Advice 1: How to determine the direction of the magnetic lines

Any conductor with a current of moving charged particles, magnets, create a magnetic field. Defining the direction of the magnetic lines, you can figure out how it will impact on nearby charged objects.
How to determine the direction of the magnetic lines
You will need
  • the source current (conductor, solenoid);
  • - the right hand;
  • - magnetic hands.
To find the direction of magnetic lines for a straight conductor with current, position it so that the electric current was in the direction from you (for example, a sheet of paper). Try to remember how to move the drill or screwdriver to tighten the screw clockwise and forward. Draw this gesture in order to understand the direction of the lines. Thus, the magnetic field lines are directed clockwise. Check them schematically in the drawing. This method is called corkscrew rule.
If the handler is not in that direction, mentally stand that way, or rotate the design so that the current from you was removed. Then, remember the movement of the drill or screw and set the direction of the magnetic lines in a clockwise direction.
If the rule of thumb seems to be difficult, try using the right hand rule. In order to determine the direction of magnetic lines, place a hand use your right hand with protruding thumb. The thumb channel on the movement of the conductor, and the remaining 4 fingers in the direction of the induced current. Now please note, the magnetic field lines enter the palm of your hand.
In order to use the right hand rule for coils with current grasp it mentally palm of his right hand so that the fingers pointing along the current in the coils. View, which looks set aside the thumb is the direction of the magnetic lines inside the solenoid. This method will help to determine the orientation of metal bars, if you need to charge a magnet with a coil with a current.
To determine the direction of magnetic lines with the help of the magnetic needle, place a few of these arrows around the wire or coil. You will see that the axis of the arrows is directed along the tangents to the circle. Using this method it is possible to find the direction lines at each point of space and to prove their continuity.

Advice 2 : How to determine the visibility of the drawing

In the process of creating the drawing, an engineer is faced with a whole range of problems, the ability to decide which is the extent of his qualifications. The visibility determination in the drawings complex parts is one of these problems. The most common method of determining visibility in the drawing – a method of competitive points.
How to determine the visibility of the drawing
You will need
  • Image details without some visibility at least in two main types, exciting the front view, it is better suited top and front views, marked key points in the drawing, in which visibility is determined.
Locate the drawing point, the projection of which on any plane are the same, not coinciding at the same time on the other plane of projection. Such points are called rival and they will be used as reference points in the construction of appearances, telling us information about the location in space of the objects to which these points are linked.
Using you noted earlier point to determine visibility, direct swipe so that they were perpendicular to one of principal planes of projections, while automatically becoming parallel to the other plane of projection.
Mark the points of intersection of lines in the previous step, with the detail. These points are competing, since their projections on the same plane will be the same, not coinciding at the same time on another plane. If the projection points coincide in the frontal plane (P1), such points are called front competing. If the projection points coincide on a horizontal plane (P2), these points are called horizontal competing.
Determine visibility. For front competing points visibility is determined from the top view. The point the horizontal projection of which is located lower, i.e. closer to the observer, is visible in the front view. Accordingly another point, contending this will be invisible. For horizontally competing points of visibility is determined on the front view, while the dot is visible which is above the rest, and everyone else competing this will not be visible.

