Sequence 2: earthquakes

The following translation is graciously provided by ISTIC.

This sequence starts with a documentary study which makes it possible to define an earthquake. Starting from the damage observed a scale is introduced (MSK scale, which measures the intensity, i.e. local impact of the damage) then the propagation in concentric circles of the seismic waves is studied (with documents and experiments). The study of the location of earthquakes makes it possible to highlight the tectonic plates and, from there, to get to the cause of the phenomenon. Experimental activities facilitate the study of how the earthquake is created, and how it can be detected. The Richter scale is introduced, in order to measure the energy released by the earthquake (magnitude). Finally, after having referred to the required behaviors in the event of an earthquake, the class finishes this sequence by testing various aspects of earthquake-resistant buildings.

Detailed summary:

 


Session 2-1: What is an earthquake?

duration

1 hour

material

For each pair:
- choice of: a photocopy of sheet 17 or sheet 18

objectives

- A seism is an earthquake: it manifests itself by tremors which can cause collapses and landslides
- The duration of a seism varies from a few seconds to a few minutes
- A seism can cause a lot of damage and cause many casualties
- A seism can sometimes cause tsunamis

skills

- Locate explicit information in a text
- Infer new information (implicit)
- Practice an investigative approach: know how to observe, question

main Subject

Sciences

vocabulary

Seism, earthquake, tsunami

Initial question

The teacher asks the pupils what they know in connection with seism (while starting to use the vocabulary: seism, earthquake…).
At this stage, it is not sought to define these terms precisely, but only to identify what the pupils know.

Pedagogical note
- Very often, the pupils use a very precise vocabulary (seism, magnitude, core, plates, tsunami…), which they know because of the strong media coverage of certain events (the earthquake which occurred in Japan in March 2011, for example), but without necessarily mastering the associated concepts. For some, a seism is a quake of the entire Earth, for others, it is a local phenomenon even more rarely associated weather phenomena (“there are waves that can cause hurricanes”).
- Generally, the word “plate” used by the pupils indicates in fact a continent.
- For the majority of pupils, an earthquake is a very violent phenomenon, during which the ground opens literally into two (the risk for the population is they fall into the cracks).These erroneous representations will progressively be corrected as this session progresses.

Research (documentary study)

The pupils are divided into pairs, half of them receive a photocopy of sheet 17, and the other half a photocopy of sheet 18. These two sheets include press articles relating to earthquakes which occurred recently, in France or abroad, mild or dramatic depending on their magnitude and the degree of preparation of the populations.

Pedagogical note:
The teacher can provide other documents to support this session (in particular if the class is in a seismic area, local references would be desirable). For instance, the following website offers press reviews about earthquakes throughout France: http://sismalp.obs.ujf-grenoble.fr/coupures/coupures.html

Pooling

After reading these texts, the teacher hosts a collective discussion to achieve an operational definition of a seism: it is an earthquake which appears as tremors that can cause collapses and landslides. A seism is a very short phenomenon (a few seconds to a few minutes), but which can be very violent.
A seism can also create a tsunami: a set of high waves which can cause extensive damage.
The documents show that France (including mainland) is subjected to seismic risk. The pooling also allows to pupils realize that the main risk related to a seism (except a tsunami) is the collapse of buildings (and not the ground opening into two as many children think). It can be noted that there some countries are better prepared than others, with appropriate structures.

Scientific note:
The seism which occurred in March 2011 in Japan illustrates this aspect well: the seism itself caused very little damage (it was the tsunami which had catastrophic consequences). The majority of the buildings resisted the tremors well, as shown in this very spectacular video where buildings can be seen swaying… but not collapsing. Viewing this video can be a good continuation of this session.

Conclusion – written records

The class works out a collective conclusion which is noted in the scientific notebooks. Here is an example of conclusion:
At the time of a seism (or earthquake), tremors, very short but which can be very violent, can cause the collapse of buildings. A seism can also cause a tsunami.
The teacher asks the pupils to clarify questions that they have about seism, and collects them on a poster (they will be answered progressively during the sequences that follow).

Grade 3/4 of Francis Bachelet and Corinne Dauchart (Rosheim)

Multimedia extension

The first multimedia animation created for this project is entitled “Living with risk”. It is a cartoon telling the history of past natural disasters, and the means by which man protected themselves from them.

 

Extension
In addition to the extension mentioned in the previous scientific note (to view a video showing the buildings swaying), this session can be supplemented by exploring the myths and legends surrounding earthquakes: a dragon in China, a catfish in Japan, a tortoise for American Indians…

 


Session 2-2: How to measure the intensity of an earthquake?

duration

1 h 15 min

material

For each group:
- a photocopy of sheets 19 to 22

For the class (optional):
- video projector or 1 overhead projector to project sheet 22

objectives

- A seism spreads in a concentric way
- The place where it can be most strongly felt is called “epicentre”
- The further away from the epicentre, the lesser the damage
- The damage caused by a seism is measured on the MSK scale. We talk about intensity
- The intensity of a seism varies from I (unperceivable seism) to XII (catastrophic damages)

skills

- Infer new information (implicit)
- Know the principal physical geographical characteristics, locate them on maps of different scales

main Subject

Sciences

vocabulary

MSK Scale, intensity, epicentre, concentric

Initial question

The teacher asks some pupils to point out the various effects which can be felt during an earthquake (reminder of the previous session).

