SUBJECT
GRADE
LEARNING UNIT
NATURAL SCIENCES
9th
HOW DO THE WORLD'S
COMPONENTS CHANGE?
TITLE OF LEARNING
OBJECT
What differences exist between a collision generated wave in
water and a wave generated on a string?
CURRICULAR AXIS
STANDARD
COMPETENCIES
Physical environment
Explain conditions of change and conservation in various systems,
taking into account energy's transfer and transport and its interaction
with matter.
-To verify reflection, refraction and diffraction phenomena of
mechanical and electromagnetic waves, in order to then differentiate
between them.
- To describe the operation of a ship's radar.
- To respect the opinions of peers regarding the concept of waves
LEARNING OBJECTIVES
SKILLS/ KNOWLEDGE
Skill 1. Infers that a graphic representation can be used to describe
multiple periodic phenomena that occur in nature.
Skill 2. Classifies waves according to their dimension, direction and
medium propagation.
Skill 3. Establishes the relationship between the duration and
frequency of a wave.
Skill 4. Tests reflection, refraction and diffraction phenomena with
mechanical and electromagnetic waves that produced the concept of
environmental economics.
LEARNING FLOW
ASSESSMENT
GUIDELINE
1. Introduction
2. Objectives. The teacher presents the objectives and can
establish other similar ones if he or she so desires.
3. Main. Activities
4. Activity 1. Periodic phenomena in nature.
5. Activity 2. Duration and frequency.
6. Activity 3. Reflection, refraction and diffraction.
7. Abstract
8. Homework
9. Evaluation
10. Glossary
11. Vocabulary Box
To be able to answer the question one should have basic knowledge
of the concept of a wave, its parts and types.
Stage
Learning flow
Introduction
The
student
observes the
platform, and
the
teacher
tackles
any
doubts.
Activity 1
Teaching/Learning Activities
Recommended
Resources
The teacher will contextualize using the Multimedia
following text.
support
and
platform
In the universe there are several types of waves. recources
Some travel long distances; others for very short
distances, but all of them can have variables in
their movement, direction, intensity, etc.
Skill 1. Infers that a graphic representation can be
used to describe multiple periodic phenomena that
occur in nature.
The teacher shows a graph to the student and
talks about the exercise contained in the virtual
resource.
Development
Observe the following graphs and determine if
they can describe different periodic phenomena
that occur in nature. Give examples of some of
them with their respective graphs.
Seismographs for the 1985 earthquake. Graph
1. Records observed during the 1985 earthquake
in
Mexico.
Taken
from
https://cuicatlali.wordpress.com/page/2/
Graph
2.
Taken
from
https://miguelmorateorganologia.wordpress.com/n
ociones-basicas-de-acustica-musical/
The parts of the image above are described as
follows:
Magnitudes of time:
- Duration (T) is the time between two consecutive
steps of a periodic motion at the same point going
in the same direction. It is a cycle's length of time.
It is measured in seconds.
- Frequency (f): the number of times that a body
which performs a periodic movement passes
through the same position in the same direction (in
a unit of time). Cycles per second (hertz, Hz).
- Phase difference: the time that goes by from
the moment that their elongations reach zero,
until the moment in which the other reach the
same value in the same direction.
- Wavelength: the distance that a wave travels
over a period of time. It can vary greatly: a
sound at 16 Hz has a wavelength of 21.25 m
and one of 20,000 Hz, 1.70 cm.
Magnitudes of space:
- Cycle (c): a route taken by a body from any
position of its trajectory until it returns to its same
direction.
- Elongation (x): distance at a given moment
between a body and its position at rest
- Amplitude (A): distance between the point of
equilibrium and each of the endpoints. This is
the maximum elongation.
Seasons of the year:
The Analemma is a closed curve that plots the
position of the sun in the sky by recording its
position every day of the year, at the same time
and from the same place of observation.
Declination of the Sun. Summer solstice, autumn
equinox, spring equinox, 21st of December (winter
solstice).
Graph
3.
Taken
from
https://virgiliotovar.files.wordpress.com/2013/06/f7
bee-analema2bcompleta2b2.jpg?w=724&h=490
Remember that...
Activity 2
Natural phenomena generate waves, whether
mechanical or electromagnetic, and these can be
represented graphically, as they have frequency
and duration.
Classify the waves according to their
dimension, direction and their medium of
propagation.
In the nature, there are different types of waves:
mechanical,
electromagnetic,
longitudinal,
transverse, unidimensional and two-dimensional.
After observing the following video, indicate how
each wave is classified.
https://www.youtube.com/watch?v=jzQSJsjtrAk
Activity 3
Establish the relationship that exists between a
wave's duration and frequency.
Work on the following exercise in pairs:
1- Take a rope and make it move for a certain
amount of time with short, rapid movements.
Then, repeat the exercise but with wider and
slower movements.
2- Observe the quantity of waves that are created
in each of these cases and give their frequency
and duration.
Remember that...
Frequency is =
𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠
𝑡𝑖𝑚𝑒
𝑡𝑖𝑚𝑒
and duration is =𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑜𝑠𝑐𝑖𝑙𝑙𝑎𝑡𝑖𝑜𝑛𝑠 .
Activity 4
Skill 4.
Test reflection, refraction and
diffraction phenomena with mechanical and
electromagnetic waves.
The teacher proposes the exercises in the
following box, in order for students to test the
phenomena of reflection, refraction and
diffraction in each experiment.
Mechanical
1Place
water in a
bowl
and
drop a small
object in it.
Notice how
the
waves
are reflected
on the walls
of
the
container.
2- Place a
glass plate or
other object
that
is
covered by
water in a
bowl,
tap
water
from
the opposite
side of the
object
and
observe how
the
waves
change
or
twist.
3- In a bowl
with water,
place a strip
of
wood
with a hole
in it, dividing
this
container in
two, tap the
water at one
end
and
watch
the
waves
propagate
after
the
medium's
disturbance.
Electromagnetic
- Point a laser at a glass of
water, which should have a little
salt or milk in it in order to
better observe the process.
-Put a pencil in a glass of water
and notice how it looks like it
has doubled. This is due to the
change in the medium of
propagation of light, which hits
the pencil making it look
different.
4- Using a scalpel, make a line
on a CD and, using tape,
remove the recordable part.
Point a laser at it and observe
closely how the light is
diffracted.
Did you know that...
The visible spectrum of the human eye has a
longitude of 400 to 750 nanometres.
Abstract
Homework
The
teacher According to the information above, it can be said Look
presents
the that a wave is a disturbance that propagates from bibliography
topic
its point of occurrence to the environment
surrounding that point. Waves can be classified
according to their means of propagation in
mechanical and electromagnetic waves; according
to their direction, in longitudinal as well as
transversal waves; and according to their size, in
one-dimensional and two-dimensional waves.
Similarly, this disturbance has a frequency and a
duration
which
may experience
different
phenomena such as reflection, refraction and
diffraction.
The
teacher The teacher proposes the following questions
presents
the and exercises, which he or she will later solve.
topic
1. Take a bowl and fill it with water. When the
water is completely still, lightly touch the centre of
the surface once. Describe your observations.
2. Comment on cases in nature where reflection,
refraction and diffraction occur.
3.
What wave property is radar based on?
Explain its function.
4.
In some cases we talk about flat waves,
circular waves, spherical waves, wave rays, etc.
Cite examples of such cases.
Evaluation
5. In groups of three, work on a presentation
describing the concept of a wave. Have a graphic
representation with some its types and where they
occur.
1. Multiple choice questions with multiple possible
answers.
Mark with an X the letters that correspond to the
correct answers:
I. In a mechanical wave:
a. molecules transfer energy to each other.
b. molecules do not transfer energy to each
other.
c. the bodies' mass travels through matter
without any of the energy traveling.
d. energy travels through matter without the
bodies' mass traveling.
II. Waves can be classified according to their ___
propagation.
a. longitudinal
b. mechanical
c. transversal
d. electromagnetic
III. The parts of a wave are:
a. crest
b. trough.
c. hill.
d. plain.
2. Multiple choice question with only one answer.
What phenomenon occurs when shaking a
rope at one end without letting go of it?
a) Natural.
c) Logarithmic.
b) El Niño
phenomenon.
d) Ondulatory
phenomenon.
3. Match the concepts in column A to the
definitions in column B by placing the letters in
front of the corresponding numbers.
Column A
Column B
1. b Refraction
a)
Distance that
2. e
Mechanical a wave moves
3.
4.
5.
6.
wave
f
Longitudinal
waves
d Reflection
c
Transverse
waves
a
Wavelength
b)
Distortion
c)
Perpendicular
d)
Change
in
direction
e)
Medium
for
propagation
f)
Parallel
4. Complete the following text by using the words
in the box.
Light
Mechanical
Medium
Electromagnetic
Sound
Vacuum
There are different types of waves. Their principal
characteristics allow us to classify them in
mechanical and electromagnetic. Mechanical
waves, like sound and ripples on the surface of
water, need a medium through which they
propagate; the others don't need a medium and
can travel through vacuum.
Radio waves,
television waves and light waves are in this last
category.
Glossary
 Mechanical waves: waves that need a medium Printable
resources.
in order to propagate.

