 1894, a letter from a doctor persuaded the Luitpold’s authorities to release him from its care, and he joined his family in Pavia.
Einstein the genius
Einstein excelled in physics and mathematics from an early age and quickly acquired mathematical skills that could match the ability of students that were several years ahead of him in school.
A family tutor, Max Talmud, expressed frustrations with Einstein beacuse Einstein speed of learning was higher than the teacher could catch up.
By age of fourteen, he had already mastered the concepts of integral and differential calculus. At age of twelve, he confidently claimed that nature could be described as a mathematical structure.
His tutor said that at age of only thirteen, he could understand and enjoy Kant’s Critique of Pure Reason which was usually difficult to understand by common people.
Albert Einstein Education
Albert Einstein sat the entrance examination for the federal polytechnic school in 1895 in Zürich, Switzerland and failed to reach the required standard in the general part of the test though he performed with distinction in physics and mathematics.
He completed his secondary education at the Argovian cantonal school (a gymnasium) in Aarau, Switzerland and graduated in 1896.
He enrolled in the four-year mathematics and physics teaching diploma program at the Federal polytechnic school in 1896.
Einstein graduated from the Federal polytechnic school in 1900, duly certified as competent to teach mathematics and physics.
He successfully acquired Swiss citizenship in 1901 but was rejected for Switzerland mandatory millitary service and could not be accepted for a teaching position in any school in Switzerland within two years of looking for a job.
career life
However with a help of his friend’s father, a friend who was also a classmate, he was able to secure a job at Swiss Patent Office as an assistant examiner-level III. In 1903, he was confirmed in permanent basis in the company.
It is suspected that his work experiences in the job contributed to his insights about his special theory of relativity.
He stayed in his job long time without being promoted because they claimed that he could not master machine technology.
He arrived at his revolutionary ideas about space, time and light through imagining experiments about the transmission of signals and the synchronization of clocks, matters which also figured in some of the inventions submitted to him for assessment.
In 1902, together with friends he had met in Bern, they formed a science club they called ‘Olympia Academy’ in which they met regularly to discuss science and philosophy.
When in sabbatical leave as a civil servant, he secured a junior teaching position at the University of Bern.
A lecture he gave on relativistic electrodynamics in 1909 in University of Zurich as an invited guest earned him a position in the university as an associate Professor through the influence of Alfred Kleiner, A Swiss Physicist and a professor of Experimental Physics at the University of Zurich.
He was promoted to full professorship in 1911 when he accepted a position of departmental chair at the German Charles-Ferdinand University of Prague in Czech republic which caused him citizenship in Austro-Hungarian Empire.
In 1912, He returned to Federal Institute of Technology in Zurich to take up a position of departmental chair in theoretical Physics.
His fields of specialization in teaching included thermodynamics and analytical mechanics.
His research interests included :
Molecular theory of heat
Continuum mechanics
Development of a relativistic theory of gravitation
He research work was partnered with his friend, Marcel Grossmann, who helped him with mathematical modelling in his works.
Max Plank and Walther Nernst visited Zurich in 1913 and successfully convinced Einstein to relocate to Berlin using their influence to provide him positions in Prussian Academy of science, kaiser Wilhem Institute of Physics and Humboldt University with good salary but without teaching duties that could burden him. He partly accepted their offer because Berlin was a home to his girlfriend, Elsa Löwenthal.
He moved into an apartment in the Berlin district of Dahlem on April 1914 and was installed in his Humboldt University position after a short time.
Einstein’s Marriage and Relationships
He fell in love with a daughter of a family that had accommodated him while he was trying to finish secondary school at the Argovian cantonal school (a gymnasium) in Aarau, Switzerland.
While in polytechnic, he befriended the only woman in their class, Serbian, Mileva Marić and Einstein spent most of his time in college with her as they discussed their shared interest in physics and who become his study partner.
He married his first wife, Serbian, Mileva Marić in 1903 and they gave birth to a son called Hans Albert while they were in Bern, Switzerland In 1904.
While in Zurich, Their second son Eduard was born in 1910.
Einstein entered into a relationship with Elsa Löwenthal In 1912, who was both his first cousin on his mother’s side and his second cousin on his father’s. This caused Marić to return to Zurich with her two sons and they successfully applied for a divorce in 1919 on the grounds of having lived apart for five years. Einstein married Elsa Löwenthal the same year.
