Day 61: Onion Root Tip Lab


Science 9 – Today I thought I’d have the students try a microscope lab.  This is a pretty typical lab that is frequently done across all schools. Students are asked to examine a slide under a microscope and to see if they can recognize cells that are in the various stages of mitosis.  I think this lab would be extremely difficult with the above graphic to help.  At first, students will just see a few hundred cells that all look the same. It takes a reasonable amount of time before subtle differences are seen.  The above slide is more clear than what the students actually see because in order for the students to have this level of magnification the depth of field is much smaller.

One of the hardest things for the students to do is to actually get a slide in focus.  I had to spend a lot of time helping with this. My first suggestion was for them to initally focus on a piece of lettering that was on the prepared slide.  However, many students would only have their slide in partial focus. I found that very interesting – I don’t know why a person would stop focusing, or keep playing with the focus and see that the sample because sharper and sharper.

Day 47: KWL Chart on Reproduction


Science 9 – Today was one of those really productive and useful lessons, almost insidious in fact.  Instead of doing an individual KWL sheet, I put students into random groups and had them whiteboard their work. It was a significant improvement over any other KWL activity I have done.  Not only were students able to summarize a fair bit of detail of previous knowledge, the real winner was in the great questions they wondered about and asked about.

I started off this unit with one primary Essential Question: “Why are both meiosis and mitosis required?”  A more thorough inquiry is based on the idea of finding out what meiosis and mitosis are, and what roles organelles, DNA, genes and proteins play.  I’m don’t think I’ve been transparent enough with them about these underlying questions (and they don’t ask), but next day I’ll try to get them to tie these ideas together.

Some of the questions the KWL generated include:

  • What are all the organelles?
  • What do genes do?
  • Why am I different from my parents?

There were many others but I forgot to take pictures of the whiteboard!