1. What is metadata? Give an example. Metadata is the set of data that describes data. This includes file names and the datas date of creation and previous modifications.
2. What is a model? A model is a representation of a photograph using bits.
3. What's the difference between a raster image and an ASCII representation of a text document? A raster image representation of a text document would be good for seeing typefaces, colors, fonts, etc, however, if the pixels are not small enough and there are not enough of them, the text will be unreadable. An ASCII representation of a text document would be good for finding text strings, but the colors and typefaces would not exist.
4. What are filename extensions? What are they used for? Filename extensions are the three letters after the dot at the end of a filename. They are used to show how the contents are interpreted, such as .jpg, .exe, .gif, etc.
5. What is lossless representation? What is lossy representation? What are the trade-offs in using each representation? A lossless representation is a representation that renders the same exact image. A lossy representation is a representation that renders an image that is approximately the same but may have some differences that are either visible or invisible to the human eye. Lossless compression is useless for data that needs to be analyzed perfectly, such as the Zapruder film of the Kennedy assassination. Lossy compression is fine for quick images flashing onto a TV screen or for images being sent to low-quality printers.
6. What is steganography and what is it used for? Describe in your own words the steganographic algorithm used in the activity. Steganography is the art of sending secret messages in imperceptible ways. They are not suspicious looking ciphers, but instead secret messages hidden in plain sight. They may even appear innocent and be posted to public websites.
7. What would you have to do to delete a document from your computer so that it could not possibly be read by anyone else? You would have to remove it from the index and then write junk data over it in the blocks.
8. What is free and open source software? Provide an example. Open source software is software that emphasizes shared effort and peer reviewing for improved quality.
Free Response: 9. How has retouching become a controversial issue? Give an example. Retouching is altering a photo or image. It has become controversial because they are used to deceive the public. Retouching can be used to completely falsify the contents of an image. They can be used for propaganda purposes such as when Joseph Stalin retouched a photo to remove Leon Trotsky from a speech to Soviet troops held by Vladimir Lenin. It has become more and more controversial and unethical.
10. Would you rather own a camera (or camera phone) with a higher number of megapixels or lower? Explain. You would rather own a camera with a balance of megapixels. With too few, not enough will be capture in pictures. With too many, you will just have a more precise blurry picture.
11. Other than digital images, what might be an example of a computer model? Explain your answer based on the definition of a model. Blueprints for a building on a computer would be a model. It is a representation of the blueprints using bits.
12. The code that implements App Inventor is open source and its impact on education is obvious. Find another example of open source software and describe its positive impact on education, business or society. A service known as Moodle is an open source software with a positive impact on education. The software is kind of clunky but with the right use, it can be very beneficial for education.