7. The Little Hole In A Pen Cap
You might be wondering why there is a little hole at the tip of the cap of your pen and you might not see the importance of it or you might assume it is just a design, but it really serves a significant purpose.
Without that hole, whenever you close your pen, the air trapped in the cap and the inserting of the pen will create pressure which will push the ink out of the tip of the pen preventing it from writing and secondly, it is meant to prevent death if you accidentally swallow the cap. In case you swallow a pen cap, the hole will help you breathe easily till it is surgically removed, without it, many people would have choked on it and died.