As a means of communicating science, chalk talks can be an extremely effective way to engage the audience. These days such presentations have become part and parcel of the interview process of those seeking academic jobs in the life sciences. As much as I love such chalk talks, that's not what I will discuss today. Rather, I want to bring to your attention a historic chalk talk or, better said, a talk about chalk. Let me begin with the question: What is chalk? First answer is that most "blackboard chalk" (the multi-colored sticks we use when giving chalks talks! ) is not really chalk, it's gypsum. "Real" chalk is a soft porous rock made of CaCO3 (calcite). And, strikingly, chalk deposits are by and large made up coccoliths, the microscopic shells of coccolithophores, unicellular algal members of phytoplankton (see also a piece in this blog ). That such massive rock formations result from microbial growth and death is common knowledge today but it was not so 150 years ago. That is what makes this particular talk about chalk so remarkable. I'm talking about the lecture "On a Piece of Chalk" that Thomas Henry Huxley (a.k.a. "Darwin's Bulldog" for being such a strong advocate of evolution ) gave in 1868 at a meeting of the British Association for the Advancement of Science in Norwich. I thank Rich Lenski for alerting me to the existence of this lecture some five years ago, after I gave a lecture at Michigan State presenting some our work on coccolithophores no less! But I don't feel too bad about having been ignorant of the existence of this wonderful essay. At a recent chalk talk that I gave, I polled the audience. Only one of the forty or so "microbial scientists" in attendance had read it. Hopefully, many more will read it in the future if we pass the word.
On a Piece of Chalk cover image Source; Thomas Henry Huxley photograph Source
The persuasive nature of Huxley's narrative is a delight. While it is nowhere explicitly stated, I can imagine him with a piece of chalk in his hand, holding it up and starting: "If a well were sunk at our feet in the midst of the city of Norwich, the diggers would very soon find themselves at work in that white substance almost too soft to be called rock, with which we are all familiar as chalk." He sets out to place the very familiar writing tool – a piece of chalk – in the context of the Earth. Quickly, he moves from the rock underneath Norwich to the rock underlying all of Europe, the Middle East and Central Asia. It's all chalk! Then come two shockers.
First, he states that while made of a simple chemical, CaCO3, microscopic analyses had shown him that chalk is made up of the calcareous skeletons of tiny ocean dwellers. Coccoliths he calls them, that is "round rocks." Second, he reveals that in the process of mapping the North Atlantic Ocean floor in preparation for laying down of the first transatlantic cable, his friend Captain Dayman has brought up samples from the sea floor. Everywhere between Ireland and Newfoundland, the mud samples, when dried out, are chalk. And when analyzed, the mud samples contain the same calcareous skeletons and also some of their living carriers.
Many conclusions that were utterly unexpected at the time emerge from these findings. Norwich, as well as the vast expanse of land reaching into Central Asia, was once the bottom of an ocean. The process of chalk formation at the bottom of the ocean is slow and the chalk deposits are thousands of feet thick. The Earth is ancient and yet it is slowly but continually morphing. And most appealing to me, microbes shape the Earth.
The essay goes on to describe the fossils of large creatures embedded in the chalk and in doing so points clearly at the slow but undeniable pace of evolution. But, no more spoilers, I hope you will enjoy reading it in its entirety (for your convenience, a link to the PDF file is provided below ). What a wonderful example of effective communication of science! I find it very fitting that the most abundant coccolithophore in present day oceans, Emiliania huxleyi, is named in honor of the essay's author.
Download: On a Piece of Chalk (PDF)
The survey on the production of chalk out of sea shells was designed to bring forth quality dustless and long lasting chalk to compare with the standard bing commercialised chalks if there are any. which was sold in the market. The chalk out of sea shells is for local or non-local used for schools or any educational facets or even at place which can be formed into different sizes and colourss harmonizing to your will. We. the research workers. used the sea shells to recycle and transformed it into a utile merchandise that will be used in our developing community. The production of this artefact that has been created by us purely followed the processs. First. roll up sea shells from the sea shore. Then. boil it until it opens and being crushed into pulverization and becomes ready to be processed and made to different figures. Therefore. the production of the merchandise was accomplished and tested on its qualityand strength. Datas on the successful merchandise were tested and was finished accurately. Consequences showed that the said finished merchandise. made from sea shells. is comparable in footings of visual aspect and quality.
