Magnetic Experiments

Hi Friends

Good Morning!!! Today let us learn about Magnetic attraction.

As you will see from these magnetic experiments, magnetism (the invisible force) can push and pull through some materials such as paper and plastic.

Paper clips are made of steel. If you hold a paper clip close to a magnet, you can feel the magnet pulling on the paper clip with an invisible force called magnetism.

All magnets have two ends or poles (North & South). If you put the poles of two magnets together, they will either pull together or push apart. They will pull (attract) each other if the poles are different. They will push (repel) each other if the poles are the same.

Experiments with magnets will help you to find out more about the way magnetism works and how it can be passed on to some other objects.

Look for magnets in old toys or on fridge stickers, or buy a bar or horseshoe magnet from a toy shop.

Electromagnetic relays are devices that connect and disconnect contact points physically using an electromagnet.

The magnetic attraction that activates the relay is generated by the magnetomotive force, which is expressed by the product of coil turns and current.

The operating time can be calculated from the magnetic attraction at the moveable core using an equation of motion.

This example presents the use of a magnetic field analysis to evaluate the operating time of an electromagnetic relay driven by direct current accounting for the eddy currents.

Keep reading and leave your comments.

Climatic Conditions on Mars

Good Afternoon my little friends!!!

I am back again with an interesting topic, as i do every day. Have you learned anytime about Mars?Today we shall understand about "Climatic Conditions on Mars"

Climatic Conditions on Mars

• Type : Earth like

• Seasons : Earth like due to similarities in tilts of the rotational axes of the planets.

• Lenght of seasons : Twice as those on Earth

• Thermal conservation : Poor ,due to thin atmosphere

• Amount of incident light : 43% of Earth

• Storms : Largest dust storm in solar system

• 

Soil structure of Mars

(Data from Phoenix Lander, June 2008, august 2008)
Nature of soil : Basic, pH 8.3
Vital nutrients: Magnesium, Potassium and chloride, salt perchlorate
Life : dark streaks common across martian soil in may involve water or even growth

In our next blog we shall learn about "Mars orbits"

Hope the above explanation was useful. keep reading and leave your comments.

How do Robots Work?

As the world embraces technology, some of the world’s population is still trying to catch up. While there’s plenty of elderly out there that take to the advancements of our phones, computers, and even our eyes, there’s just as many out there that find the whole situation far too complex for every day usage.

Robots are mechanical devices that operate automatically. They can perform a wide variety of tasks; jobs that are repetitious and boring, difficult, or too dangerous for people to perform. Industrial robots efficiently complete routine tasks such as drilling, welding, assembly, painting, and packaging. They are used in manufacturing, electronics assembly, and food processing.

The word robot comes from the Czech word 'robota' that means drudgery. The science and technology that deals with robots is called robotics. A typical robot completes its task by following a set of specific instructions that tell it what and how the job is to be completed. These instructions are programmed and stored in the robot's control center, a computer or partial computer. Robots come in different sizes and shapes. Few resemble humans as is frequently depicted in science fiction. Most are stationary machines with a single arm that lifts or moves objects and uses tools.

Engineers have also developed mobile robots with video cameras for sight and electronic sensors for touch. These new generation robots are controlled by both their stored instructions by feedback that they receive from the sensors. Such robots might be used on the ocean floor at depths man is unable to reach and in planetary exploration and other scientific research.

Robots doing battle on Earth, robots helping humans to fight evil, or a robot which has committed murder – these are just some of the ways in which robots have been featured in Hollywood films in recent years.

We are all obsessed with robots. What they can do and how they can benefit humans, the possibilities are limitless. Let's find out how robots do what they do.

At the very basic level, robots are very much like humans. They are made up of five basic components:

1) A body structure

2) A muscle system which enables it to move

3) A sensory system that receives information about its body and from its surroundings

4) A power source that activates the muscle and sensory systems

5) A brain system that processes sensory information and tells the body what to do.

