This link uses pictures to convey the size of nanoparticles and will immediately make the concept comprehensible. http://www.azonano.com/article.aspx?ArticleID=1780
Seeing things this small requires special microscopes. Here is a link that explains.
.....using light, you can’t see things smaller than its wavelength – it just goes straight through. Visible light has wavelengths in the range of 400 nm (blue) to 700 nm (red) – so you can see things that are this size or smaller with it.
Nanoparticles are typically about 10 nm in size or so – some larger, some smaller. You can see them with various types of electron microscope – they are a lot more complicated than an optical microscope! There are some pictures of nanoparticles here:http://www.nanobeach.com/particle.php
If you would come over for tea, I have a DVD of a professor who explains this stuff, and you might also like the professor who can talk about using math to figure out knots for two hours (boring!). That is to say, the math is important to working on nano-sized things and the study of origami (study of folds) has become important to all this. To do the math, you don't have to actually see anything, but who ever thought math would and origami would be part of learning about DNA knots? I am glad I own the DVD's so I can watch them again and again because this stuff is really over my head. In watching these explanations I have become concerned that our present school system is not preparing children for the future that is now. I don't think teachers have a clue what is happening in today's science.