Research (documentary study)

The pupils are divided into small groups and receive a photocopy of sheet 19, which describes the damage caused (corresponding to the 12 degrees of the MSK scale), this damage being placed at random. Work consists in placing these effects in the order from the least to the most serious (by cutting out and sticking the items onto sheet 20).

See below, the list, in order, as well as the corresponding MSK intensity:

Intensity MSK

Damage

I

Residents do not feel anything, the seism is only detected by the more sensitive instruments.

II

Only some people who feel weak vibrations wake up.

III

The glasses and dishes tinkle, the chandeliers swing.

IV

All the people who are awake strongly feel the tremors.

V

All the people who were asleep awake, objects fall.

VI

Heavy pieces of furniture move. Many people are afraid. Tiles fall from the roofs.

VII

Some cracks appear in the buildings.

VIII

The buildings suffer extensive damage, chimneys fall.

IX

The most fragile constructions, in particular the houses, collapse. Underground pipes are broken. Roads suffer extensive damage.

X

Bridges and dams collapse. Railway rails are twisted.

XI

General panic. All the buildings, even the most solid, are destroyed.

XII

Cities are razed and landscapes are modified (cracks in the ground, rivers displaced…).

Pooling

The class shares various proposals, and reach a consensus. The teacher specifies that this description of the corresponding damage, is a simplified version of an international scale (known as MSK, for “Medvedev, Sponheuer and Karnik”, the three people who defined it).

Scientific notes
- In spite of the work completed in the previous sessions, many pupils persist in believing that, at the time of a seism, the ground opens up in two (cracks…). It is seen here that this is true only for exceptionally intense seism (XII on the MSK scale).
- Do not to confuse this relative scale (which measures the damage in a specific place) with the Richter scale, which measures the "absolute" force of the seism. The first is about intensity, the second, about magnitude. The Richter scale will be studied during session 2-7. So as not to confuse these two scales, the intensity (MSK) is noted in Roman numerals.
- Another scale similar to the MSK scale, but older, also exists: the Mercalli scale. In addition, this MSK scale was recently updated and clarified. The new version is called EMS98 (European macroseismic scale). This is not so well known among the public, so we prefer to use the original version here.

Research (documentary study)

The teacher then explains that the class will now use this scale to see how the same earthquake is felt in different places.
The pupils, divided into small groups, receive a photocopy of sheet 21 and sheet 22. The first document provides, for the same earthquake, various testimonies of residents of various cities, while the second presents these cities on a chart. The earthquake being studied is the one which occurred near Laffrey (Isère) on 11th January 1999.
As a first step, the pupils must determine the intensity of the seism in the different cities (relate the observed damage to the intensity on the MSK scale), then connect the cities in which this seism had the same intensity (plot the isoseismal curves, which will form circles).

Pooling

The rapporteurs of the various groups observe that these isoseismal curves (observed damage) are approximately circular. The teacher asks the pupils what this teaches them about the spread of the earthquake.

Scientific note
In reality, the spread is not perfectly concentric because of the nature of the terrain (more or less movable ground, relief) will locally reinforce or reduce the effects of the earthquake. The circles are therefore distorted. This subtlety seems however unnecessarily complex at primary school: we make it “as if” a seism is spread in a perfectly circular way.

The question then is to find the place where the earthquake was most intense, and to name this place. It is located at the center of the circles. It can be named “center”. The teacher explains that actually, it is called the epicentre.
The term “epicentre” is provisionally defined in the following way: it is the place where the earthquake can be most strongly felt (if there is somebody to feel it!). This definition will be modified later (Session 2-5), when the focus will have been defined.
A comparison can be made with what is observed when a stone is thrown into a pond: the waves form concentric circles and are less high as one moves away from the center.
Here is an outline of these data (the star represents the epicentre of the seism), as well as the corresponding intensities.
It can be very useful, for this pooling, to project sheet 22 onto the board in order to enable one or more pupils to draw the various circles and place the epicentre.

Pedagogical note: use of the interactive digital Whiteboard
Such a session can easily lend itself to the use of the interactive digital whiteboard (IDW), including at pooling time: the map is displayed on the board, a pupil places the values of the intensities and another draws circles. In particular at the moment of the pooling: the chart is posted on the IDW, a pupil comes to place the values of the intensities and another to trace the circles. The IDW is also used to find the epicentre.

Conclusion

The class works out a conclusion in the form of a summary, for example:
A seism spreads in a concentric way. The place where it can be the most strongly felt is called “epicentre”. The intensity of a seism can vary from I with XII: this intensity measures the extent of the damage.
This conclusion is noted in the scientific notebooks.

Variant

The teacher who wishes to devote more time to the production of writing will be able to adapt this session in the following way (allow 2 hours):
1. Ask the pupils to imagine a scale of perception of the earthquake (in 4 or 5 degrees) and to write the corresponding texts. Example: the earthquake is unperceivable/tremors are felt, but there is no damage, etc.
2. Read sheet 21 and refine as the above definitions needed, and characterize, on this personal scale, the severity of the seism in various places.
3. Make a documentary study, then introduce the MSK scale.

