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Physics

Is your website flickering?

Alexis Wilke's picture
Height of Operative Control Relative to a Vertical Plane

Today I was visiting the American Cancer Society when I stumble upon a strange sentence... Now I'll have to think about means to inform Snap! users whenever they are creating a page that could be affected.

The sentence goes like this:

Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz.

The figure to the right shows the accessibility of an handicapped person in a wheelchair.
Click on the picture to see the full figure from
Section 508 paragraph 1194.41.

Why are pictures from my movies looking so bad?

Alexis Wilke's picture

Video versus Photo

Have you ever tried to film a movie to later find out that you just couldn't use a single one of the many images as a nice photo on your Snap! Website?

Newton's Cradle showing the law of conservation of momentum.
Newton's Cradle

If you still wonder why the quality of a video image is so poor in comparison to just taking a still picture, then this article will most certainly help you understand the several reason behind the problem.

First of all, know that there are now many different types of video cameras available and each runs with a different software. Each brand created the best version ever, yet it really results in each brand having a set of features better adapted to a specific situation. This being said, it actually would not be possible to just merge all the software and get the best of all worlds! The same properties as found in physics apply here: when you gain on one side, another has to give way.

What is RAM? You need it so your computer runs

Alexis Wilke's picture

Memory DrawersAs I mentioned in an early post, I will also teach my readers how computers work. Remember that Snap! Websites needs all of that to work... and I hope to make the information accessible to everyone. Don't forget that you can hover your mouse over abbreviations and acronyms to get their full definition. There is also a link to my Glossary at the bottom of each post.

All computers require some kind of memory to run. A computer that always does exactly the same task may use what we call ROM or Read-Only Memory, although the processor will still make use of RAM or Random Access Memory for its registers. In other words, all computers need to have a certain amount of RAM in order to function.

So, what is RAM?

Abstraction

Programmers view memory in an abstract way: a set of drawers where they can store a number from 0 to 255.