These suppliers below sell and deliver liquid nitrogen. Most of them will even rent or sell you a Dewar. You do not need a special licence or qualification to buy liquid nitrogen but you should definitely learn about all the hazards and complete a thorough risk assessment before performing any demonstrations with it.
And here’s a link to an online retailer selling the Bodum double walled coffee plunger flask I use in my presentations.
This blog was… how do you say it? Relevant!! Finally I have found
something that helped me. Kudos!
Dear Antutu… my apologies for the loooooooong delay replying to your email. This is MUSIC TO MY EYES!!! I hope you have been keeping well these past four years 😉