So for example, If we did an lesson based on cartooning, where students create an illustration of a joke, they would pick the joke and their characters, maybe even based on family members. This way each project would be unique and personal. I think we can all agree that every age level can handle such a lesson.
As a teacher it helps me use a specific set of supplies. My preps are more smooth, and I don't feel crazed going from painting, to clay, to drawing, to paper mache.
But how do we do it in such a way that each grade can participate and be challenged. Differentiation is really key. Below is my unfolding project detailed HERE. You can see the elementary version on the right has been simplified to just four panels, the middle school sample has 9 panels with a riddle theme, and the right image is by a high school student who was challenged to make sure the image was cohesive when the whole work was opened to be read.
I did not do clay with the other classes when I did an illustration project. I actually did drawing projects for all classes during that week, but did very different ones with the other classes.
Alphabet or name illustrations for 1, 5, 9. Tessellations with 2, 6, 10, and grid portraits with 3, 7, 11 for example.
K-6 were on a daily rotation, so their cartoons were "one and done" affairs. We would do one-day illustration explorations for 2 weeks. Grades 7 to 12 were seen daily, so they might spend 2 weeks on a single project depending on how challenging I wanted the exploration to be.
My goal was to make sure they had fun, and I didn't go crazy flip flopping media and waste my sanity and time on prep-work. I generally like to start the year drawing and getting them use to my expectations. After a few months I allow messier media like pastels, charcoal, and non-clay sculpture. About the 3rd quarter we are painting, and by the end we'll have done clay. I go from neat to messy as they show me they can handle themselves and display appropriate studio habits. (I always do neat stuff again the last two weeks of school so I can tidy the room for the following year.)
What if you teach several classes like Sculpture, Photography, Graphic Design, etc? There again you can find themes to explore that are similar so that at least your lesson planning is easier. For example, if I am doing abstract mobile sculptures with my 3D students based on their family member personalities, I can explore the same idea as a drawing project with my 2D class like the samples below.
If your day is split in such a way that you can do two very different things within the same day, that's great. Right now I teach sculpture my first two periods of the day, and then a prep period right after. So I can make the switch from clay to drawing for the rest of the day more easily. I just know though that not all schools "think" about their art teachers when scheduling.
4 keys to differentiation:
Once you have decided on the "essential bit" to be learned, you can vary the media, depth, complexity, and theme to meet each level's needs and abilities.
Media is easy: It's more about safety and your mess tolerance.
For a safety example in sculpture, where kinders might rip or use precut paper, elementary students will use scissors, and your upper grades might be allowed to use exacto blades or even power tools. Another media example would be crayons, markers, ink and brushes, and the use of dip pens. If I handed my high school kids crayons, they'd think I was punishing them, and I would certainly never give a kinder class dip pens and India ink.
As for depth, when I do an illustration that includes steps or panels. (Like a poem, joke, or story) I would do just 4 steps for the younger students, 6-9 for the middle years, and 9 for the high school adding a compositional component to the work. (I showed this above.)
If the topic was perspective or space, elementary age students could begin to learn about horizons, and making things larger or smaller to create the illusion of depth. They may even be able to do some rudimentary perspective by 4th grade, but one point perspective should be held for the middle school years, and multiple point perspective for the high school students.
In complexity, I think about what will challenge but not frustrate each grade level. Lowenfeld's levels of development can be helpful.
It might be fun to have your kinder-kids do perspective, and if you take it step by step, they will follow your directions and make something that looks like they may understand it. But the fact remains, most, if not all, will not. They can emulate some tricks, copy some formula, but they will not understand in any meaningful way. It's a waste of your time and there's. Their brains are simply not ready to process that information. There may be a rare savant that can, but it's not true for the population. The same is true having older students do work that is really meant for lower elementary. They may have fun, fingerpainting, but they will be learning very little because they have not been pushed.
As for interest, what grabs their attention? What holds their interest? Would you explore horror themes with kinder students allowing illustrations of Pennywise the clown from the movie It? Of course not. Learning what interests each grade level allows you to create lessons that will hold their interest. You might even want to speak to other teachers of that grade to see what they are exploring with their students. If the 4th grade does a unit on Egyptian history, it would certainly be in your own best interest to explore something related to that in your class.
For one thing you don't have to re-teach the content, they come to you with a base of knowledge, and now they can apply it to an art exploration which will be all the richer with the additional information.
Lower grades could explore making their name in hieroglyphics. Middle schoolers could make their own death masks, high school students could make a canoptic jars to house their entrails with a figure head they feel expresses their inner spirit animal.
Below are more art experiences by my students, grouped horizontally, with the elementary version on the left, middle school in the middle, and high school on the right. Nearly any project can be simplified for lower grade levels (Or for special needs students), and made more challenging for older students, when you root out the target of what you wish to teach.