Extensions
In visual arts, the MSK scale can be illustrated: feeling of the residents, damage observed, changes to the landscapes…

 


Session 2-3: How does a tremor spread?

duration

1 hour

material

For each group:
- coloured pasta (or other small objects, light, of similar size and weight, but of different colors)
- a mallet
- an A3 sheet

For the class (optional):
- a digital camcorder

objectives

- A seism spreads in a concentric way
- The further away from the epicentre, the lesser the damage

skills

- Handle and experiment, formulate a hypothesis and test it, debate
- Express the results of a measurement or research using scientific vocabulary verbally and in writing

main Subject

Sciences

Initial question

LThe class reviews what was seen during the previous session, namely: the vibrations of a seism are spread in concentric circles, and their intensity decreases as one moves away from the center. The teacher asks the pupils to imagine an experiment allowing them to verify this.
Some pupils can propose, for example, throwing an object into the water and to observe the shape of the waves (concentric circles). This experiment can be carried out collectively, but the teacher must ensure that the pupils understand that this is an analogy. He encourages them to carry out an experiment which brings into play vibrations comparable in nature as that of an earthquake. “It would be necessary to vibrate something solid.”
Rather easily, the pupils then propose to use their table, and to lay the objects in a circle (“We move the table, which makes the objects fall, we look on which circle the objects fall the most easily.”) The question of the shock is discussed: is it necessary to strike the table over or under, or to knock two tables together? The last proposal (knock two tables together) can easily be discarded, because we would not have, in this case, a localised epicentre. To be more realistic (a seism comes from the below), it is then decided create a shock under the table, in the middle.

Pedagogical note
- If the tables are equipped with boxes below, it is necessary to hit between the box and the table (with the mallet)… or, in the worst case, from the top of the table.
- The mallet blow must be given as precisely as possible in the middle of the circles.
- This experiment can be introduced differently, by showing the pupils the material available, and asking them how to use it to answer the question asked.
- Tip: to colour pasta, just dip them a few seconds in the food dye and quickly dry them in the oven so that they do not soften.

Research (experimentation)

The pupils are divided into groups and carry out their experiment.
For example, they place coloured reference marks (colored pasta, pieces of sugar, dominos…) on the concentric circles (a different color for each circle) plotted on an A3 sheet placed on a table. By giving a blow under the table using a mallet (in the center of the circles, which represents the epicentre), a vibration is created which will be spread in the table. Coloured reference marks are moved (or turned over if they are dominos), and their movement is in all directions: in the plane of the sheet but also vertically. The more one moves away from the point of impact, the less the coloured reference marks moved.


Grade 3/4 of Sylvie Vernet (Lyon)

Pedagogical note
- If you have a digital camcorder, you can film the experiment in such a way as to show the vertical displacement of the elements. A video of this manipulation is available here.
- If you hit too hard, all the pasta is ejected and nothing can be seen any more. To properly quantify the effort, it is preferable to use a mallet.


Grade 4 of Stéphanie Barbosa (Verniolle)

Pooling and conclusion

This experiment shows that a tremor is spread in concentric circles. The more one moves away from the epicentre, the more the vibrations decrease, and the lesser the damage.
This result is noted in the scientific books as a conclusion.
This activity makes it possible to introduce a new question: in reality, what produces the tremor (what plays the part of the mallet blow)?

 


Session 2-4: Where are earthquakes located?

duration

1 hour

material

Choice:
- computers connected to Internet (1 computer per pair)
- or, for the class: a computer + a video projector
- or, if there is no computer equipment, for each pair, a photocopy of sheets 7, 8 and 23, as well as a world map

objectives

- The Earth's crust consists of plates moving against each other
- The majority of the seism can be found at the borders of these plates

skills

- Know the main physical geographical characteristics, locate them on maps of different scales
- Read and use maps
- Read a digital document

main Subject

Sciences

Preliminary pedagogical notes
- This sequence is based on a multimedia animation, produced by La main à la pâte and Universcience.
- This session is very similar to session 1-8 about the location of volcanoes. It can be carried out independently (one pair per screen), or collectively, using a video projector
 * If the pupils are in front of the screen, they will need strong coaching (if not, they “play” with multimedia, without being really attentive, and without learning anything).
 * If the sequence is carried out collectively, it is advisable to facilitate it properly, to stop often and ask the pupils to anticipate (“in your opinion, what will occur if… ») so that they are not passive.
- An alternative is also proposed (in the form of a documentary study) in the case where the use of multimedia is not possible. The two alternatives are not exclusive.

Initial question

The previous sequence has enabled questioning the origin of a seism: what creates the tremor? The pupils reflect individually and note their hypotheses in their scientific notebooks.

Pedagogical note
The pupils of the primary school in general do not have a precise idea of the cause of an earthquake. They link the origin to a volcanic or weather cause (for example, heat causes cracks in the ground), or to a human origin (wars/bombs…).

In the likely case where the pupils do not establish a link between the origin of earthquakes and the movements of the tectonic plates, the teacher guides them with another question: do earthquakes take place in particular places?
He then introduces the multimedia animation which will be used to answer this question, as would be done for a documentary research.

Research (multimedia animation)

The pupils are divided into small groups, ideally in pairs, each group having a computer at their disposal, with the animation uploaded onto the screen.
The interactive animation is composed of several elements which make it possible to visualize:
- the inner layers of the Earth;
- tectonic plates (particularly, their displacement since Pangea can be followed);
- location of seisms on Earth, which can be compared with the layout of the plates;
- the location of volcanoes (this part can be skipped, because it was already addressed at the time of session 1).


