Glass made from sand
Glass made from sand
How Is Glass Made?
Glass is made from liquid sand. More specifically, glass is made by heating ordinary sand (mostly composed of silicon dioxide SiO2) until it melts and turns into a liquid. The molten sand is allowed to cool, and it turns into a frozen liquid or an amorphous solid.
Over the course of human history, there was a Stone age, and then a Bronze age, and there’s even been an Iron age. The question is, what moniker would you give to the age in which we’re presently living? Personally, I vote for calling it the Glass Age!
(Image Credit: Flickr)
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Glass is ubiquitous
Today, there is hardly any area of life in which glass is not used in one form or another. The windows of houses, cars, ships, trains, and even the airplanes are made from glass sheets. The list of glass products is practically endless, from water vessels, tumblers, decoration articles, different kinds of bottles and sunglasses to spectacles, flasks, lab items, incandescent bulbs, fluorescent tubes and hundreds of other items we use directly or indirectly in our daily life. Have you ever wondered how this incredibly useful material is made?
Lab apparatus made of glass. (Photo Credits : Pxhere)
Mysticism of Glass: Is Glass a Liquid?
Although glass has a plethora of applications, it also has a tinge of mysticism around it—likely due to its strange chemical and physical behavior. It is strong enough to protect us, but it can also shatter frantically into thousands of pieces. It’s made from opaque sand, yet it’s completely transparent. And, perhaps most startling of all—it appears and behaves like a solid, but it’s actually a form of weird liquid in disguise!
The Science of Making Glass
This might be hard to believe, but glass is made from liquid sand. More specifically, glass is made by heating ordinary sand (mostly composed of silicon dioxide SiO 2 ) until it melts and turns into a liquid. You may wonder why the same thing doesn’t happen on hot days at the beach, but the answer to that is quite simple—the melting temperature that the sand needs is very high, around 1700° Celsius.
Sample of silicon dioxide. (Photo Credit : LHcheM/Wikimedia Commons)
When the molten sand is allowed to cool, it doesn’t return back to its gritty yellow state that you began with—the heating causes it to undergo a complete chemical transformation, thus attaining a new inner structure. Regardless of the technique employed for cooling the molten sand, it never quite sets into a quintessential solid. Instead, it turns into a frozen liquid or—what a material science graduate would like to call—an amorphous solid. Basically, glass is more like a cross between a solid and a liquid, featuring some crystalline structures generally found in solids, as well as some molecular randomness often seen in liquids.
The History of Making Glass
The art of making glass is very old. It is not known with certainty when man first learned to make glass, but some glass beads made as far back as 2500 BC were recently recovered in Egypt. A blue glass rod made around 2600 BC was found in Babylonia. It is clear from these findings that even ancient man understood how to make glass.
How is Glass Manufactured in Industry?
I have already provided you with a rough idea of how glass is made, but now let’s look at how glass is made in a proper industrial situation. In an industrial glass plant, sand is mixed with waste glass pieces (often collected from recycling), limestone (calcium carbonate CaCO 3 ) and soda ash (sodium carbonate Na 2 CO 3 ) before being heated in a furnace. The soda ash added to the mixture is solely for the purpose of reducing the sand’s melting point, in a bid to save energy in the manufacturing process. However, this also has an unwanted drawback—it produces a type of glass that would dissolve in water. To control against this, limestone is added to the mixture. The end product obtained from this process is technically called soda-lime-silica glass. This soda-lime-silica glass is the general-purpose glass we commonly see around us.
Tinted glass
In a bid to make different types of glass, commercial glass manufacturers often use slightly different glass manufacturing processes. This change often comes in the form of adding other chemicals. Chemicals are added with the purpose of changing the appearance or properties of the finished glass. For example, chromium- or iron-based chemicals are added to the molten sand mixture to make green-tinted glass, whereas mixing in cobalt salt produces blue glass. To make oven-proof glass, boron oxide is added to the molten mixture. Lead oxide is added to make a fine crystal glass that can be more easily cut when required.