Types of Robot

• Cartesian robot /Gantry robot: Used for pick and place work, application of sealant, assembly operations, handling machine tools and arc welding. It's a robot whose arm has three prismatic joints, whose axes are coincident with a Cartesian coordinator.
• Cylindrical robot: Used for assembly operations, handling at machine tools, spot welding, and handling at diecasting machines. It's a robot whose axes form a cylindrical coordinate system.
• Spherical/Polar robot: Used for handling at machine tools, spot welding, diecasting, fettling machines, gas welding and arc welding. It's a robot whose axes form a polar coordinate system.
• SCARA robot: Used for pick and place work, application of sealant, assembly operations and handling machine tools. It's a robot which has two parallel rotary joints to provide compliance in a plane.
• Articulated robot: Used for assembly operations, diecasting, fettling machines, gas welding, arc welding and spray painting. It's a robot whose arm has at least three rotary joints.
• Parallel robot: One use is a mobile platform handling cockpit flight simulators. It's a robot whose arms have concurrent prismatic or rotary joints.
  

In our next blog shall learn to make Robot.

Keep reading and leave your comments.

Physics in relation to science, society and technology

Let Us Learn About Physics in relation to science, society and technology

Physics in relation to science, society and technology

Technology has also a very important part in a society. People reach another level, countries grow, economy grows because technology and inventions appear and help people produce. Technology helps communication develop also. Communication Technology In Society, is recognized by all the gadgets and all the things through which people communicate easily. For example mobile phones or computers and Internet. Each day something new appears and brings us to another level.

Among the various disciplines of science, the only discipline which can be regarded as being most fundamental is physics.

It has played a key role in the development of all other disciplines.

Physics in relation to chemistry

The study of structure of atoms, radioactivity, X-ray, diffraction, etc., in physics has enabled chemists to rearrange elements in the periodic table and to have a better understanding of chemical bonding and complex chemical structures.

Physics in relation to Biological science

The optical microscopes developed in physics are extensively used in the study of biological samples.

Electron microscope, X-rays and radio isotopes are used widely in medical sciences.

Physics in relation to astronomy

The giant astronomical telescopes and radio telescopes have enabled the astronomers to observe planets and other heavenly objects.

Physics related to mathematics

Mathematics has served as a powerful tool in the development of modern theoretical physics.

Physics related to other sciences

The other sciences like Biophysics, Geology, Heterology and Oceanography and Seismology use some of the laws of physics.

Physics related to society and technology

The development of telephone, telegraph and telex enables us to transmit messages instantly.

The development of radio and television satellites has revolutionised the means of communication.

Advances in electronics (computers, calculators and lasers) have greatly enriched the society.

Rapid means of transport are important for the society.

Generation of power from nuclear reactors is based on the phenomenon of controlled nuclear chain reaction.

Digital electronics is widely used in modern technological developments.

Keep reading and leave your comments

Molecular Definition of Pressure

Let Us Study About Pressure

Pressure is determined by the flow of mass from a high pressure region to a low pressure region. Pressure measurements are made on the fluid states--liquids and gases. Air exerts a pressure which we are so accustomed to that we ignore it. The pressure of water on a swimmer is more noticable. You may be aware of pressure measurements in relations to the weather or your car or bicycle tires.

PRESSURE is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside. Pressure is a property which determines the direction in which mass flows. If the balloon is released, the air moves from a region of high pressure to a region of low pressure.

Atmospheric pressure varies with height just as water pressure varies with depth. As a swimmer dives deeper, the water pressure increases. As a mountain climber ascends to higher altitudes, the atmospheric pressure decreases. His body is compressed by a smaller amount of air above it. The atmospheric pressure at 20,000 feet is only one-half of that at sea level because about half of the entire atmosphere is below this elevation.

Atmospheric pressure at sea level can be expressed in terms of 14.7 pounds per square inch. The pressure in car or bicycle tires is also measured in pounds per square inches. A car should have 26-30 lb/sq.in. and bicycle tires 40-60/sq.in.

Molecular Definition of Pressure

From the kinetic theory of gases, a gas is composed of a large number of molecules that are very small relative to the distance between molecules. The molecules of a gas are in constant, random motion and frequently collide with each other and with the walls of any container. The molecules possess the physical properties of mass, momentum, and energy. The momentum of a single molecule is the product of its mass and velocity, while the kinetic energy is one half the mass times the square of the velocity. As the gas molecules collide with the walls of a container, as shown on the left of the figure, the molecules impart momentum to the walls, producing a force perpendicular to the wall. The sum of the forces of all the molecules striking the wall divided by the area of the wall is defined to be the pressure. The pressure of a gas is then a measure of the average linear momentum of the moving molecules of a gas. The pressure acts perpendicular (normal) to the wall; the tangential (shear) component of the force is related to the viscosity of the gas.

