“Study of the movement of a body in a circle” - Dynamics of the movement of bodies in a circle. Movement of bodies in a circle. A basic level of. P.N. Nesterov. Decide for yourself. We check the answers. Studying the problem solving method. Algorithm for solving problems. Run the test. Body weight. Solve the problem.
"Reactive Systems" - Humanity will not remain on Earth forever. Soviet rocket system. Jet motion in nature. Squid. Jet propulsion in technology. Two-stage space rocket. Konstantin Eduardovich Tsiolkovsky. Law of conservation of momentum. "Katyusha". Sergei Pavlovich Korolev. Squid can be delicious. Jet propulsion.
“Conductivity of semiconductors” - Questions for control. Conductivity of silicon-based semiconductors. Full-wave rectifier circuit. Consider the electrical contact of two semiconductors. Reverse inclusion. The main property of the p–n junction. Half-wave rectifier circuit. Different substances have different electrical properties. Changes in semiconductor. Electric current in various environments. P–n junction and its electrical properties.
“Field strength” - Which arrow in the figure indicates the direction of the electric field strength vector. Electric field. Field strength. The principle of superposition of fields. What is the direction of the electric field strength vector. Indicate the point at which the field strength can be zero. Creators of electrodynamics. Field strength of a point charge. The tension at point O is zero. The electrostatic field is created by a system of two balls.
“Types of lasers” - Liquid laser. Solid state lasers. Chemical laser. Classification of lasers. Ultraviolet laser. Source of electromagnetic radiation. Semiconductor laser. Laser. Application of laser. Properties of laser radiation. Amplifiers and generators. Gas laser.
“Heat engines” 10th grade” - Team members. Steam turbine. Protection of Nature. Engine efficiency. A little about the creator. Tsiolkovsky. Three-wheeled stroller invented by Karl Benz. James Watt. Steam engines and steam turbines have been and are being used. Diesel engines. Rocket engine. The engine operates on a four-stroke cycle. For those who want to reach the stars. Denis Papin. Archimedes. The principle of operation of the turbine is simple. Types of internal combustion engines.
In the bitter alpine winter, the ice turns to stone.The sun is then unable to melt such a stone.
Claudian 390
CRYSTALS.
CRYSTAL
SUBSTANCES
Performed
10th grade student
Kazachanskaya Ekaterina
Goal of the work:
Study the properties and types of crystallinesubstances, their practical significance.
Job objectives:
Consider:
- types of crystals;
- basic growing methods
crystals;
Find out what natural and
artificial crystals.
Relevance of the topic
Since crystals have a wideapplication in science and technology, it is difficult
name a branch of production where there is no
crystals would be used.
I was wondering:
- what is a crystal?
- how crystals grow;
- what properties do they have;
- where are they used?
Diamond (diamond)
Hypothesis put forward:
Crystals are the basis of life on earth.The concepts of “crystal” and “life”
- not mutually exclusive.
Symbol of inanimate nature crystal -
alive!
Crystals can be grown. Crystals (from the Greek krystallos, original.
- ice), solids, atoms or molecules
which form an ordered
periodic structure (crystalline
grate).
Anyone who has visited the Museum of Mineralogy
or at a mineral exhibition, I couldn’t help but
admire the grace and beauty of forms,
that take in “non-living” substances.
Tourmaline
Beryl
Strontianite
Cerussite Ice crystals
Ordered three-dimensional arrangement of molecules
characteristic of crystals and distinguishes them from others
solids. aquamarine
STRUCTURE OF CRYSTALS
The variety of crystals in shape is very large.Crystals can have from four to several
hundreds of edges. But at the same time they have
remarkable property - whatever
size, shape and number of faces of the same
crystal, all flat faces intersect with each other
each other at certain angles. Angles between
the corresponding faces are always the same.
Rock salt crystals, for example, may have
the shape of a cube, parallelepiped, prism or solid
more complex shapes, but always their edges
intersect at right angles. Quartz facets
have the shape of irregular hexagons, but
The angles between the faces are always the same - 120°.
The law of constancy of angles, discovered in 1669
Danish Nikolai Steno, is the most important
the law of the science of crystals - crystallography.
Measuring angles between crystal faces
is of very great practical importance, since
based on the results of these measurements in many cases
the nature can be reliably determined
mineral.
The simplest device for measuring angles
crystals is an applied goniometer.
Rhinestone
Sapphire
Types of crystals
crystalssingle crystals
polycrystals
A monocrystal is a monolith with a single
undisturbed
crystalline
lattice.
Natural
Large single crystals are very rare.
Single crystals include quartz, diamond, ruby and many
other precious stones.
Most crystalline solids are
polycrystalline, that is, they consist of many small
crystals,
Sometimes
prominent
only
at
strong
increase.
All metals are polycrystals. crystals
natural
Ametrine
artificial
Marble
Diamonds
Quartz
Corals
Emerald
Artificial
pearl
Natural crystals
Natural crystals are alwaysaroused people's curiosity. Their
color, shine and shape affected
human sense of beauty, and
people decorated themselves and their homes with them.