Toughened glass
Some highly specialized and super strong variants of glass, such as bullet-proof or tempered glass, is made through a different manufacturing process. Sandwiching multiple layers of glass and plastic is done to make bulletproof glass. Toughened or tempered glass used in car windshields and automobiles is usually made by cooling molten glass very rapidly to make it much harder.
Bulletproof glass demonstration, New York. (Photo Credit : LHcheM/Wikimedia Commons)
There are innumerable places where you’ll find glass—from bulbs tucked in thermometers and the fiberglass hulls of boats, to the sandpaper (also called glasspaper) we use for decorating and the strain gauges that warn us when buildings are cracking. Glass is clear, clean, cheap, unreactive, strong and endlessly useful. What more do you want? Glass is one of those magic materials that we absolutely take for granted, but it unrelentingly serves the purpose it is intended for, provided you use it with care!
2. Write sentences from the words in brackets ( ). All the sentences are present. a. (this room / clean / every day)
b. (how often / the room clean?)
c. (glass / make / from sand)
d. (stamps / sell / in a post office)
e. (football / play / in most countries)
f. (this machine / not / use / very often)
g. (what language / speak / in Ethiopia?)
h. (what / this machine / use / for?)
This room is cleaned every day .
b. (how often \/ the room clean?)
How oft en is the room cleaned ?
c. (glass \/ make \/ from sand)
Glass is made from sand .
d. (stamps \/ sell \/ in a post office)
Stamps are sold in a post off ice .
e. (football \/ play \/ in most countries)
Foot ball is playe d in mos t coun tries .
f. (this machine \/ not \/ use \/ very often)
This machine is not used very often .
g. (what language \/ speak \/ in Ethiopia?)
What langua ge is spoken in Ethiopia ?
h. (what \/ this machine \/ use \/ for?)
What is this machi ne use d for ? «>,<"id":38542516,"content":"
a) This room is cleaned every day.
b) How often the room is cleaned?
c) Glass is made from sand.
d) Stamps are sold in a post office.
e) Football is played in most countries.
f) This machine isn’t used very often.
g) What language is spoked in Ethiopia?
h) What is this machine used for?
Passive Voice
A voz passiva \u00e9 usada quando queremos expressar que pessoa\/objeto\/animal est\u00e1 sofrendo uma a\u00e7\u00e3o, ao inv\u00e9s de realiz\u00e1-la. O discurso direto (algu\u00e9m fazendo algo) se transforma em discurso indireto (algu\u00e9m sofrendo algo). \u00a0
a) This room is cleaned every day.
b) How often the room is cleaned?
c) Glass is made from sand.
d) Stamps are sold in a post office.
e) Football is played in most countries.
f) This machine isn’t used very often.
g) What language is spoked in Ethiopia?
h) What is this machine used for?
Passive Voice
A voz passiva é usada quando queremos expressar que pessoa/objeto/animal está sofrendo uma ação, ao invés de realizá-la. O discurso direto (alguém fazendo algo) se transforma em discurso indireto (alguém sofrendo algo).
Ex. na voz ativa:
Ex. na voz passiva:
Exemplo desta frase em inglês:
Note que é necessário prestar atenção no tempo verbal, porque o passive voice segue uma estrutura diferente, dependendo dele.
Para saber mais sobre passive voice, acesse: brainly.com.br/tarefa/49751251
a. (this room / clean / every day)
This room is cleaned every day.
b. (how often / the room clean?)
How often is the room cleaned?
c. (glass / make / from sand)
Glass is made from sand.
d. (stamps / sell / in a post office)
Stamps are sold in a post office.
e. (football / play / in most countries)
Football is played in most countries.
f. (this machine / not / use / very often)
This machine is not used very often.
g. (what language / speak / in Ethiopia?)
What language is spoken in Ethiopia?
h. (what / this machine / use / for?)
What is this machine used for?
Can You Use River Sand to Make Glass? Good Idea or Epic Fail?
Glass is so commonplace in the modern world that it is often taken for granted. For those of us who enjoy working with glass though, it becomes an obsession.
The most dedicated and motivated among us sometimes consider bringing their hobby to the next level by making their glass themselves from locally sourced river sand, but is that really a good idea?
