Cells

This is how a 12 year old boy makes a model of an animal cell:
With Castles.
Of course.

The animal cell: Little Brother explains that a cell is a system just like a medieval castle.

Each organelle in the cell has a role...

The castle wall is the membrane of the cell

The king is the nucleus. He has the lineage or DNA and he is the command center of the cell

The hunter, or mitochondria, utilizes food for the cell/community.

Centrioles have double heads ( in this case triple) as paired structures, and assist the nucleus in mitosis 

Organelles (all the parts) act like knights to perform functions for the cell

Lysosomes break down food into smaller parts. This soldier is strong. SMASHes food into smaller parts!

Microvilli... I think he meant porous cell membrane, allows material in and out of the cell wall. This is the castle gate. 

Cytoplasm, or just the innards of the castle, creates a fluid support structure for the cell

His understanding of the cell parts is not perfect, but close enough for now. What I really appreciate here is that Little Brother read material about cells and UNDERSTOOD that a cell is a system within a system. I asked him if he wanted to make a cell model, thinking he would enjoy making a cookie with funky cell decorations on top. But he had his own idea, ran to the play room, and created this castle concept. Little Brother OWNS his experience and his learning. This speaks to him and his understanding of cells will be deeper because of HIS experience, and not because someone imposed a specific model on him.
This is what I love about unschooling. He has time, space, and permission to allow his understanding to unfold in his own passion and way.