The scientific units of pressure can be determined from its definition:

A force applied to surface with an area A will have will result in a pressure P as defined above. Force has the units "mass length/time^2" and area has the units length^2. Inserting this into the equation above results in the units of pressure as

A pascal is the SI unit of pressure.

Consider gas molecules in a rectangular box. Every time a molecule collides with a wall of the box the collision results in a force on the box. These forces combine and result in the pressure of the gas.

Latent Heat

Let Us Learn About Latent Heat

When a substance changes phase, that is it goes from either a solid to a liquid or liquid to gas, the energy, it requires energy to do so. The potential energy stored in the interatomics forces between molecules needs to be overcome by the kinetic energy the motion of the particles before the substance can change phase.

Latent heat is the energy absorbed or released when a substance changes its physical state. Latent heat is absorbed upon evaporation, and released upon condensation to liquid (as in clouds). Latent heat is also absorbed when water melts, and released when it freezes.

Latent heat is the name given to energy which is either lost or gained by a substance when it changes state, for example from gas to liquid. It is measured as an amount of energy, joules, rather than as a temperature.

If we measure the temperature of the substance which is initially solid as we heat it we produce a graph like

Temperature change with time. Phase changes are indicated by flat regions where heat energy used to overcome attractive forces between molecules

Starting a point A, the substance is in its solid phase, heating it brings the temperature up to its melting point but the material is still a solid at point B. As it is heated further, the energy from the heat source goes into breaking the bonds holding the atoms in place. This takes place from B to C. At point C all of the solid phase has been transformed into the liquid phase. Once again, as energy is added the energy goes into the kinetic energy of the particles raising the temperature, (C to D). At point D the temperature has reached its boiling point but it is still in the liquid phase. From points D to E thermal energy is overcoming the bonds and the particles have enough kinetic energy to escape from the liquid. The substance is entering the gas phase. Beyond E, further heating under pressure can raise the temperature still further is how a pressure cooker works.

Latent Heat of Fusion and Vaporization

The energy required to change the phase of a substance is known as a latent heat. The word latent means hidden. When the phase change is from solid to liquid we must use the latent heat of fusion, and when the phase change is from liquid to a gas, we must use the latent heat of vaporization.

The energy require is Q= m L, where m is the mass of the substance and L is the specific latent heat of fusion or vaporisation which measures the heat energy to change 1 kg of a solid into a liquid.

Internal Energy

Let Us Learn About Internal Energy

Internal Energy is the energy stored in a system at the molecular Level. The System's Thermal Energy -the Kinetic Energy of the atoms due to their random motion relative to the Center of Mass plus the binding energy (Potential Energy) that holds the atoms together in terms of atomic bonds.

We consider all possible internal changes to the body as making up the total internal energy.

There are two ways to change the internal energy: with work, and everything else. Everything else is defined as heat. Heat is the defined as the transfer of energy to a body that does not involve work or those transfers of energy that occur only because of a difference in temperature. As Bellman would say,

Internal energy is one of the most important concepts in thermodynamics. Energy changes in a body sliding with friction. Warming a body increases its internal energy and cooling the body decreases its internal energy. However, what is internal energy? We can look at it in various ways: let's start with one based on the ideas of mechanics. Matter consists of atoms and molecules, and these are made up of particles having kinetic energy and potential energy. We tentatively define the internal energy of a system as the sum of the kinetic energy of all its constituent particles, plus the sum of all the potential energy of interaction among these particles.

Note that internal energy does not include potential energy arising out of interaction between the system and it surroundings. If the system is a glass of water, placing it on a high shelf, increases the gravitational potential energy arising from the interaction between the glass and the Earth. However, this has no effect on the interaction between the molecules of water, and so the internal energy of water does not change.

We use the symbol 'U' for internal energy. During a change of state of the system, the internal energy may change from an initial value U₁ to a final value U₂. We denote the change in internal energy as .