Can you use river sand to make glass? River sand can be heated to the point that it becomes glass, but unprocessed, natural river sand may not have ideal percentages of silica and often contains impurities that will negatively affect the finished glass in terms of color, clarity, and workability.
The sand in and around river beds is abundant, and depending on the type and purity of the sand, it may be just what you were looking for if you were considering melting sand down into glass yourself.
Unfortunately, not all river sand will produce desirable results. Let’s take a closer look at whether or not using river sand to make glass is actually a good idea.
Making Glass
Most people know that sand is involved when making glass, but many are unaware of the actual process and incredible heat involved.
If you’re considering making your own glass from river sand, it’s important to have a good grasp of the fundamentals first, or you will be setting yourself up for failure before you even begin.
The Basics
So, how is glass made?
On its own, sand will begin to melt shortly after reaching temperatures slightly over 3,000℉.
That is quite a bit of heat, and many kilns aren’t quite up to the task.
However, flux additives such as potash, sodium carbonate, or sodium oxide will reduce the melting point significantly.
A downside of using a flux additive is that it makes the glass water permeable and eventually water soluble – not exactly ideal for glass.
A stabilizer such as lime must be added to counteract the negative effects of the flux and add solid properties and durability to the glass.
Generally, the final mixture would consist of about 60% sand and 40% additives.
The mixture is placed into a heat-proof crucible, and into the furnace or kiln it goes until it becomes liquid glass.
The time needed for this to happen depends on the temperature of the furnace, the amount of mix being melted, and the exact ratio of sand to additives.
Once the sand has become molten glass, it may be gathered on the end of a metal tube and blown (you can read more about glass blowing here ) or shaped and molded according to the artist’s vision.
Will River Sand Work?
Well, maybe, but maybe not. The answer here really depends on several factors.
Broadly speaking, some river sand can be successfully used to make molten glass, but the quality will likely be pretty poor due to the presence of impurities.
Unless you already have the ideal setup in place and really know what you are doing, the odds are rather high that you’ll be disappointed with the results.
However, it can be done in certain circumstances.
Let’s take a look at each of the factors that determine whether or not river sand should be used.
Composition
Not every source of sand is ideal for glass making.
Some river sand has enough silica content (greater than 95% silica) to be considered true silica sand (also known as quartz sand).
For example, sand along portions of the Mississippi River contains high levels of silica, as do some beaches in Florida, such as those in Siesta Key.
Minnesota also is known for its quartz.
Considering that quartz is one of the most common minerals found in the earth’s surface, your local rivers may be a better source for silica sand than you may have realized.
The problem is ensuring that the sand consists of 95% or more pure silica (silicon dioxide).
Impurities
Even if there is enough silica present in your river sand, there may be impurities, such as clay particles, silt, shells, oil, decomposing plant and/or animal particles, and salt lurking as well.
Obviously, these will negatively impact the quality, durability, workability, and color of the glass.
The presence of minerals, metals, and metal compounds will affect the color of the resulting glass.
If you are not aware that they are present, you’ll likely be surprised by the color of your glass once it has cooled.
Tiny stones, pebbles, and bits of trash will cause problems as well if they are not thoroughly sifted out prior to firing.
In the following video, the young man attempts to make a blown-glass bottle using glass made from river sand that he harvested along the Mississippi River.
You can see for yourself what he wound up doing.
Source of the Sand
Of course, you can expect that sand that you source yourself from a local river will have impurities. That’s a given.
Some areas will be naturally purer than others, but contaminants are still likely.
GharPedia provides a list of field tests that will give you a general idea of the quality of the sand, or you can send a small sample of the sand to a testing facility to check for pureness.
For obtaining river sand, a better option may be to purchase it from a home improvement store or a local supplier.
In most cases the sand will have been washed, filtered, and kiln dried. Quality suppliers will also have the sand tested for impurities.
Legal Issues
It may be illegal for you to collect and bring home a bucket of river sand, depending on where you live.
Some states’ laws might not specifically prohibit removing sand, but others, such as Virginia, clearly do.
Check the laws pertaining to your area carefully before removing any sand, even if you think no one is watching. It’s not worth facing a hefty fine or jail time.