Animation « Planet Earth »

Pooling

After using the animation, the pupils share what they have learned:
- TThe earth's crust consists of plates which move against one another (the teacher ensures, if needed using a world map, that the pupils properly understand the difference between plates and continents).
- The majority of the seism can be found at the borders of these plates.

Scientific note
In fact, earthquakes are not exactly on the borders of the plates, but in a widened band (going up to a thousand km) around these borders. At primary school, this nuance does not seem important to us.

Conclusion

The class can (temporarily) conclude that there is perhaps a link between the movements of the plates and the origin of the tremors. The following session will make it possible to, experimentally, check, if this proposal is relevant.

Variant

If this multimedia animation cannot be used in class due to lack of equipment, a similar session can be conducted by using maps (sheet 7, sheet 8, sheet 23), as well as a world map. The study of sheet 23 shows that earthquakes are not distributed everywhere: the majority of the major earthquakes are localized on “lines”. While looking at the significance of these lines, the 2nd map is introduced (sheet 7, and it can be noted that these lines correspond to the edges between the tectonic plates.
The pupils are then asked to trace the outlines of South America on a world map, then to place this copy on a world map while trying to join South America to Africa. The pupils notice that the two continents “fit into” each other, they then formulate hypothesis to account for this. A possible explanation is that these plates moved and that at some point in time, the two continents were only one. The same work can be done with Arabia and Africa to get to an identical report and hypothesis.

The teacher then introduces sheet 8, which explains continental drift, and proposes the pupils put the various stages since the Pangea in order. For convenience, one can start by coloring the continents (in order to better follow them).
The answer key is given below (quaternary = today):

The session ends in a collective discussion during which the teacher explains the link between the movements of the plates and the seismic activity.

 


Session 2-5: What is the origin of the shock?

duration

1 hour

material

For each group:
- 2 wooden rafters on which a hook is fixed
- sandpaper, rubber bands
- iron rods, cubes to be piled up or a small container filled with water…
- velcro or double-sided sticky tape

objectives

- An earthquake is created by a break or a violent movement of the rock
- The place where this break or this displacement occurs is called the focus
- The focus of a seism can be more or less deep (10 to 700 km)
- The epicentre is located on the surface vertically above the focus

skills

- Handle and experiment, formulate a hypothesis and test it, debate
- Express the results of a measurement or research using scientific vocabulary verbally and in writing

main Subject

Sciences

vocabulary

Focus

Initial question

The preceding session made it possible to identify a possible cause: movements of the plates against each other.
The teacher asks the pupils if this movement is uninterrupted or is in jolts . He then encourages them to imagine an experiment that would allow them to confirm their hypothesis or not. In the event of difficulty, the teacher can guide them with a question such as: “Can you imagine an experiment in which we pull on a plate to move it, either, in a progressive way, or, in a sudden movement, in jolts?"
The pupils imagine a device which quite easily interferes with the movement of the plate, (for example, velcro or double sided sticky tape under the plate) and thus prevents a gradual shift.

Research (experimentation)

The experiment, produced collectively, or by a group, is rather simple:
- Two wooden rafters are placed (or any other rather heavy object, on which a hook can be fixed) on the table.
- One or more rubber bands are attached to the hooks (depending on their strength) on these rafters, so as to be able to pull them.
- Under one of the rafters, stick on velcro or double sided sticky tape, in order to increase friction with the table.
- A container filled with water, or objects piled up in balance, are placed on the rafters so as to be able to detect the tremor (the objects fall, waves appear in the container…).
When we pull on the rubber band, parallel to the table, both rafters behave differently:
- Done case (weak friction), the rafter moves easily, without jolts, and there is no vibration (the objects placed on top do not fall).
- DIn the other case (stronger friction), the rubber band initially lengthens without moving the rafter (phase of energy accumulation), then the rafter moves suddenly (phase of rupture which releases the accumulated energy in the form of vibrations). Balanced objects fall.

Scientific note
OWe can also make the manipulation with only one rafter and vary the support. On a smooth surface (table), there is no jolt because the rafter slips easily, while on a rough surface (concrete, gravel…), the movement is in jolts.


Grade 4 of Stéphanie Barbosa (Verniolle)

Pooling and conclusion

The preceding experiment showed that a vibration is created when there is a violent movement of the object in relation to the surface. When the movement is progressive, there is no jolt. The teacher ensures that the pupils properly establish the link between this model and reality. The conclusion can be:
The tectonic plates are moving against each other. When this movement is regular, without jolts, it does not create a seism. But when this movement is constrained for one reason or another, accumulated energy is released violently, by a sudden movement of the two plates, which creates a seism.
The place where this break or this displacement occurs is called the focus. The focus of a seism can be more or less deep (10 to 700 km).
The class then reconsiders the definition of the epicentre established in session 2-3, by explaining that the epicentre is the point, on the surface, which is vertically above the focus.
These two definitions, as well as the diagrams of the experiment and the conclusion are noted in the scientific notebook.

