Expository text - How does instant photography work?

When I was a kid, my parents used to have a polaroid camera. They took pictures and shortly afterwards the image magically appeared. For those of you who, very much like me, have always wondered how this was even possible, here is the explanation.

Instant film or film for polaroid cameras is very similar to regular film. The main difference between the two of them is the developing process. While a regular film has to be developed externally, in a dark room, the instant film already has all the needed chemicals in its layers. Therefore, the picture develops as soon as it's been taken.

The film itself comprises of several different layers, as you can see in the image.

When a photograph is taken, the silver atoms on the film react with the light photons and create an image. In order to get a real picture, it needs to be developed. For this, rollers inside the instant camera spread the reagent layer, which is made of opacifiers (light-blockers), alkali (acid neutralizers), white pigment and other elements.

Underneath the reagent layer, there are three different light sensitive layers (blue, green and red). Under each of them lies a dye developer in its complementary color (yellow, magenta and cyan respectively). When a certain color of light reaches its sensitive layer, the opacifiers block the dye developer right underneath it. The other two developers can move up to the image layer.

This means that if blue light hits the blue sensitive layer, the yellow dye developer gets blocked. Therefore, only magenta and cyan reach the image layer, creating the color blue.

If you have ever seen an instant photograph develop, you know that it is usually greyish at first and only slowly becomes visible. This is due to the opacifiers. The reagent chemicals not only work their way down through the dye developers but also up through the image, timing and acid layer. The picture will stay greyish until the opacifiers and the alkali reach the acid layer where they react. This reaction makes the opacifiers become invisible and the picture visible. The timing layer slows the reagent chemicals down, leaving the picture underneath enough time to develop.

And voila, that is how instant films work. You see, it, unfortunately, has nothing to do with magic after all. 

Camera Lucida - How helpful were the instructions?

Tim Hunkin’s instructions on how to make a camera lucida appear to be easy to follow due to the pictures and the text accompanying them. However, the set of instructions turns out to be rather confusing when examined more closely. Firstly, the instructions given are incomplete. For example, the instructions mention a hole to look through although said hole was never mentioned before. Similarly, the installation of the reflecting plastic plate is missing. The author probably left these steps out purposely as they seemed obvious to him. To someone who has never  built a camera lucida before, however, these steps are essential. It would also have been more helpful to number the steps, even if the text is very short. Another confusing aspect that the reader constantly has to jump between the text and the pictures. Neither text nor pictures are sufficient on their own to explain how the camera is built without causing utter confusion. Overall, the text itself is not badly written. It is concise and understandable, but the fact that it is only partially complete makes the instructions rather difficult to follow.

Group paragraph

http://daweiss.blogspot.co.at/2014/01/group-paragraph.html

Sweden

http://daweiss.blogspot.co.at/2014/01/essay-versions-textkompetenz.html

EU individual paragraph

Brainstorming:

• 24 languages
• known languages, such as English, German,...
• less known languages, like Maltese,...
• language families and subfamilies
• related, yet different

First Draft:

What interested me most about the EU and this week‘s topics were the different languages. Altogether, 24 different languages can be found in the EU. They range from the most commonly known languages, such as English, German or French, to languages less known or obviously related to the EU, e.g. Lithuanian or Maltese. Every language belongs to a language family and in the EU, the present language families are the Germanic, the Romance, the Slavic, the Baltic, the Celtic, the Uralic and the Afroasiatic one. Languages deriving from the same language family share certain similarities. A good example for this is the Romance language family. Some of its members are Italian, Spanish or French and therefor they sound very similar. Having one of those languages as your mother tongue makes it fairly easy to learn another language from the Romance language family. The fact that all 24 languages, as different as they might be, can exist along side each other and the EU still manages to work is one of the things why I consider this topics, languages in the EU, to be highly interesting.

Student ideas:

• topic and concluding sentence go well together
• leave out the "languages in the EU" in the concluding sentence
• therefore with an "e"

Second Draft:

What interested me most about the EU and this week's topics were the different languages. Altogether, 24 different languages can be found in the EU. They range from the most commonly known languages, such as English, German or French, to languages less known or less obviously related to the EU, e.g. Lithuanian or Maltese. Every language belongs to a language family and in the EU, the present language families are the Germanic, the Romance, the Slavic, the Baltic, the Celtic, the Uralic and the Afroasiatic one. Languages deriving from the same language family share certain similarities. A good example for this is the Romance language family. Some of its members are Italian, Spanish or French and therefore they sound very similar. Having one of those languages as your mother tongue makes it fairly easy to learn another language from the Romance language family. The fact that all 24 languages, as different as they might be, can exist along side each other and the EU still manages to work is one of the things why I consider this topic to be highly interesting.

Student feedback:

• Too many repetitions - especially language and language family

Third Draft:

What interested me most about the EU and this week's topics were the different languages. Altogether, 24 different kinds can be found in the EU. They range from the most commonly known languages, such as English, German or French, to the ones less known or less obviously related to the EU, e.g. Lithuanian or Maltese. Each language belongs to a family and in the EU, the present language families are the Germanic, the Romance, the Slavic, the Baltic, the Celtic, the Uralic and even the Afroasiatic one. Languages deriving from the same family share certain similarities. An excellent example for this is the Romance language family. Some of its members are Italian, Spanish or French and they sound very similar. Having one of those languages as your mother tongue makes it fairly easy to learn another Romance language. The fact that all 24 languages, as different as they might be, can exist along side each other and the EU still manages to work is one of the things why I consider this topic to be highly interesting.

Final Draft:

What interested me most about this week's EU topics were the different languages with their different origins as well as their similarities. Altogether, 24 different languages can be found in the EU. They range from the most commonly known languages, such as English, German or French, to lesser known ones, e.g. Lithuanian or Maltese. Each language belongs to a family and in the EU, the language families present are the Germanic, the Romance, the Slavic, the Baltic, the Celtic, the Uralic and even the Afroasiatic. Languages deriving from the same family share certain similarities. An excellent example for this is the Romance language family. Some of its members are the languages Italian, Spanish or French and they sound very similar. Having one of those languages as your mother tongue makes it fairly easy to learn another Romance language. The fact that all 24 languages, as different as they might be, can exist alongside each other with the EU still functioning is one of the reasons why I consider this topic to be highly interesting.