More people used to roll up seashells for merriment and for past clip. They made ornaments. jewelleries and even accoutrements for a doll out of it. But don’t you know that aside from those things. seashell can besides do into a much utile thing. We are cognizant that instruction is the most powerful key for us to win. And to back up this. we need some installations and stuffs for us to do it easier and clearer. Of class. we know that we already have some modernized equipments. but still. for those hopeless states and people who besides want to be sent in school. even a worst installation affairs. We already have whiteboards that merely need markers and projectors as the most modernised. But still. the beginning of those is merely a simple chalkboard and a piece of chalk. So. we. the research workers. made some tests and mistakes from different natural stuffs to be made into a more lasting chalk. Until to that minute that we have agreed and wining one of our tests. to do a chalk out of seashells.
Statement of the Problem
The monetary value of about all commercialized or local merchandises continuously increasing. And this chalk out of seashells is a large facet to be considered in schooling. Some of the schools don’t have adequate support from authorities and this thing brings troubles for us pupils. Significance of the Study
This survey opens another manner for us people to be able to salvage and do chalks that is much lasting with durable usage that will take portion in our survey. The survey was conducted as a redress for the common job of disbursement much in. And it besides helps us to derive money when you make this as your concern matter. We can besides do some natural stuffs that we thought to be useless. transformed into a much utile and improved thing.
Scope and Restriction
This survey is focused on planing and bring forthing alternate chalks. It besides deals with the appraisal of its existent advantages as compared to some commercialized one. The qualities and measures informations obtained in the testing of the merchandise against the control were limited to 3 trials merely. Related Literature
A seashell is the common name for a difficult. protective outer bed. a shell. or in some instances a “test” . that was created by a sea animal. a marine being. The shell is portion of the organic structure of a marine animate being. in most instances the exoskeleton. normally that of an animate being without a anchor. an invertebrate. The word seashell is frequently used to mention merely to the shells of Marine molluscs. mollusc shells. but it can besides be used to intend the shells of a broad assortment of marine animate beings from different phyla.
For helpful introductory articles. see marine invertebrate sand Marine biological science. Seashells are normally found in beach impetus. natural debris deposited along strandlines on beaches by the moving ridges and the tides. Shells are really frequently washed up onto a beach empty and clean. the carnal holding already died. and the soft parts holding rotted off or holding been eaten by either marauders or scavengers. Empty seashells are frequently found by beachcombers. and roll uping these shells is a harmless avocation or survey. However. the bulk of seashells which are offered for sale commercially have been collected alive ( frequently in majority ) and so killed and cleaned. specifically for the commercial trade. This type of development can sometimes hold a strong negative impact on the distribution of rarer species. and on local ecosystems.
A. Equipment and Materials
? Mortar and pestle
? Oven wassailer
1. Roll up sea shells from the sea shore or left-over shell commissariats. and manioc. 2. Pulverized the shells until it becomes all right as pulverization and put aside in a container. 3. Grate the manioc and squash its juice utilizing fabrics. Separate the liquid from itsresidue. 4. Blend the residue of the extracted manioc and the powdered seashells. Add a smallamount of H2O at the right ratio of the measure of the mixture. 5. Model the mixture into different forms and sizes harmonizing to your desire.
6. Topographic point it under the Sun and delay until it dries up and is ready to be used.
RESULTS AND DISCUSSIONS
Table1. Physical Characteristics of the Chalk made from seashells.
Physical Characteristics| Description| | Commercial| Experimental| HARDNESS| HARD| SOFT| TEXTURE| ROUGH| ROUGH|
Table 1 shows the Physical features of the experimental and commercial chalk. It shows that they have different features in footings of hardness but are bothrough in footings of its texture.
The research was designed by oppressing the seashells. which is the chief beginning of the merchandise. and which it can be a utile and eco-friendly merchandise and can lend magnificently to our sobbing community. Through difficult research. we. the research workers studied the features of the chief beginning. which is seashell. and we analyzed that it can be a great specimen in our investigatory undertaking. We have done several experiments which lead the research workers into a winning stoping in the said undertaking. Decision
On the experiment conducted to bring forth a all right merchandise from seashell. we. the research workers discovered the features of the seashells which has specific belongingss and constructions. We discovered that it is on of the stepping rocks of the success of the merchandise in which it is commercially comparable to any commercial merchandises that are the same with us. if there are any. in footings of quality and lastingness.
Through hard. decisive. several experiments. the research workers have conquered an astonishing merchandise that has a good quality. We extremely recommend utilizing our ain original finished merchandise. made from seashells. because aside from its bargain rate. it is besides easier to bring forth. eco-friendly. reclaimable and has the possible to do our survey easier and clearer.
1. World Wide Web. Google. com. pH
2. World Wide Web. dictionary. mention. com
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