Thursday, 25 March 2010

Rant on Hollywood explosions!

If there's one thing that annoys me then it's the way Hollywood using exploding vehicles! They don't explode! If they exploded like Hollywood vehicles do then we wouldn't be able to drive them around safely!!

In order for an explosion to occur then all the right components must be present in as close as possible the right quantities throughout the mixture. Petrol requires air in it to burn and that is what petrol does - it burns! In a car engine the fuel and air is premixed in the correct quantities to cause the mixture to burn rapidly in the combustion chamber. Note the word 'combustion' NOT explosion. It burns so rapidly, turning a small amount of fuel and air into a very large volume of hot gas that people talk of an explosion - but it's combustion.

Now if you set fire to a petrol tank it will burn rapidly and will heat up the metal around it and could cause the tank to rupture spilling burning fuel everywhere - but it will not explode. If you do this to a larger vehicle or vessel the same thing will happen.

There is a seemingly contradictory element to this... If you weld an empty petrol tank it could very well explode! No, it may very well combust so rapidly and with so much force it will rip the tank to shreds and throw shrapnel around.  As good as an explosion anyway. This is because the tank is NOT empty but an 'empty' tank enjoys about the correct mixture of petrol vapour and air. So if you find yourself wanting to weld a petrol tank then fill it with water first!.

Tuesday, 16 March 2010

To blog or not to blog?

Today we are told that we should enjoy a 'web presence'. But why? Having read blogs by friends and not-friends I seem to see many different reasons. And why should we read them?

As I gain more experience from blogs I see several reasons for both.

Some people write blogs because they feel they should but they ponder hard about their blogging and come up with blogs that are interesting, entertaining or both. Some blog interesting ideas and some blog anything - seemingly just because they can. Some use it to seek popularity or to be reassured about their popularity. Some blog quietly while others are constantly prompting us to read their blog. It just leaves me wondering why there are so many reasons to blog. Myself, I think of blogging as a way of recording my thoughts and if they go unread then they were my thoughts anyway.

And why to read the blogs? This one is for me just as big a question. I am a slow reader and reading has always been hard work. I recently re-read a sentence 4 times before I realised the word was 'four' and not 'hour' and suddenly it made sense. When reading is like this for you you do not read everything put in front of you. If I see a friends blog post I will scan the first paragraph and if it doesn't catch me I will give up - sorry! Even if it does I may give up before the end anyway. Mary will read over my shoulder waiting for me to scroll down. I may be asked 'Did you read?' and I will ask for the gist and then maybe go to read it for myself.  Having read will I comment? Why do people comment? I will comment if I have to something to say at the time. Because I haven't commented doesn't mean I haven't read. I don't feel I need to leave my footprint in the sand just to say that I have been there. I probably enjoyed it, or I didn't finish it. I was always told ' if you don't have something to say then say nothing' and that's what I do. But I see so many comments that seem sycophantic, popularity grabbing - 'Please, I read it sir/miss!'. I am told that it's my badly developed social skills and so I apologise to all.

To all the bloggers I enjoy may I say "PLEASE keep on blogging" - for the main part I do enjoy them but don't leave my footprint to say I read them and apologise but I would miss them if they weren't there.