Nearsightedness and how corrective lenses fix this problem

I, like many people, struggle with being nearsighted. It is very frustrating to be unable to see things without the help of corrective lenses. I have always wondered the science behind why my eyes don’t work properly, and exactly how corrective lenses fix this problem. To focus on distant objects, the eye flattens and has a shorter focal length. When a person is nearsighted, they lack the ability to do this, and a blurry image is formed in front of the retina. It is fixed by using a diverging lens, which will diverge light before it reaches the eye; this results in a clear image being formed on the retina. Life as we know would not be possible without this real-life application of Physics.

(Kaitlyn, Source)

What does an avocado seed has to do with physics?

Growing an avocado tree from seed goes viral on the Internet.  Numerous videos that document the growing plant are to be found on YouTube. The base of the method is to place the seed supported by three/four toothpicks in water.  And here is what a trained physicist's eye spots immediately: the MENISCUS.

There are two menisci (yes, this is the plural) visible in the pictures. 

• A concave meniscus occurs when the liquid is attracted to a surface of another object (adhesive forces).  In the picture, it looks like the water claims the wooden toothpick. 
• A convex meniscus occurs when the forces between liquid particles are stronger than between the particles and the surface (cohesive forces).  Here demonstrated at the surface of an avocado seed.

  

A Quick Lesson in Ancient Greek

φύσις [physis] – “nature”

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φυσική [physike] – “knowledge of nature”