 


Session 2-6: How to detect an earthquake? Making a seismograph

duration

1 h 45, en 2 fois

material

For each pupil:
- a photocopy of sheet 24

For each group:
- materials necessary to build the seismograph (see examples below)

objectives

The vibrations of the ground can be measured using a seismograph

skills

- Handle and experiment, formulate a hypothesis and test it, debate
- Express the results of a measurement or research using scientific vocabulary verbally and in writing
- Locate explicit information in a text

main Subject

Sciences, technology

vocabulary

Seismograph, seismogram

This meeting takes place in two separate sessions, to allow pupils to gather the materials required:
- 1st part: Design of the seismograph, list of the necessary materials
- 2nd part: Build and test the seismograph, then documentary study
The teacher can lead the two parts one after the other, as long as a lot of material has been planned to answer the very varied needs of pupils.

Initial question

After having reviewed what was seen previously (a seism is created by a violent movement of the tectonic plates, this vibration is propagated and can cause damage), the teacher asks the pupils how a seism can be detected, or, more simply, how one can know that a seism takes place. He can question them on the senses involved (we feel with the body, we see objects moving or falling, we hear these objects move or vibrate).
Pupils then think in small groups about an experimental device to detect an earthquake. It is then a question of designing and manufacturing a seismograph. The pupils must provide a diagram illustrating the operation of their seismograph, as well as the list of the materials necessary to build it.


Grade 4 of Anne-Marie Lebrun (Bourg-la-Reine)

Pedagogical notes
- For the moment, the teacher does not specify if it is simply a matter of detecting that an earthquake took place, or if it is also a matter of measuring its “strength”, or if it is a matter of keeping a record of it (for example, written). These various aspects will be discussed when the proposals of the various groups are compared.
- In order not to stifle the creativity of the pupils by directing their designs, it is important not to show them the available material (if it has already been gathered but to also explain to them that they have the right to imagine any device, provided that the material can be obtained easily (availability and cost). If some of the proposals are too fanciful or impractical, they will be corrected retrospectively.

Pooling

The various proposals are displayed and compared. The pupils can propose very varied devices. Their common point is that there must always be something mobile (suspended, in balance…) likely to move at the time of a vibration. The simplest devices make it possible to detect that a seism took place, but does not keep a durable record of it. Some barely more complex devices allow to keep a record of it, or to even measure the strength and direction of the oscillation (see examples of designs below).
The materials needed are discussed, if it is not available and cannot be gathered for the next time, the seismograph is modified in order to adapt to the available material.

Build

Each group of pupils receives the material necessary to the realization of their seismograph, builds it and then tests it.
The proposals being very variable from one class to another, and from one group to another, we give some examples of the main designs (balance, magnets, water…), knowing that, for each main one, there are many variations.

Around balance

 

Grade 3/4 of Francis Bachelet and Corinne Dauchart (Rosheim)

Objects are placed in balance, and fall when the table is shaken.

Using water

 

Grade 4 of Anne-Marie Lebrun(Bourg-la-Reine)

A bucket is filled with water. Holes are drilled just above the surface of water, all around the bucket. The jolt creates a wave, which makes water enter the holes. Water is collected in containers (a container for each hole). Its direction can even be deduced from the oscillation (by observing, afterwards, which containers are flooded).

Using magnets

 

Grade 4 of Anne-Marie Lebrun(Bourg-la-Reine)

Two magnets are suspended on two strings, at a distance in such a way that they stick to one another as soon as the table is jolted.

Writing records

 

Grade 4 of Anne-Marie Lebrun(Bourg-la-Reine)

A felt pen is hung from a hanger and marks a paper sheet. In the event of jolt, a trace in the form of zigzag can be seen. This device can be very easily improved (by ballasting the felt pen so that it is always in contact with the sheet, by using a roll of paper which turns, rather than a sheet…).

Pedagogical note
Many other devices can be imagined, such as for example:
- an object hanging from a spring (the spring will start to oscillate) ;
- small bells hanging from a string (which will tinkle) ;
- The strength of the jolt can also only be measured with balls and perforated boards (with more or less large holes): if the jolt is weak, only the balls resting on a very small hole will fall, if the jolt is strong, all the balls will fall;
- a movable metal rod which when subjected to a jolt, will come into contact with an electric circuit, and complete it (a bulb lights up, a buzzer sounds…).

Documentary study

The teacher distributes sheet 24 describing the first seismograph, invented in China in 132 AD (Han dynasty).
After an individual reading of this sheet, the teacher leads a collective discussion intended to make sure that the pupils properly understand the way this seismograph works. The class can then search for the similarities and differences between this device and those made during this session.
The pierced water bucket is rather similar to the Chinese seismograph, but the disadvantage of water is twofold:
- It does not make noise, as opposed to the metal marbles (hence the seismograph would be checked constantly to see whether it has recorded something).
- It evaporates with time, making the seismograph ineffective.
The end of this documentary sheet shows what a modern seismogram (recording carried out by a seismograph) looks like. This part has already been discussed, but will be studied again during the next session.

Written records

Each pupil describes his/her seismograph in his scientific notebook.

Extension

The class can visit a museum such as "arts & crafts" in order to observe various types of seismographs.

