Yesterday we looked at encoding black & white images. Today we’re looking at using color with our images. In order to really understand color, you need to understand hexadecimal, a number system consisting of 16 distinct symbols — 0-9 and A-F — which can occur in each place value (more on this later).
For homework, please watch this video:
After you watch the video, please print out and complete Worksheet - Video Guide for “A Little Bit about Pixels” Click here to download a copy. Please bring the completed worksheet with you to class tomorrow.
Today we looked at encoding black and white images using a widget on code.org. Instead of thinking of the pixels as black & white, try to think of them as on or off. On = White Pixel, Off = Black Pixel.
For homework, please complete bubbles 2,3,4,5 & 6 on code.Org Unit 2 Lesson 3
When you abbreviate or use coded language to shorten the original text, you are “compressing text.” Computers do this too, in order to save time and space. The art and science of compression is about figuring out how to represent the SAME DATA with FEWER BITS.
What makes doing this compression hard? You can start in lots of different ways. Early choices affect later ones. Once you find one set of patterns, others emerge. There is a tipping point: the dictionary starts to get so big that you lose the benefit of having it. But then you might start re-thinking the dictionary to tweak some bits out.
Do we think that these compression amounts that we’ve found are the best? Is there a way to know what the best compression is? We don’t know! There are so many possibilities it’s hard to know- The “best” is really just the best we’ve found so far.
Compress: to decrease the number of bits used to represent a piece of information
Heuristic – a problem solving approach (algorithm) to find a satisfactory solution where finding an optimal or exact solution is impractical or impossible.
Lossless Compression – a data compression algorithm that allows the original data to be perfectly reconstructed from the compressed data
For homework, please complete questions 4-7 on Code.org
How many bits to a byte? The 8-bit byte has become the de-facto fundamental unit with which we measure the “size” of data on computers. In fact, today most computers only let you save data as combinations of whole bytes. Even if you only want to store 1 bit of information, you have to use a whole byte to do it.
In the modern world there is a lot of data around us and usually we want it transmitted over the internet. If you want to transmit a lot of data you are limited by the speed of your internet connection. Even if you have a fast Internet connection there is a physical limit to how fast you can transmit bits.
CSP Unit 2 – Digital Information
Chapter 1: Encoding and Compressing Complex Information
Lesson 1: Bytes and File Sizes
Questions 2,3,& 4
Today I assigned you a final Sandbox activity on CodeHS.com. If you need help finding it, please email me.
Remember to bring your permission slips for next week’s field trip
Test on Programming on Monday: It will cover all of Programming in Code.Org and Codehs.com
Today we finished out Programming with Java unit on CodeHS.
Here is the video on using Java to create graphics:
For homework, please complete all of the activities in Unit 3.7 on CodeHs.Com
Today we learned 2 different concepts that will combine in our final lessons on CodeHS.
The first was Variables With User Input:
The other concept was doing calculations in Java:
Please complete both of these sections for homework tonight.
Please remember to submit the Individual Written Response on turnitin.com before class on Monday.
Also, make sure you’re done with the Variables section on CodeHs.com
We’ll go over User Input on Monday.