It is easy to have pictures that you can not identify without some means of careful labelling. You will probably not want to make movies from the stills with sound as some of the advertising suggests, but labelling is an important option for teachers. The electronic viewfinders are also and important feature. For many science shots you will want to do some real closeups. If you need this option, be sure to check the focus by trying a picture at the desired distance.
Storage can be expensive.
Check out the cost of storing pictures on the camera you are considering. The information below is specific to the use of the Kodak DC50 which we purchased 2.5 years ago. I would not make the same choice today, but it is the one I am familiar with. The digital camera provides several major advantages for teachers preparing material for instruction. No extra boards are required for digitizing.