Geographers often contrast locations and situations, such as the differences between MEDC and LEDC environments, or between climate zones or highland / lowland.
It's perfectly possible to do this without a single diagram or photograph if you subscribe only to the 1890's techniques of statistics and lists to memorize and regurgitate, but I hope there are very few geographers left who are so dull in the classroom!
Using selections of contrasting photographs allows the teacher to present specific information and enables the pupils to learn from their own observations. The technique is as well suited to small groups as it is to individuals, is easily adapted to the most advanced pupil and the one struggling most with the topic, and can be easily extended into homework or future lesson work.
A lesson based on contrasting images requires an enthusiastic teacher, clear objectives and outcomes, and the right images. The downside of such lessons is that they can lose their momentum if the teacher doesn't control them carefully and keep the pace going throughout the activity, so planning, as always, is of key importance.
Imagine a lesson on rivers - investigating a river from youth through to old age, or from source to mouth. We talk about gradients, velocity, depth, capacity and competence first, then hand out a good selection of appropriate photographs, cross-sections, friction and velocity data etc. Ideas to take this forward could include:
Developing their analytical skills and ability to recognize features by simply describing what they can see;
Annotating the images, adding direction of flow, features such as meanders, riffles, or tributaries;
Describing their images to the rest of the class and letting their peers guess what type of river or feature they are looking at;
Placing their images along a map of an imaginary river, perhaps adding extra detail of their own creation around the fixed points given by the images;
Matching the cross sections or friction / velocity information to the images;
Creating 'odd one out' sets where all but one image in a set have a common theme. The rest of the class then guess which image is the odd one out, and try to explain why. For example they might present four images of erosional features and one of an obstruction in a river.
Describe what it would be like to be next to / in the images. For example what would the ground be like, are there likely to be settlements near by, is the water clean or polluted, would it be a 'nice' place to be (environmental quality)?
Younger pupils can relate the photographs to easier concepts such as near the coast, in farmland, up a mountain, good for fishing, excellent for ducks etc. All these observations can lead to further study such as 'how do you know it's farmland, what clues told you that, would you like to live there, and why?
So, next time you think about using a 5 min clip of video, carefully cut to avoid the other 35 minutes you don't need, consider using a few selected still images and a lesson based on investigation and using contrasting images