Need help writing a conclusion to my oral report (for chem). Would appreciate help or even a proofread?

This is my oral report on nanotechnology (specifically, the nanoparticles in sunscreen). I’ve put astericks around the section I’m not happy with. I don’t like that part, because it’s too vague and I took too much from my book, but molecular manufacturing is incredibly hard to define. Maybe someone here could help with that?
Otherwise, I’d really appreciate proofreading (British English) or help with writing a conclusion.

Thank you so much.

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Nanotechnology is a branch of engineering concerned with the development of technology at the atomic, molecular and macromolecular range – that is, 1 to 100 nanometers.
?Though you may not have heard of it before, a nanometer is simply a form of measurement. It is precisely 1 billionth of a metre, and we use it to measure very small things. An atom is about 0.1 nanometers in diameter, and molecules range from about 0.15 nanometers in diameter to visible, so-called, macromolecules. Bacteria is substantially larger in size, at about 500 to 5000 nanometers, and viruses, the smallest “living” things, range only 10 to 50 nanometers.

To help you understand this concept better, let me introduce the Buckminsterfullerene or C-60 “buckyball” molecule. The buckyball is a spherical-shape molecule which, in this case, contains 60 carbon atoms. The carbon atoms are bonded to form stable hexagonal and pentagonal rings, linked together in a pattern identical to a football’s patches. A buckyball is 0.7 nanometers in diameter.

Now visualise an actual football, which is roughly 22 cm in diameter. The Earth is 100 million times larger than that figurative football which, in turn, is 100 million times larger than a C-60 buckyball. So, you get the idea.

To summarise, nanotechnology is the study and utilisation of very small things.

But why is it important?

The answer is “molecular manufacturing”.

As we know, manufactured products are made from atoms and the properties of these products depend on how their atoms are arranged. But today’s manufacturing techniques are very crude at the molecular level.
?It’s like trying to build LEGO with boxing gloves on – you can’t really piece the blocks together. At best, you can pile them up and make something resembling a cubist anthill.

And this is where nanotechnology comes in:

***Molecular manufacturing is the engineering of tiny machines, designed to construct objects by manipulating atoms or molecules to make “complete and highly advanced products”.***

It’s not LEGO but, through molecular manufacturing, we could be able to piece together atoms – the fundamental building blocks of life.

The applications of nanotechnology are endless. It has the potential to build cleaner, safer and longer-lasting products, for communication, medicine, transportation, industry, agriculture and home.

And that’s what I’ll be talking about today – a way in which nanotechnology has already entered our day-to-day lives.

Sunscreen.

I’m sure you all know how to slip-slop-slap, but what about the science behind sun protection?

Zinc oxide and titanium dioxide are the main components of sunscreen. They are used, because they effectively absorb UVA – which is 98.7% of the Sun’s ultraviolet radiation to reach the Earth’s surface, and particularly harmful to skin.

The problem, however, is that these compounds also reflect UV light, which causes the sunscreen to appear white. This is because the zinc oxide and titanium dioxide particles in regular sunscreen are larger than the wavelength of visible light.

When zinc oxide and titanium dioxide are made smaller than the wavelength of visible light, they no longer reflect it, because the visible light is able to pass between the particles.

Thus, sunscreen containing zinc oxide and titanium dioxide is transparent.