Time needed: 45 – 90 min
Why? This method is forcing independent thinking and involving absorbed knowledge.
When? Any time if you think photos can explain more than words.
How? Just give students as homework the task to make photos in their living environment about a special topic, give them also the task to think about an explanation about the connectivity between photo and topic. Let them show their work in front of class and let them explain their reasons to take this photo and let other students also give additional comments.
Any risks? No risk, students love to show their own homework and its a very phantasy-forcing and practical work, students will like to do that.