PHYS_10_1_V2_TG_Role of the physics in modern world

Teacher guide

Teacher’s guide on using the didactic material #1:

-          Print as many tables with the material as you need acording to the number of students in each class;

-          Cut the materials into pieces;

-          Give the cards with tasks to the students randomly (blindfolded, upside down);

-          Make the students do the task;

-          Organize the students with the same answers into one group etc.;

-          Give help to the struggling students;

-          Make the students start the main task (preparing the presentations).

Theoretical material

(Theory is given briefly and randomly on every topic provided in the presentation. The students can find out something rather than this particular parts)

The discoveries of the electron and radioactivity at the end of the 19th century led to different models for the structure of the atom. In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr's theory could explain why atoms emitted light in fixed wavelengths.

While conducting experiments with electricity and vacuum tubes in 1895, Wilhelm Röntgen discovered that his photographic plates were darkened, even when wrapped with black paper. He then concluded that some kind of yet unknown, penetrating rays were at play in his experimental setup. He was able to use this new “X-rays”, as he named them, to take the first X-ray image, using the hand of his wife Anna Bertha. A year later Henri Becquerel found that similar rays were produced naturally by uranium salts.

The phenomenon that produced the X-rays was named radioactivity by Marie Curie, Becquerel´s doctoral student. Marie and her husband Pierre, carried on much of the pioneering work on radioactivity. They discovered new elements with this property, such as radium, polonium, and thorium. Of the 48 women who have been awarded Nobel prizes, Marie Curie is the only one who won the distinction twice: first in physics for her work in radiation phenomena, and then in chemistry, for her discovery of radium and polonium. It is worth to mention that only four persons and two organizations have won multiple Nobel awards.

Marie Curie died in 1934, victim of her work with radiation, since it was not known at the time that radiation posed serious health issues. Her papers and even her cookbook are stored in shielded boxes as they are still highly radioactive and cannot be handed safely.

Electric current exists in only two forms, alternating (AC) and direct (DC). Experimenters discovered direct current electricity in the 1790s by tinkering with early chemical batteries. Since it flows in only one direction, DC is a simple form of electricity. Alternating current, a more complex kind of electricity, was discovered in the late 1800s. It flows back and forth in a rapid wavelike motion.

The modern binary number system, the basis for binary code, was invented by Gottfried Leibniz in 1679 and appears in his article Explication de l'ArithmétiqueBinaire. The full title is translated into English as the "Explanation of the binary arithmetic", which uses only the characters 1 and 0, with some remarks on its usefulness, and on the light it throws on the ancient Chinese figures of Fu Xi." (1703). Leibniz's system uses 0 and 1, like the modern binary numeral system. Leibniz encountered the I Ching through French Jesuit Joachim Bouvet and noted with fascination how its hexagrams correspond to the binary numbers from 0 to 111111, and concluded that this mapping was evidence of major Chinese accomplishments in the sort of philosophical mathematics he admired.

About 25 years ago Zwicky (1957), Holmberg (1958) and Hoffmeister (1962) found intergalactic dust by observations. Zwicky (1957) explained the deficiency of distant clusters of galaxies by intergalactic dust inside the near clusters. Holmberg (1958) made extensive observations of the Virgo cluster. He found systematic differences of the colour indexes between cluster and field galaxies. Intergalactic dust inside of the Virgo cluster should be the reason of these differences. Hoffmeister (1962) found a clear deficiency of galaxies in the region of Microscopicum. Again the reason should be a large cloud of intergalactic dust.

Dr. Warren Kortz of Denver has performed hundreds of operations using robots. On his hospital's website, the Porter Robotics Institute, which is part of Porter Adventist Hospital, robotic surgeries are promoted as the safer, less invasive option.

But the Colorado medical board this week charged Kortz with unprofessional conduct, citing complications in 11 robotic surgeries from 2008 to 2010. In one instance, the robot he was using in the surgery allegedly tore the aorta of a kidney patient.

Kortz and his lawyer declined ABC News' requests for comment.

It is hardly an isolated case of alleged mistakes during robo-surgery.

The Food and Drug Administration announced this week that it is looking into the increasing number of serious medical problems, even deaths, where robotic surgery might have played a role.

Safety Considerations for Specific Physics Topics

Electricity

Locate the master electrical cut-off switch.

Use low voltage DC for studying simple circuits.

The teacher should check all student circuits before the power is connected.