 


Session 2-7: Magnitude and intensity, comparison of the Richter and MSK scales

duration

1 h 15 min

material

For each pupil:
- sheet 24, already used in the previous session
- a photocopy of sheet 25

For the class:
- computer room

objectives

- The extent of the vibration created at the focus is measured on the Richter scale. One speaks of magnitude.
- The Richter scale is an open scale, but a seism of a magnitude greater than 10 or higher has never been seen.

skills

- Express the results of a measurement or research using scientific vocabulary verbally and in writing
- Read a digital document

main Subject

Sciences

vocabulary

Magnitude, Richter scale

Pedagogical note
This session is used to introduce the Richter scale and as well as to make an interim assessment. For this purpose, the multimedia animation “the earthquakes” is very useful, because it helps to understand the difference between magnitude and intensity.

Initial question

The documentary card used at the time of the previous session shows a particular seismogram (recording of a seismograph), of the seism which occurred in Haiti on 12th January 2010.
The teacher asks the pupils what corresponds to the amplitudes of the recorded oscillations.
They correspond to the amplitude of the jolts themselves, i.e. to the energy released during the seism: a weak earthquake causes weak jolts (and the traces of low amplitude on the seismogram), while a strong earthquake causes big jolts, which appear as strong swings on the seismogram.
The teacher explains that the energy released by an earthquake is called the magnitude… that it is measured on a different scale than that seen previously: the Richter scale.

Pedagogical note
- Many seismograms are found on the website http://www.edusismo.org
- The analysis of this seismogram makes it possible to note that a seism gives rise to several jolts. Some are very fast (tight lines, on the left) and others slower: this observation will be useful at the time of Session 2-10.

Documentary research

Each pupil receives a photocopy of sheet 25, which represents the Richter scale and compares the released energy of earthquakes of various magnitudes with other phenomena (explosion of an atomic bomb for example).

Pooling

After a few minutes of reading, the teacher questions the pupils collectively:
- What does the magnitude of an earthquake correspond to?
- Can an earthquake have several magnitudes? (the documents of session 2-1 help us answer that an earthquake only has one magnitude)
The teacher ensures that everyone understands that there is an enormous difference between an earthquake of magnitude N and another of magnitude N+1. A variation of 1 magnitude means a factor 32 in energy; a variation of 2 magnitudes means factor 1000!
PFor example, the teacher can be interested in magnitude 6, very vivid for the children (the energy released is the same as that of the explosion of the Hiroshima bomb). He asks what corresponds to magnitude 7. The answer is: 32 atomic bombs. He then asks what corresponds to magnitude 8 (answer: 32 X 32 = 1 024 atomic bombs), then magnitude 9…
The teacher ensures that the pupils understand the difference between magnitude (Richter scale), which is absolute and measures the "raw" energy of the earthquake, and intensity (MSK scale), which measures the extent of the damage and depends on the place of observation.
So as not to confuse the two, these two quantities are noted in different ways:
- the magnitude (Richter) is noted in Arabic numerals;
- the intensity (MSK) is noted in Roman numerals.

Multimedia animation: mid-term assessment

The end of this session is based on a multimedia animation, produced by La main à la pâte and Universcience.
LThe pupils are divided into small groups, ideally in pairs, each group having a computer at its disposal, with the animation uploaded onto the screen.
The interactive animation proceeds in several phases:
- Initially, the pupil can vary 3 parameters (depth of the focus, magnitude on the Richter scale and geographical area).
- Then, an earthquake can be started and the damage caused visualized.
- Finally, information is received about the required action in the event of an earthquake.

Animation « Earthquakes »

Pedagogical note
We can make the pupils understand that an earthquake is never “by itself”, but followed by several aftershocks, some arriving a few minutes after the main seism, others several days later. For that, an animation relating to the earthquake which occurred in Japan in March 2011 can be viewed. This earthquake had, over a few weeks, several hundred aftershocks. The site http://www.japanquakemap.com/ makes it possible to see the aftershocks scroll (tip: accelerate the course of time). After having viewed the animation, the class goes back to what was seen since the beginning of the session: what a seism is, how it is created and spread, how it is measured…

Conclusion

The class develops a collective conclusion, which is noted in the scientific notebooks. For example:
An earthquake can be described by two scales. Its magnitude, on the Richter scale, measures the energy it releases. Its intensity, on the MSK scale, measures the local damage. There are thousands of earthquakes each day. But earthquakes with a magnitude higher than 8 are rare. Beyond 9, they are exceptional.

 


Session 2-8: Can we predict earthquakes?

duration

1 hour

material

For each group:
- documents to be prepared in advance by the teacher (see below)
- a photocopy of sheet 26

objectives

We cannot predict earthquakes, but we know the areas at risk

skills

- Express the results of a measurement or research using scientific vocabulary verbally and in writing
- Know the various physical geographical features, locate them on maps of different scales

main Subject

geography

Initial question

The teacher asks the class collectively if it is possible to predict when and where an earthquake will take place.
The teacher explains that the answer to the question “when” is negative: the occurrence of an earthquake cannot be predicted.
On the other hand, the class has already seen, during session 2-4, that earthquakes were not located everywhere. The past seismic activity of an area can thus be used to assess future seismic risk.

Documentary research

The teacher gets, via the site www.sisfrance.net, the list of earthquakes recorded in their area. He or she gets in fact two lists. First of all, the list of earthquakes felt by some people (intensity higher than 3), and then that of earthquakes which caused minor damage (intensity higher than 6).

