The most common and most likely answer to this crossword clue is the 6 letter word SAMPLE
I've seen this crossword clue in The Times
S
A
M
P
L
E
More clues leading to the result SAMPLE
- Plenty to follow small specimen
- Demonstration somewhere in Greater Manchester includes local politician
- Small enough to try
- Survey quantity both small and large?
- First of sips, enough to taste
- Small enough specimen
- Society very large for instance
- Specimen supplied by son, more than enough
- Try politician in North West town
- Sperm donor’s thing to be small and rather bulky?
Buddy explains!

The straight part
We know that "Demonstration" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case demonstration = sample.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SAMPLE mean?
SAMPLE noun- A part or snippet of something taken or presented for inspection, or shown as evidence of the quality of the whole; a specimen.
- A subset of a population selected for measurement, observation or questioning, to provide statistical information about the population.
- A small quantity of food for tasting, typically given away for free.
- A small piece of some goods, for determining quality, colour, etc., typically given away for free.
- Gratuitous borrowing of easily recognised phases (or moments) from other music (or movies) in a recording.
- Example; pattern.
- To take or to test a sample or samples of.
- To reduce a continuous signal (such as a sound wave) to a discrete signal.
- To reuse a portion of (an existing sound recording) in a new piece of music.
- To make or show something similar to a sample.