1. Optics - Parallax Explain what parallax is
Give an example how parallax occurs
Locate an image in a plane mirror

2. Optics - Parallax
Parallax is a difference in the apparent position of an object due to the motion of an observer.
Draw a mark on a nearby wall.
Place a metre stick upright on your table.
Close one eye, and move the metre stick and your head until the metre stick blocks the mark.
Keeping the metre stick in place, move your head until the mark appears again.
This is parallax – moving your head appears to move the metre stick from in front of the mark.

3. Optics - Parallax
To Locate an image in a Plane Mirror by the Method of No Parallax
Stand a plane mirror upright on a sheet of paper on a flat surface.
Stand an “object” pencil upright near the mirror, keeping it in place with blu-tack.
Looking into the mirror, move a second “search” pencil behind the mirror and align it with the image of the first pencil.
By moving your head and the search pencil, find where there is no parallax between the image and the search pencil.
Mark the position of the object and search pencils, and the plane mirror on the paper.
Measure and compare the distances from the plane mirror to the object pencil and the image.