Electromagnetic waves: carriers of energy
emitted by vibrations (often from electrons),
formed by oscillating magnetic and electrical
fields which regenerate each other.
Vocabulary
Box

Longitudinal waves: waves in which the
individual particles of a medium vibrate forward
and backward, in the direction in which the
wave travels.

Transversal waves: waves where the vibration
is at a right angle to the direction of wave
propagation.

Unidimensional waves: waves that move in
only one direction.

Two-dimensional waves: these waves move
in two directions.

Reflection: when the rebound of a particle or
wave strikes the boundary between two media.

Refraction: the change in direction of a wave
when it crosses the boundary between two
media, at which point the wave travels at
different speeds.

Diffraction: the bending of light passing around
an obstacle or through a narrow slit, causing
light to scatter and the production of dark and
light stripes.

Wavelength: the distance between two equal
successive parts of a wave (successive crests
and troughs).

Nanometre: a metric unit of longitude with an
equivalent of 10-9m (one billionth of a metre).
 Movement: motion, or the act of moving.
 Plot:
to mark a route or position on a
trajectory, graph or chart.
 Earthquake:
the ground.
 Phenomenon:
"phenomena."
a sudden violent movement of
the
singular
form
of
 Spectrum: a band of colours produced by a
separation of the components of light (as seen
in a rainbow).
 Undulatory: having the form or appearance of
waves.
Bibliography





www.slideshare.com. Retrieved from
www.slideshare.com: http://es.slidesh
are.net/jolumango/ondas-14430970
Hewit, P. G. (2004). Física conceptual
novena ediciión. Atlacomulco: Pearson
Educación de México.
Merryxstopy. (March 10, 2016).
www.youtube.com. Retrieved from
www.youtube.com: https://www.yout
ube.com/watch?v=jzQSJsjtrAk
www.mailxmail.com. (March 10,
2016). www.mailxmail.com. Retrieved
from
www.mailxmail.com: http://www.ma
ilxmail.com/curso-fisica-imagenesondas-senales/tipos-ondas
1985, S. d. (March 11,
2016). Develando las geociencias.
Retrieved from Develando las
geociencias: https://cuicatlali.wordpre
ss.com/page/2/