Problems You May Encounter Using River Sand
We’ve already discussed that impurities will likely be found in river sand that you collect yourself, but how will this directly affect your glass?
Well, the final color of the glass may have a greenish tint or other color depending on which metal compounds the sand contains.
For example, in the commercial production of colored glass, iron oxides are added to produce green or brown glass, and cobalt oxide is added to the mix to produce the widely popular deep blue glass.
Fun fact: Red glass is produced by adding gold chloride, which explains why glass of this color tends to be more expensive.
Another problem you may have with river sand glass is the inability to shape or mold it as desired. Again, this is caused by impurities.
Attempting to blow glass made with impure sand will likely prove especially difficult.
One last thing to be aware of is the size of the sand grains.
Large-grained sand will take a lot longer to melt, sometimes even days, and may not be worth the trouble.
The smaller the grains, the faster the sand will melt and become glass.
Use a Respirator
Inhaling silica dust particles can cause irreparable damage to your lungs and respiratory tract.
When using river sand to make glass, the chances of dangerous exposure to high levels of silica dust are relatively low (unless you’re crushing it down to a finer grain) but why take the risk?
Frequent exposure to the fine dust particles and the fumes generated from the melting process can cause issues such as bronchitis, asthma, chronic obstructive pulmonary disease (COPD), silicosis, and even lung cancer.
It’s better to err on the side of caution by wearing a respirator to protect yourself.
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II. Write sentences from the words in brackets ( ). All the sentences are present.
1. (this room / clean / every day) This room is cleaned every day.
2. (how often / the room / clean?) How often is the room cleaned?
3. (glass / make / from sand) Glass …………………………………………………..
4. (stamps / sell / in a post office) …………………………………………………….
5. (football / play / in most countries) ………………………………………………..
6. (this machine / not / use / very often) …………………………………………….
7. (what language / speak / in Ethiopia?) What …………………………………….?
8. (what / this machine / use / for?) …………………………………………………?
III. Write sentences from the words in brackets ( ). All the sentences are past.
1. (the room / clean / yesterday) The room was cleaned yesterday.
2. (when / the room / clean?) When was the room cleaned?
3. (this room / paint / last month) This room …………………………………………
4. (these houses / build / about 50 years ago) ……………………………………….
5. (Ann`s bicycle / steal / last week) …………………………………………………
6. (three people / injure / in the accident) …………………………………………….
7. (when / this church / build?) When ………………………………………………?
10. (anybody / injure / in the accident?) …………………………………………….
11. (why / the letter / send / to the wrong address?) ………………………………….?
Vocabulary and Speech Exercises
I. Fill the gaps with prepositions; read and translate the text.
There is a total … 650 judges … Great Britain, although their duties vary … the different legal systems … England and Wales, Scotland and Northern Ireland. Only about 3 per cent … judges are women. The majority are upper class, white males with an average age … 60, often educated … public schools and Oxford or Cambridge University. The Lord Chancellor, the highest judge … the land, which is also the head … the House of Lords, chooses new judges … the advice …. Other judges and important barristers, but nobody knows exactly how the process works or why decisions are taken.
Judges are usually men have been barristers … at least ten years.
II. Fill the gaps with the words from the box, read and translate the text.
Undergraduates, lecture, get, pass, tuition, courses (3), degree, lectures, enter, subjects, grant, note, graduate, postgraduate, lecturers, postgraduates.
If you want to … university, you must first … examinations that most students take at the age of eighteen (called A-level). Most students take three A-levels (three examinations in three different …) and they must do well in order to … a place at university because the places are limited. At the moment, about 30 % of young adults go to university in Britain.
If you get a place at university, the … is free, and some students also receive a …as well. Most university … last three years, some … last four years, and one or two … e.g. medicine, may be even longer. During this period students can say they are doing/studying law, or doing/studying for a … in law, for example.
At schools you have teachers and lessons at university you have … and …. When a lecturer gives a …, the students listen and take …, but do not usually say much, except to ask occasional questions.
Read and translate this text
SOLICITORS AND BARRISTERS
England is almost unique in having two different kinds of lawyers, with separate jobs in the legal system. The two kinds of lawyers are solicitors and barristers.
