I suspect this:
- thought-provoking from the very first sentence; asking some question that would not otherwise come to everyone’s mind immediatey;
- even though the topic needs to be pretty specific, it should still give enough room for discussion to many people about many various cases
For example, compare these versions of the very first sentence:
There is a milk sterilization method that is not thermal yet kills all bacteria.
UV-filtering of milk is the way to sterilize it without using high temperatures
I’d use the first one, as it does not answer the question immediately, yet is strong enough to let you read further. The more times you can let someone read further, the more engagement will happen - that’s my guess though.
My thinking here is that if one does not like or knows nothing about UV, he might stop reading if he is not in the mood of learning something new. So, better not to tell about UV immediately, but rather make some appetite for some new knowledge first.