Visual memory tests to use in the classroom include the face test, "Now you see it, now you don't," "What's missing" and "Who's missing." These tests are appropriate for a range of ages.
The face test is appropriate for kids from kindergarten to the 12th grade. It's an online game that randomizes a face that students must memorize. After memorizing it, the face disappears and they must put it back together again using components from a table.
"Now you see it, now you don't" is appropriate for students from kindergarten to the 6th grade. Place 10 to 20 objects on a tray, ask the students to memorize them for one minute, then cover the contents of the tray up, and send the students away to write down what they saw.
"What's missing" is appropriate for kids from kindergarten to the 6th grade. It's a variant of "Now you see it, now you don't" that allows kids to test their short term memory. Rather than asking the participants to write down the objects they saw, remove one object while they're not looking, and ask them to recall what it is. To vary the game, give the participants more time to view the objects, then gradually reduce the time. Additionally, try adding extra objects in.
"Who's missing" requires a class full of children and is suitable for kindergarten to the 6th grade. Choose two students and make one leave the room, then hide the second student. When the first student comes back into the room, ask him to identify which person is no longer there.