 

To do this, from the home page of the site www.sisfrance.net, click on an area. On the right a form then appears. The results can be filtered, by ignoring for example all the earthquakes too weak to have had a notable effect (tip: put a minimum intensity of 3.0), and finally confirm. Then do the same thing with another threshold value of intensity (for example, 6.0). See screenshot hereabove.
A table showing various earthquakes with their corresponding dates is acquired. For example:
- for the region of Ariège, more than one hundred earthquakes with an intensity higher than 3 can be found, but only 5 with an intensity higher than 6;
- Paris has had a dozen earthquakes with an intensity higher than 3, but none with an intensity higher than 4.

Scientific notes
There is a small error on the site www.sisfrance.net: the intensities are noted in Arabic numerals, whereas the rule requires that they be written in Roman numerals so as not to confuse them with magnitude. The document provides the epicentres… but earthquakes whose epicentre is located in another area can sometimes be felt. The lists are therefore not exhaustive.

The seismic risk in France

The teacher distributes a map of the seismic risk to each pupil (sheet 26), or prints it in an A3 or superior format in order to display it in the classroom. This document evaluates the current and future risk, while the previous documentary research made it possible to note past disasters.

Pedagogical note
Here can be found an Excel table which was created by the ministry for Sustainable Development, and gives the seismic zoning of the 36 721 French counties, i.e. the characterization of the risk: very weak, weak, moderate, average, and extreme.

The teacher prompts a collective discussion with the goal of observing that in France all regions experience earthquakes. In the majority of cases, they are very weak earthquakes which do not cause much damage. Certain regions, however, sometimes experience more intense earthquakes, and are regarded as more risky. In particular, regions of the the Pyrenees chain and the Alps, as well as Guadalupe and Martinique.

Written records and conclusion

This observation is noted in the scientific notebook, accompanied by the data on the seismicity of the school's geographical region.

 


Session 2-9: What to do in case of earthquake?

duration

1 hour

material

For each pupil:
- a photocopy of sheet 27

objectives

In the event of earthquake, one can be protected by simple actions

skills

- Formulate an assumption
- Mobilize knowledge in different scientific contexts
- Express the results of research using scientific vocabulary verbally and in writing

main Subject

Sciences

Initial question

The teacher reviews what was learnt during the previous session (it is not possible to predict the occurrence of an earthquake). He then asks the question: “If one lives in an area at risk, is it still possible to be protected?"
The pupils work in pairs and write their ideas in their scientific notebooks.


Grade 3/4 of Francis Bachelet and Corinne Dauchart (Rosheim)

Pooling

The collective discussion makes it possible to identify two main ideas:
- Buildings (where to build, how to build…).
- Behaviours (before, during, after).


If the first idea (to build to earthquake standards) is not mentioned, we can come back on what had been seen during session 2-1: the main danger (except tsunami), during an earthquake, is the collapse of the buildings. Ideas are recorded separately: they will be the subject of the next two sessions.
The rest of the session is centered on behaviors. The proposals of the pupils are very varied, and sometimes contradictory. Examples:
- get under a table
- take the car and drive far
- take refuge underground (carpark, basement…)
- se placer dans l’angle d’une pièce
- stand in the corner of a room
- move away from windows
- call the emergency services
- leave the buildings
- take shelter under trees, etc.


Some of these behaviors are suitable, others not. Before going further, the pupils must confront their points of view, while trying to reach a consensus. The teacher takes care that each one clarifies their ideas as much as possible: Is this action to be adopted as prevention (before the earthquake), during the tremor, or after? Why does this seem appropriate?
A particular point can lead to strong disagreements: should emergency services be called? For some pupils, the proposal is obvious, but not others, who highlight the fact that “this poses a problem if everyone calls at the same time”.
The point will be settled by the study of sheet 27, that the teacher distributes to the pupils. This sheet shows the actions to be adopted in the event of an earthquake occurring at the school. After a few minutes reading the document, the class collectively discusses its contents. Had we forgotten some actions? Did we make any errors? Which ones? The teacher then asks what should be done if we were surprised by an earthquake outside of school, for example at home, outdoors, or in the car.

Conclusion

The basic actions of protection in the event of earthquake are noted in the scientific notebook:
From the first tremor:
-
If inside: take shelter under a solid piece of furniture (table…) or in a doorway..
- If outside: move away from buildings.
- If in the car: stop, but remain in the vehicle.
After the first tremor:
- If in a building:
> cut off the water gas and electricity (for the adults) supplies if possible;
> leave the building.
- In all cases:
> do not telephone;
> listen to the radio;
> go to free common open spaces (park, stadium…).

Extensions
- Make a poster similar to the one distributed, but showing the actions to be taken at home (this activity is an application of the concepts seen in this session; can be regarded as a training assessment).
- Perform an exercise of the actions to be adopted by simulating an earthquake in the class, for example timing how long it takes to the exit the building after the first tremor.