Since ancient times there have been crystals
associated superstitions; they are like amulets
had to not only protect
their owners from evil spirits, but also
give them supernatural powers
abilities.
Later, when the same
minerals began to be cut and
polish like precious stones
many superstitions persist in
talismans “for luck” and “their
stones" corresponding to the month
birth.
Agate
Peridot
Ruby
Aquamarine
Natural crystals
FrostSulfur
Rock salt
Corals
In nature, crystals are formed by three
ways: from the melt, from solution and from vapor.
An example of crystallization from a melt
is the formation of ice from water.
An example of the formation of crystals from
solutions can last hundreds of millions
tons of salt that fell from sea water.
An example of the formation of crystals from steam
and gas are snowflakes and frost. Air,
containing moisture, is cooled, and directly from
it grows snowflakes of one kind or another
forms.
Many crystals are products
vital activity of organisms. This
for example, pearls, mother of pearl.
Reefs and entire islands in the oceans are stacked
from crystals of calcium carbonate,
forming the basis of the skeleton
invertebrates - corals
polyps.
Artificial crystals
For many branches of technology,carrying out scientific research
crystals are required
high chemical purity with
perfect crystalline
structure.
Crystals found in
nature, these requirements do not
satisfy as they grow in
conditions very far from
ideal
In addition, the need for
exceeds many crystals
reserves in natural
deposits.
From more than 3000 minerals,
existing in nature,
artificially managed to obtain
more than a half.
Synthetic quartz
Artificial pearls crystals
Applications of crystals
From the previous table it is clear that crystals are widelyused in science and technology: semiconductors, prisms and lenses
for optical devices, lasers, piezoelectrics,
ferroelectrics, optical and electro-optical crystals,
ferromagnets and ferrites, single crystals of high-quality metals
cleanliness...
About 80% of all natural diamonds mined and all
artificial diamonds are used in industry
X-ray structural studies of crystals allowed
establish the structure of many molecules, including biological ones
active - proteins, nucleic acids.
Today it is difficult to name a branch of production in which
crystals would not be used.
Rhinestone
Diamonds in the Rough
Diamond Faceted gemstone crystals,
including those grown artificially,
are used as decorations.
Crystals are the basis of life!
A crystal usually serves as a symbol of inanimate nature. However, the line betweenIt is very difficult to establish living and nonliving things, and the concepts of “crystal” and “life” are not
are mutually exclusive.
Firstly, the simplest living organisms - viruses - can combine into
crystals.
In the crystalline state they show no signs
alive, but when external conditions change to favorable (such as for viruses
are the conditions inside the cells of a living organism) they begin to move,
multiply.
Secondly, in living organisms the DNA molecule is a double
a helix made up of a small number of relatively simple molecular units
compounds repeated in a strictly defined order for a given type.
The diameter of a DNA molecule is 2*10-9 m, and the length can reach several
centimeters. Such giant molecules from the point of view of physics are considered as
a special type of solid is one-dimensional aperiodic crystals. Hence,
crystals are not only a symbol of inanimate nature, but also the basis of life on Earth.
Molecule
DNA
Crystals in plant cells
Growing Crystals
We are able to grow crystals thanks tocrystallization - the process of formation
crystals from vapors, solutions, melts.
Crystallization begins when it reaches
some limiting condition, for example,
supercooling of liquid or supersaturation of steam,
when almost instantly a multitude arises
small crystals - crystallization centers.
Crystals grow by adding atoms or
molecules from liquid or vapor. Face growth
the crystal occurs layer by layer, the edges
incomplete atomic layers move during growth
along the edge. Dependence of growth rate on
crystallization conditions leads to diversity
shapes and structures of crystals. Methods for growing crystals.
Crystallization can be carried out in different ways.
One of them is cooling a saturated hot solution.
When a solution is cooled, particles of a substance (molecules, ions)
which can no longer be in a dissolved state, stick together
with each other, forming tiny crystal nuclei.
If the solution is cooled slowly, few nuclei are formed, and
gradually growing on all sides, they turn into beautiful
crystals of regular shape.
With rapid cooling, many nuclei are formed, correct
In this case, crystals will not form, because those in solution
particles may simply not have time to “settle” on the surface of the crystal for
their proper place. Druses are formed - clusters, clusters of small
crystals.
Druze and
crystals
salt Another method for obtaining crystals is gradual removal
water from a saturated solution. The “extra” substance in this case
crystallizes. And in this case, the slower the water evaporates,
the better the crystals turn out.
The third method is cultivation
crystals from molten
substances at slow
cooling the liquid. At
using all methods
best results
are obtained if used
seed - a small crystal
correct shape, which
placed in a solution or melt.
In this way one gets
for example, ruby crystals.
Ruby
Growing Crystals
Equipment: table salt, distilled water, funnel,glass rod, cotton wool, glasses.