If a person has a legal problem, he will go and see a solicitor. Almost every town will have at least one. In fact there are at least 50,000 solicitors in Britain, and the number is increasing.
Many problems are dealt with exclusively by a solicitor. For instance, the solicitor deals with petty crimes and some matrimonial matters in Magistrates Courts, the lowest Courts. He prepares the case and the evidence. He actually speaks in Court for you.
In a civil action he can speak in the County Court, when the case is one of divorce or recovering some debts. In the County Court the solicitor wear a black gown over his ordinary clothes.
A solicitor also deals with matters outside Court. He does the legal work involved in buying a house, for instance. He writes legal letters for you and carries on legal arguments outside Court. If you want to make a will the best man to advise you is a solicitor.
To qualify as a solicitors, a young man or a woman joins a solicitor as a “clerk” and works for him whilst studying part time for the “Law Society” exams. Interestingly enough, it is not necessary for you to go to university. When you have passed all the necessary exams, you can “practice”, which means you can start business on your own.
Barristers are different from solicitors. Barristers are experts in the interpretation of the Law. They are called in to advise on really difficult points. The barrister is also an expert on advocacy (the art of presenting cases in Court). Indeed, if you desire representation in any Court except the Magistrates Court, you must have a barrister, with one or two exceptions.
Barristers are rather remote figures. If you need one, for instance, you never see him without your solicitor being with him. Barristers do not have public offices in any street. They work in what are known as chambers, often in London. They all belong to institutions called Inns of Court, which are ancient organizations rather like exclusive clubs. In many ways the remoteness they have and the job they do are medieval in conceptions.
To qualify as a barrister you have to take the examinations of the Bar Council. These are different from solicitors examinations. There are over 5,000 barristers in England. A good one can earn 30,000 pounds a year. Only barristers can become judges in an English Court above a Magistrates Court.
UNIT 8
CRIME AND SOCIETY
Scan the text.
The police are the public servants whose duty is to detect and prevent crime. If the police believe that they have enough evidence to show that a person has committed a criminal offence, they will make an arrest. The accused person will be prosecuted and taken to court where there will be a trial to determine whether the person is innocent or guilty. The accused will be found guilty only if the people trying him or her are convinced beyond reasonable doubt that they committed the crime with which they are charged. The law under which the person is charged will define precisely what the prosecution must prove in order for the accused person to be convicted. For example if someone is charged with murder, the prosecution fails to prove the intention and shows only that the accused was very careless (“negligent”) they cannot be convicted of murder, although they might be convicted of manslaughter.
Similarly, in order for someone to be convicted of theft, it has to be proved against them beyond all reasonable doubt that they dishonestly took the property of another with the intention of permanently depriving the other of it. If it is proved that the accused merely borrowed the property and intended to return it, they should not be convicted of theft.
Thus, in general, criminal offences have two elements: a physical element (for example, the act of killing a person, or the taking of property), and a mental element (the intention to kill, or the dishonest intention permanently to deprive). The prosecution must therefore prove not only that the accused did the unlawful physical act, but also what their intention was, for it is generally considered unfair and in the United States unconstitutional, to convict someone of a criminal offence which they did not mean to commit but committed only innocently or by accident.
To be effective punishment must be acceptable to the society in which it is used. If the majority of people think it is cruel or unreasonable, they will not cooperate in bringing people to justice or support the police. Similarly it must be carried out fairly, so that the same punishment is seen to be inflicted in the same circumstances. In Japan and USA the constitution forbids “cruel and unusual punishment”. This prevents the use of penalties much harsher than the harm caused by the crime. Punishment must be carried out quickly if it is to reform or deter. It will cease to be associated with the crime if delayed.
According to the theories of punishment there are three models of punishment – retribution, rehabilitation, and deterrence. Retribution is based on the premise that the offender is a reasonable person freely made the decision to violate the law, so the wrongdoer should be punished in such a way that the punishment fits the crime. Rehabilitation is the notion that punishment should rehabilitate or reform the behavior of offenders so that they will become law-abiders rather than lawbreakers. Deterrence refers both to discouraging this particular offender from further illegal acts and to deterring others from criminal activity.