Camera Challenge 2 - Understanding Aperture

Now, I love those kind of photos where you can blur some bits and not the others, but to be fair it been more luck than judgement that I have achieved it previously. But thanks to this months Camera Challenge I think I have got it.
So, here are my shots on my Nikon D3200 with my bunch of volunteers.

f 5.3 Not the lowest on my camera, but fairly low!

All are focused on Mr Happychops at the front.

f10

The man in the shoulder pads is now clearer.

f20

R2D2 and even the Tennis man are nearly clear at this stage.

And then lastly at f36

They are perfectly clear here, although for this photo and the f20 I did have to use a kitchen barstool as a tripod, as any movement between the shutters closing ends up with ones like this!

Which make you think you have been drinking and gives you a headache without the alcohol!!
And then I thought I'd see what Auto gave me.

Mr Auto picked f5.3 Aperture.

This was a really good thing to fiddle about with and I think it hopefully give me some tricks to try when taking blog photos. I think writing the blog post and editing the photos has also helped me to see it clearer, all those times the teacher told me writing it out helps was right!
I'm not claiming to know the full scientific reasoning, but Katy's explanation and putting it to use, has certainly made it clearer or blurrier depending on how you look at it!!