Advice 3 : How to determine the direction of current

The true direction of current is that in which moving charged particles. It, in turn, depends on the sign of their charge. In addition, conventional techniques use the direction of movement of charge, not depending on the properties of the conductor.
How to determine the direction of current
To determine the true direction of travel of charged particles, consider the following rule. Inside source they are emitted from the electrode that is charged with the opposite sign, and move toward the electrode, which for this reason acquires a charge similar to the charge sign of particles. In the external circuit, they are pulled by the electric field from the electrode, the charge coincides with the charge of particles, and are attracted to oppositely charged.
The metal carriers of the current are free electrons moving between the nodes of the crystal lattice. Since these particles are negatively charged, the inside source, think of them as moving from the positive to the negative electrode and in the external circuit from the negative to the positive.
In the non-metallic conductors the charge transfer is also electrons, but the mechanism of their movement is different. Electron, leaving the atom and thereby turning it into a positive ion, forcing him to grab the electron from the previous atom. The same electron that left the atom ionizes negatively following. The process is repeated continuously until the circuit current flows. The direction of motion of charged particles in this case read the same as in the previous case.
Semiconductors are of two types: with electronic and hole conductivity. In the first charge carriers are electrons, so the direction of movement of the particles in them can be considered the same as in metals and non-conductors. In the second charge transfer virtual particles - holes. Basically we can say that it is a kind of empty space, electrons which do not exist. Due to the successive shift of the electron holes move in the opposite direction. If you combine two semiconductors, one of which has an electronic and the other hole conductivity, such a device is called a diode, will have rectifying properties.
In vacuum the charge as electrons moving from the heated electrode (cathode) to the cold (the anode). Note that when the diode rectifies the cathode is negative relative to the anode, but relative to the common wire, which is attached to the opposite anode output of the secondary winding of the transformer, the cathode is positively charged. There is no contradiction, if to take into account the voltage drop across any diode (both vacuum and solid state).
In gases, the charge transfer positive ions. The direction of movement of charges in them, consider the opposite direction of their movement in metals, non-metallic rigid conduits, vacuum and semiconductors with electron conductivity, and is similar to the direction of their movement in semiconductors with hole conductivity. Ions are much heavier than electrons, making the gas-discharge devices have high inertia. Ionic devices with symmetric electrodes do not possess a unilateral conductivity, and steel - have her in a certain range of differences of potentials.
In liquids the charge is always carrying heavy ions. Depending on the composition of the electrolyte, they can be both negative and positive. In the first case, consider their behave similarly to the electrons, and the second similarly positive ions in gases or holes in semiconductors.
When specifying the direction of current in an electric circuit, regardless of where you move charged particles in fact, consider moving the source from the negative pole to the positive, and in the external circuit from the positive to the negative. The specified direction is considered conditional, and adopted it before the discovery of atomic structure.

Advice 4 : Why the need for magnetic designer

The goal of any toy is to not only entertain the child, but to develop it aiming in the right direction intellectual ability of the baby. Magnetic designer fully meets this requirement. Collecting figures and creating new forms of magnetic parts, the child uses creative, analytical, and mathematical thinking.
Butterfly magnets

Magnetic designer and development of the child

Magnetic construction appeared on the market recently. Purchase a set of magnets, adults often have trouble imagining what they bought. In order to understand the principles of operation of the toy, you should read the instructions. In the instructions you will find a few ways to build basic models. Magnetic construction designed to create a variety of shapes and forms, including three-dimensional.

The main advantage of magnetic designer is that he does not drive the imagination of the child in the frame, and enables him to do. In the instructions you can find some basic shapes, which folded, the child learns to "drive" his new toy. Then connects imagination, and the baby begins to create, creating new, fantastic shapes.

In the magnetic designer is the connection of different parts. Within each part are the magnets. With the help of magnets items can be attached to each other by either party. There are several modifications of the magnetic sets. For the smallest magnetic boards with flat elements. For older children – the details, allowing you to create large three-dimensional shapes. Popular sets of small magnetic balls and sticks.

Application in learning

Using constructors with magnetic elements allows to shift the learning process to a new level. The creation of three-dimensional shapes of small details develops motor skills, helps to open the child new skills. During the game the child learns about shapes, learning to coordinate their movements.

Teachers use magnetic constructors as visual AIDS. From parts you can build a form showing the structure of the molecules. Or to recreate a human skeleton in a three-dimensional projection. Or to show the children three-dimensional geometric shapes. The opportunity to see and touch with their hands the model of different pieces several times improves the assimilation of new material in school.

Safety rules

Magnetic constructors contain many small parts, so buy them with caution, given the age characteristics of children. Particularly dangerous are small magnetic balls that are included with many sets. These details can easily penetrate the mouth, ear, nose. So for kids it is recommended to buy magnetic boards with great details.
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