Midterm Preparation

To prepare for the midterm on Tuesday, we went over the powerful ideas that we have developed about light and shadows. 1) A light source projects light in many directions. The evidence that the students have for this phenomena are the initial drawings they drew in the diagnostic questions, the observations they made when playing with an object in front of a light source (shadows were created), and also the simple fact that they can see everything around them. 2) Light travels in a straight line until it hits another object. The evidence that the students have for this phenomena is the ray diagrams they drew when explaining the pinhole cameras. If light had not traveled in straight lines, the image of the light bulb would not have appeared upside down. 3) If an object is non-reflective, light bounces off in many directions. If an object IS reflective, light bounces off at the same angle at which it hits the object (Angle of Incidence=Angle of reflection). The evidence we have for these powerful ideas come from the exploration with mirrors and non-reflective objects. This was also demonstrated when we quickly rolled a basketball and it hit the wall, and bounced back at the same angle in the opposite direction. This gave the students a visual image of the way light rays reflect off smooth objects. 4) To see something, a light ray must travel to the eye. The evidence for this powerful idea is that if we close our eyes, we cannot see anything. All of these powerful ideas are going to come in useful on the midterm. Also, pictures, diagrams, and explanations of the students' learning processes will be useful. I think that the students are glad Emily reviewed these powerful ideas and gave them a much more clear understanding of what she expects to see on the midterm.