2. My name is Francesco and I am a teacher of
Mathematics and Physics at the Scientific
High School "Giuseppe Battaglini" in Taranto
TARANTO
ITALYLogo «G. Battaglini»
3. The Scientific High School is a
school in which the sciences have
considerable importance
4. The disciplines I teach are the
subject of the second written test in
the final exams of the final year
5. Normally Mathematics and Physics
are not loved very much by Italian
students and by Italian people in
general
Vade
Retro
6. but many objects of every day life (hairdryer,
smartphones, televisions, etc.) without
science and mathematics, that is the basis of
all sciences, would not exist.
7. Today I'm going to show you a
typical simple physics lesson
that I teach in my school.
I tried to make it nice
(I HOPE!)
8. Let's start with a couple of questions
Someone will think
"Let's get off to a good start!!!"
9. Mirror, servant of my
cravings who is the most
beautiful in the realm?
Are the two images identically the same?
10.
11. Reflection is the phenomenon by
which a wave, which propagates
along the interface between
different means, changes direction
due to an impact with a reflective
material.
12. Examples of wave reflection
Light reflected from a mirror
A sound wave
reflected from a
mountain creating
the echo
13. The ray of incidence, the
perpendicular straight line to surface
at the point of incidence and the
reflected ray are coplanar
The first law of reflection says
14. Ƹ𝑖 Ƹ𝑟
Ƹ𝑖= Ƹ𝑟
The second law of reflection says
The angle of incidence ( Ƹ𝑖) is equal to
the angle of reflection ( Ƹ𝑟)
15. 𝜃
𝜃
90° − 𝜃 90° − 𝜃
The laws of reflection are also
used in the game of snooker
16.
17. In a mirror the images are formed
through the phenomenon of
reflection of the rays emitted by a
source on the mirror itself
18. A flat mirror creates a VIRTUAL image
because it is obtained by the apparent
intersection of light rays.
The object can be seen as if it were
placed behind the mirror.
The image is straight,
it has the
same symmetric size (lateral inversion)
at the right instead of the left
19. By placing a bright object in front of
a flat mirror and looking into the
mirror, the eye sees the image in a
position inside the mirror.
Light source
Mirror floor
20. The eye sees the image that is
obtained through the extensions of
the rays reflection.
For this reason, it is called Virtual
Light source
Mirror floor
Virtual image
21. How to draw with
ruler and compass
the image of a simple
object reflected in a
flat mirror
22. Step 1: Draw the perpendicular ray to
the mirror from the object head
23. The ray is reflected on itself ( Ƹ𝒊 = ො𝒓 = 𝟎°)
and, therefore,
I consider the extension within the mirror
24. Step 2: I conduct a second ray from the head of
the object and through the laws of reflection I
draw the extension of the reflected ray.
The two extensions meet at a point (P) that is
the head of the image
25. Step 3: I repeat the procedure (steps 1
and 2) for a point of the base
26. Step 4: Symmetrically I reproduce the
source in the virtual zone
(lateral inversion)
27. Let's go back to our evil queen
When you see it in the mirror ....
29. The evil queen sees her image that
is not real but virtual and
symmetrical (lateral inversion).
Maybe that's why Snow White is prettier?
I don't think so!
