Warm up idea for adults: what is this?

A good dynamic to work with adults or older teenagers is to show different objects, animals, people, etc in a close-up shot and ask learners to guess what it is. If teachers wich to adopt a more scientific theme, they might think is more instigating to show pictures of different molecules and space images to entice students.

 

Cafeine molecule

                                                                         Stardust