All 7 Uses

demonstrate
in
Harry Potter (#4) and the Goblet of Fire
(Edited)

Neville was standing alone, halfway up the passage, staring at the stone wall opposite him with the same horrified, wide-eyed look he had worn when Moody had demonstrated the Cruciatus Curse.
Chpt 14

demonstrated = shown (how something is done)
To their surprise, Professor Moody had announced that he would be putting the Imperius Curse on each of them in turn, to demonstrate its power and to see whether they could resist its effects.
Chpt 15

demonstrate = show
One Herbology lesson was enough to demonstrate this.
Chpt 18
"Roun' the middle," said Hagrid, demonstrating.
Chpt 18

demonstrating = showing (how something is done)
The Hogwarts staff, demonstrating a continued desire to impress the visitors from Beauxbatons and Durmstrang, seemed determined to show the castle at its best this Christmas.
Chpt 22

demonstrating = showing
Fleur Delacour, though she demonstrated excellent use of the Bubble-Head Charm, was attacked by grindylows as she approached her goal, and failed to retrieve her hostage.
Chpt 26 *

demonstrated = showed
I ask you to demonstrate your courage one more time.
Chpt 36

demonstrate = show

Definitions:

(1) (demonstrate as in: It demonstrates my point.)
to show
The exact meaning of this sense of demonstrate can depend upon its context. For example:
- "I will demonstrate how to throw a Frisbee." -- show how to do something
- "I will demonstrate how much quicker the new computer is than the old one." -- show how something works
- "Her questioned demonstrated that she was listening and thinking deeply about what was said." -- showed to be true or proved
(2) (demonstrate as in: demonstrate to protest)
a public display supporting a cause -- usually joining with others in a political protest
(3) (meaning too rare to warrant focus)