## Ms. Emily: Signs of Life

On Friday the students were looking at 5 mystery objects and they had to determine whether or not they were living.  They were supposed to base their assumptions on the characteristics of life.  For some of the objects, the students had a hard time determining whether or not they were living.  One such object was a dehydrated polyacrylate bead, where they observed it changing in size (it absorbs water and is a hydrogel), and they assumed this meant the bead was growing and needed water and was therefore alive because growth and needing water are signs of life.  They had a hard time understanding the difference between growing (e.g. a seed sprouting or a baby growing into an adult) and changing in size.

The students also had to do a notebook check, where the students had to give themselves points on a sheet of paper for having certain assignments in their notebook.  Then of course, Ms. Scali and I came around and checked them.    Many of the kids did not have their points totaled when I came around.  Even though this isn’t a math course, I still thought it was a good idea to request them to total their points, and I noticed something really interesting with the way they totaled them.  A lot of the students only missed a point or two.  Rather than just subtracting the missed points from the total points listed, they added up all of the points, which leaves a rather large margin for error.  I had to ask several of them to check their total points because they were wrong.  I even mentioned to some of them the number of points they were missing and they would still just try adding up the total points.  Why are they so afraid to subtract?