Work order:
I thoroughly washed 2 glasses and a funnel and held them over steam
poured 100 gr. hot water into a glass. Prepared a saturated solution
salt and poured it through a cotton filter into a clean glass. Closed the glass
lid. Wait until the solution cools to room temperature and
opened the glass. After some time, crystals began to fall out. The growth of my polycrystal from table salt
(NaCl) occurred within 16 days. Growth of a single crystal of copper sulfate
(CuSO4·5H2O) occurred over 7 days.
The place where the crystals grew
Grown salt crystalhas a cubic shape with
slight deviations.
The sides of the crystal are smooth and have
the shape of rectangles.
The initial feeling is that
it's grown together a lot
squares and rectangles,
This is what the crystal looked like.
The crystal of copper sulfate had
parallelogram shape.
Conclusion: In this experiment I
learned to grow crystals
table salt and copper
vitriol, and I also learned that this
way you can grow
crystals of any other simple
substances and what is needed for
cultivation, and how it happens
crystal growth.
Pupils of the 10th grade “A” of Secondary School No. 1997 Khachatryan Knarik Checked by: Pankina L.V. In physics Topic: Amorphous bodies
Amorphous bodies Amorphous bodies are bodies that, when heated, gradually soften and become more and more fluid. For such bodies it is impossible to indicate the temperature at which they turn into liquid (melt)
Crystalline bodies Crystalline bodies are bodies that do not soften, but turn from a solid state immediately into a liquid. During the melting of such bodies, it is always possible to separate the liquid from the not yet melted (solid) part of the body.
Examples Amorphous substances include glass (artificial and volcanic), natural and artificial resins, glues and other rosin, sugar candy and many other bodies. All these substances become cloudy over time (glass “devitrifies,” candy “candied,” etc.). This clouding is associated with the appearance inside the glass or candy of small crystals, the optical properties of which are different from those of the surrounding amorphous medium.
Properties Amorphous bodies do not have a crystalline structure and, unlike crystals, do not split to form crystalline faces; as a rule, they are isotropic, that is, they do not exhibit different properties in different directions, and do not have a specific melting point.
How do amorphous bodies differ from crystals? Amorphous bodies do not have a strict order in the arrangement of atoms. Only the nearest neighbor atoms are arranged in some order. But there is no strict repeatability in all directions of the same structural element, which is characteristic of crystals, in amorphous bodies. In terms of the arrangement of atoms and their behavior, amorphous bodies are similar to liquids. Often the same substance can be found in both crystalline and amorphous states. For example, quartz SiO2 can be in either crystalline or amorphous form (silica).
Liquid crystals. In nature, there are substances that simultaneously possess the basic properties of a crystal and a liquid, namely anisotropy and fluidity. This state of matter is called liquid crystalline. Liquid crystals are basically organic substances whose molecules have a long thread-like or flat plate shape. Soap bubbles are a prime example of liquid crystals
Liquid crystals. Refraction and reflection of light occurs at the domain boundaries, which is why liquid crystals are opaque. However, in a layer of liquid crystal placed between two thin plates, the distance between which is 0.01-0.1 mm, with parallel depressions of 10-100 nm, all the molecules will be parallel and the crystal will become transparent. If electrical voltage is applied to some areas of the liquid crystal, the liquid crystal state is disrupted. These areas become opaque and begin to glow, while the areas without tension remain dark. This phenomenon is used in the creation of liquid crystal television screens. It should be noted that the screen itself consists of a huge number of elements and the electronic control circuit for such a screen is extremely complex.
Solid State Physics Obtaining materials with specified mechanical, magnetic, electrical and other properties is one of the main areas of modern solid state physics. Amorphous solids occupy an intermediate position between crystalline solids and liquids. Their atoms or molecules are arranged in relative order. Understanding the structure of solids (crystalline and amorphous) allows you to create materials with desired properties.
Ionic crystal lattice There are ions at the lattice sites. The chemical bond is ionic. Properties of substances: 1) relatively high hardness, strength, 2) fragility, 3) heat resistance, 4) refractoriness, 5) non-volatility Examples: salts (NaCl, K 2 CO 3), bases (Ca(OH) 2, NaOH)
Atomic crystal lattice There are atoms at the lattice sites. The chemical bond is covalent nonpolar. Properties of substances: 1) very high hardness, strength, 2) very high melting point (diamond 3500 ° C), 3) refractory, 4) practically insoluble, 5) non-volatile Examples: simple substances (diamond, graphite, boron, etc.), complex substances (Al 2 O 3, SiO 2) diamond graphite
Molecular crystal lattice At the lattice sites of the molecule. Chemical bond covalent polar and non-polar. Properties of substances: 1) low hardness, strength, 2) low melting point, boiling point, 3) at room temperature usually liquid or gas, 4) high volatility. Examples: simple substances (H 2, N 2, O 2, F 2, P 4, S 8, Ne, He), complex substances (CO 2, H 2 O, sugar C 12 H 22 O 11, etc.) iodine I 2 carbon dioxide CO 2
Law of constancy of composition (Proust) Molecular chemical compounds, regardless of the method of their preparation, have a constant composition and properties.