Four years later he began a relationship with a secretary named Betty Neumann, the niece of his close friend Hans Mühsam.
Löwenthal nevertheless remained loyal to him, accompanying him when he emigrated to the United States in 1933. In 1935, she was diagnosed with heart and kidney problems and She passed on in December 1936.
A volume of letters discovered by Hebrew University of Jerusalem added further names to the list of women he was romantically related to. About six of them.
After being widowed, Einstein was briefly involved in a relationship with Margarita Konenkova who was believed to be a Russian spy and who was married to a Russian sculptor Sergei Konenkov.
His son eduard was diagnosed with schizophrenia. He spent the remainder of his life in the care of his mother or sometimes in asylum. After death of his mum, he was permanently committed to Burghölzli, the Psychiatric University Hospital in Zürich, until his death in 1965.
Mileva Marić suffered a severe stroke and died at age 72 in 1948, in Zürich. She was burried at Nordheim-Cemetery.
Rise to Fame
Einstein began his new life as an intellectual icon in America after arriving there on 2nd April 1921. He was welcomed to New York City by Mayor John Francis Hylan and then spent three weeks giving lectures and attending receptions. He spoke several times at Columbia University and Princeton and in Washington, he visited the White House with representatives of the National Academy of Sciences. He returned to Europe via London, where he was the guest of the philosopher and statesman Viscount Haldane. He used his time in the British capital to meet several people prominent in British scientific, political or intellectual life, and to deliver a lecture at King’s College.
Einstein and politics
Einstein’s political view was in favor of socialism and he was noted criticizing capitalism. He was among the founder of a political party, German Democratic party.
He was called on to give judgments and opinions on matters related to society away from science and mathematics.
He criticized a political party that took power in Germany in 1917 for not having a well regulated system of government and called their rule a regime of terror and a tragedy in human history.
He strongly advocated the idea of a democratic global government that would check the power of nation states in the framework of a world federation.
Contribution to science
He published more than 300 scientific papers and 150 non-scientific ones.
On 5 December 2014, universities and archives announced the release of Einstein’s papers, comprising more than 30,000 unique documents.
He also collaborated with other scientists on additional projects including the Bose–Einstein statistics, the Einstein refrigerator and many others works.
His Annus Mirabilis papers of 1905 contains four articles pertaining to the photoelectric effect which gave rise to quantum theory, Brownian motion, special relativity and the famous Einstein’s equation, E=mc2. This four articles contributed immensely to the foundation of modern Physics and changed views about space, time and matter.
His paper submitted in 1900 to Annalen der Physik was published in 1901 with the title “Conclusions from the capillary phenomena” that describes capillary attraction.
Two papers he published between 1902 and 1903 were the foundations on publication about Brownian motion which showed that Brownian Movement can be constructed as firm evidence that molecules exist.
The theory of critical opalescence publication discussed the problem of thermodynamic fluctuations giving a treatment of the density variations in a fluid at its critical point.
His paper on On the Electrodynamics of Moving Bodies published on June 1905 resolved the conflicts between Maxwell’s equation and the laws of Newtonian mechanics by introducing changes to the laws of mechanics.
He developed the Theory of general relativity between 1907 and 1915 that has become an essential tool in modern astrophysics providing the foundation for the current understanding of black holes.
In 1911, He published an article on the Influence of Gravitation on propagation of light adding on 1907 publications in which he estimated the amount of deflection of light by massive bodies enabling theoretical predictions of general relativity to be tested experimentally for the first time.
In 1916, Einstein predicted gravitational waves ripples in the curvature of spacetime which propagate as waves, traveling outward from the source, transporting energy as gravitational radiation.
He started a research about general relativistic field theory where he looked for fully generally covariant tensor equations and searched for equations that would be invariant under general linear transformations only which gave birth to the draft theory of 1913.
Einstein applied general theory of relativity to the structure of the universe as a whole. He discovered that the general field equations predicted a universe that was dynamic, either contracting or expanding.
Einstein collaborated with Nathan Rosen to produce a model of a wormhole, often called Einstein–Rosen bridges in 1935.
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