He has sportingly agreed to help me with a short demonstration.

Now I don't want any of you youngsters to worry.

You'll still have your potions master when I'm through with him. Never fear.

One, two, three.

Expelliarmus.

Do you think he's alright? Who cares!

An excellent idea to show them that Professor Snape,

but if you don't mind me saying it was pretty obvious what you're about to do

and if I had wanted to stop you it would have been only too easy.

Perhaps it would be prudent to first teach the students to block unfriendly spells professor.

An excellent suggestion Professor Snape.

Let's have a volunteer pair. Potter! Weasley! How about you?

Weasley's wand causes devastation with the simplest spells. We'll be sending Potter to the hospital wing in a matchbox.

Might I suggest someone from my own house? Malfoy?

Good luck Potter. Thank you sir.

Wands at the ready.

Scared Potter? You wish!