Never touch electrical circuit components with the power on. Only insulated tools should be used to make checks.

The last act in assembling a wired electrical circuit is to insert the plug. The first act in disassembling a wired electrical circuit is to remove the plug.

When using an electrical current, you should use only one hand at a time to avoid bringing both hands in contact with live sections of the circuit.

Electrical batteries should be checked for leakage and not be left in electrical appliances for extended periods of time.

If electrical current is used near a metal object, the object should be permanently insulated to prevent contact. Care should be taken to assure that live wires do not contact grounded metal objects.

Keep away from the fine spray that develops when charging a storage battery.

Carefully handle a storage battery. In spite of its low voltage, a high current can be drawn from it on a short circuit.

Switches should be labeled for "on" and "off" positions.

Proper grounding of equipment should be checked by the teacher before using.

Any equipment with frayed cords or any other visible defects should not be used.

Installation and repair to electrical equipment should not be done by an amateur. Check with your administrator for the appropriate procedures for equipment repair.

Plugs should always be plugged in and pulled out using the plug, not the wire.

Use properly grounded (3 prong - one constant ground) service outlets.

Care should be taken not to spill liquids near electrical outlets.

All potentiometers should be checked by the teacher before use in circuits by students.

If fire does occur with a "live" electrical apparatus, pull the plug then use an appropriate fire extinguisher (Class C), dry chemical - carbon dioxide.

Motion and Forces

Teachers should make sure that devices that are to be stationary should be secured by a C-clamp.

Spring-loaded carts and heavy masses should be used only as directed.

Centripetal force labs should be conducted only with protective goggles. If glass rods are used, they should be fire polished and wrapped in tape. Additional space may be needed to assure the spinning mass does not hit anything. Instructions should be given to caution students never to walk in the path of the spinning masses. Finally, the teacher should check to assure that the mass being used by each group is securely fastened.

A planetary motion hazard is the viewing of solar eclipses. Never view solar eclipses directly; always use an indirect method. (Refer to Earth Science for specific procedures.)

When using model rockets, the safety code of the National Association of Rocketry (NAR) should be followed. Only factory prepared solid engine propellant should be used and only as recommended by manufacturers. Direct supervision is needed by the teacher. (Refer to Earth Science for specific procedures.)

When using any apparatus that rotates, be sure the safety nut is secured.

Energy

Ring stands should be secured with a C-clamp.

Springs should not exceed their elastic limits.

When viewing the pointer on a fixed scale, goggles should be worn.

Heat

Locate master gas valve cut-off and leave master control "off" when not in use.

Closed containers should never be heated.

Use proper technique to insert a thermometer into a rubber stopper to prevent lacerations. (Refer to Biology or Chemistry for specific procedures.)

Goggles and insulated gloves should be worn when using cryogenic fluids.

Bunsen burners should be periodically checked.

Fire retardant pads and gloves should be used when handling hot materials.

Only Pyrex glassware should be used when heating liquids.

Never leave gas jets open.

Refer to Chemistry section for the proper procedure for cleaning up broken mercury thermometers.

A fire blanket and an appropriate fire extinguisher should be available in the vicinity.

Pressure

When using a pressure cooker, do not allow the pressure to exceed 20 pounds per square inch; allow the cooker to cool to room temperature before opening it.

The use of mercury manometers can be hazardous due to the poisonous vapors of mercury. Place a few drops of oil in each tube to cover the mercury and prevent the vapors from escaping. When not in use, the apparatus should be tightly covered and stored securely in a well ventilated room. The teacher is directed to the Chemistry section for the correct procedures to clean up mercury spills.

Light

The use of lenses and prisms in direct sunlight should be supervised.

Caution should be exercised in the use of ultraviolet light sources, such as mercury-quartz lamps or carbon arc lamps that can cause severe sunburn or damage to the retina. Proper instructions, labels, and protective gear should be provided.

Wave motion, when studied with light, generally includes the use of large coil springs or rubber hoses. Care should be given not to exceed the elastic limit of the coils or to release the hose unexpectedly.

Ripple tanks should be set up to assure the stability of the high intensity light, the motor, and the electrical source.

When simulating Young's experiment, caution should be given to handling the delicate slides and the single edge razor blades.

Spectroscope high voltage supplies should be checked prior to classroom use. Students should be cautioned never to touch the ends of the spectrum tube while the voltage supply is connected.

Some students may have physiological or psychological reactions to the effects of a strobe light. (e.g., epilepsy)