Seeing Things
Image Location in Plane Mirrors
We see the object when looking directly at it
because rays of light go from it straight into our
eyes.
Experience has trained our Eye-Brain that things are
located in the direction the light comes from.
When we look in the mirror, we see an Image of the
object.
Experience has trained our Eye-Brain that things are
located in the direction the light comes from.
Rays of light must be coming straight from what we
see in the mirror (the image) into our eyes. That is
the way we see things.
The image appears to be behind the mirror, but the
light rays cannot come through the mirror. Mirrors
are opaque.
Two Questions
1) Where does the image appear to be located?
2) How can the light rays appear to go through
an opaque mirror?
Question 1)
Where does the image
appear to be located in a
plane mirror?
Image Location Lab
Image Location Lab
1) Place an object in front of the MIRA on a sheet of
scrap paper.
2) Notice that you can see a reflection of the object in
the MIRA. If you use an Object/Image Stick, you
even see the word Image in the reflection.
3) Place an Image locator (a second Object/Image Stick)
behind the MIRA.
4) You can see the Image locator through the MIRA. If
you use an Object/Image Stick, turn it around so that
you can see the word Image through the MIRA.
5) Move the Image locator until it appears to overlap the
image.
6) Trace the location of the object.
7) Trace the location of the mirror.
8) Trace the location of the image (Image locator).
9) Move the object twice (2X’s).
10) Trace all object and image locations.
11) Be careful to keep the MIRA in the same place.
12) You should have a piece of
paper that looks similar to this. O1
O2
I2
O3
13) Draw a line from the centre
of the object to the centre
of the image so that you
have a piece of paper that
looks similar to this.
O1
I3
O2
O3
14) What are two observations that can be used to
predict the position of the image in a mirror?
15) Try the Bull’s Eye activity.
I1
I2
I1
I3
Your Turn
Do the Image Location Lab
Image Location Lab
Answers Follow
1) What are two observations that can be used to predict the
position of the image in a mirror?
a) The distance from the object to the mirror (dO).
is the same as the distance from the image to the
mirror (dI). Or dO=dI.
b) The line connecting the object and image
intersects the mirror at 90 °.
2) Use your observations to show where, and then describe how,
you would place a MIRA or Reflect-View so that the tip of the
arrow always appears to hit the Bull’s Eye.
a) Draw a line connecting the Arrow Tip and the
Bull’s Eye (object & image).
2) Use your observations to show where, and then describe how,
you would place a MIRA or Reflect-View so that the tip of the
arrow always appears to hit the Bull’s Eye.
b) Place the mirror in the middle of the line
dO=dI.
2) Use your observations to show where, and then describe how,
you would place a MIRA or Reflect-View so that the tip of the
arrow always appears to hit the Bull’s Eye.
b) Place the mirror in the middle of the line
and rotate it 90° to the line.
2) Use your observations to show where, and then describe how,
you would place a MIRA or Reflect-View so that the tip of the
arrow always appears to hit the Bull’s Eye.