Photosynthesis
This program (developed in Visual Basic) is in two sections, the first, useful for younger students, shows a animated plant, the second section shows a cross-section through a leaf and asks a student (volunteer?) to correctly arrange the labels.
An animated picture of a plant, it has cartoon, anthropomorphised versions of water, glucose, sunlight oxygen and carbon-dioxide that can individually be shown/hidden to make the picture simpler. There are also a few details about each "cast member".
I think it makes a nice background to start an explanation from and could be used with the worksheets at the bottom of this page.
It has not yet been finished as it was originally envisioned - the "Make it Night" button that would show respiration is not yet written..hopefully there is an enterprising teacher out there somewhere?
Shows a cross-section through a leaf. Initially the parts of the leaf are labelled incorrectly. A student volunteer can then use the drop down boxes to move the labels to the correct places.
The software can be asked to mark the current attempt or show the correct answers.
From here you can download (right-click and choose "Save Target as"):