 


Session 2-10: How to build resistant buildings? (1)

duration

1 hour

material

For each group:
- a thick polystyrene board (at least 4 cm)
- "rods” of various lengths, of the same material either:
– thick cardboard (for example a large calendar cut out into strips)
– wooden rods (kabob skewers)
– small vegetable crate
– metal (reglets or threaded rods)
– etc… (see Scientific note: hereafter)
- plasticine

objectives

- Buildings that are resistant to earthquakes can be built
- The height of a building is not a decisive parameter

skills

- Handle, experiment, formulate a hypothesis and test, debate
- Express, use the results of measurement or research by using scientific vocabulary in writing and verbally

main Subject

Sciences

Initial question

At the time of the previous session, the class raised the possibility of being protected from earthquakes by building buildings which resist shocks.
Now, the teacher asks students to individually think about the properties that a building should have to withstand earthquakes.

Pooling

The pupils make various proposals:
- Use very solid (hard) material… or on the contrary rather flexible ones.
- Build low buildings.
- Place buildings on shock absorbers…
We propose to begin this investigation with the “height” parameter. Because almost all the children (and many of the adults) think, wrongly, that it is preferable to build low buildings.
The class collectively thinks of an experiment which would make it possible to know if the height of a building plays a part in its resistance to seismic shocks.
Pupils can propose simple manipulations, starting from stack piles (kapla, dominos…). The downside of these proposals is that such buildings are not solid: rather than various piled up elements (which can slip easily), a single element would be needed.
For example stems of various heights can be taken, planted vertically on a support which is moved horizontally. The stems which oscillate the most are then looked at.

Scientific note
- The material used for the stems should not be too rigid (if not, there is no oscillation), nor too flexible (if not, the oscillations are too strong and the stems become deformed).
- So that the experiment goes correctly, it is necessary that the stems are firmly fixed to the support!
- Large wooden plinths (60 cm for the smallest, 1 m 60 for the largest) screwed firmly with a large rafter are ideal. But this material being rather expensive, we propose other alternatives which work well (skewers, thin straps of thick board… de 10, 20, 30 cm high planted in a piece of polystyrene…).
- To give a little mass to each stem, and also for a better visualizing of the oscillations, they can be weighed down by a piece of plasticine.

Research (experimentation)

The pupils are divided into groups and carry out the previously designed experiment (each group can have a different material: wooden or metal stems, cardboard…).


Grade 3/4 of Sylvie Vernet (Lyon)

The pupils can be required to initially seek to make the largest stems oscillate, then the shortest. Gradually, they realize that the speed of the oscillation (we do not speak about frequency at primary school) is important: if the board oscillates as slowly as possible, it can be observed that it is the highest stem which oscillates the most. If on the contrary very fast oscillations are caused, it is smallest which will oscillate the most. Progressively, the frequency which enables the intermediate stems to oscillate.

Pedagogical note
A video of this experiment is available here.

Pooling and conclusion

Collectively, it is noted that the speed of the vibration plays an important part. The fast jolts make the smallest stems oscillate, and the slow jolts the highest stems. The class establishes the link with reality and concludes from it that a low building is not inevitably safer than a high building. All depends on the speed of the vibration of the earthquake.
The teacher informs the pupils that in general, an earthquake includes multiple vibrations: certain slow, others faster. This conclusion is noted in the scientific books.

Scientific note
Actually, the high buildings are often more resistant than the houses, because they are conceived to resist violent winds. Their construction being the subject of more studies and monitoring due to more economic than physical reasons.

 


Session 2-11: How to build resistant buildings? (2)

duration

1 h 15 min

material

For each pupil:
- a photocopy of sheet 28
- a photocopy of sheet 29

For each group:
- props (boards, cards…)
- choice:
– cubes, rubber bands
– sand, a basin, large boxes or wooden rafters, metal stems
– glass bottles or drink cans (or any other cylindrical object which rolls well), cubes

objectives

- Buildings which are resistant to earthquakes can be built
- The chaining of building is effective
- On movable ground, it is necessary to build deep foundations so that the building resists

skills

- Handle, experiment, formulate a hypothesis and test, debate
- Express and use the results of measurement or research by using scientific vocabulary in writing and verbally

main Subject

Sciences

Initial question

The teacher distributes sheet 28 to each pupil which shows two buildings which have undergone extensive damage following an earthquake. He starts a collective discussion intended to talk about what could happen to each of the two buildings. The first fell to the ground (problem of foundations), while the second broke (problem of cohesion of the building).
The teacher then asks the pupils how the buildings can be designed to resist earthquakes better, taking into account the two problems mentioned above. Several ideas take shape, of which the main ones are:
- Build deep foundations if the building is located on loose soil.
- Bind together the various elements of the building in order to prevent the walls from moving against each other (which leads to the collapse of the building). The pupils propose for example to surround the buildings by very solid cables.
- Place the building on a damper system (springs, wheels…).
The class collectively looks at ways of testing these proposals using experiments.

Research (experimentation)

The pupils are divided into several groups. Each group tests only one proposal.

On foundations
The group working on the foundations takes two identical objects (same size, same mass), each one representing a building, placed on a basin filled with sand (loose soil). These objects can for example be two pieces of wood, or two jam jars (filled with water or sand to weigh them down).
Under one of the two objects, stems which represent foundations are fixed (super glue, nails, screw…) One of the “buildings” thus rests on loose soil, while the other rests on a hard ground (the foundations touch the bottom of the basin).
When the basin is shaken, the building with no foundations sinks into sand.


Grade 4 of Stéphanie Barbosa (Verniolle)

On chaining
This group can carry out a very simple experiment, with kaplas dominoes, wooden cubes (even larger elements such as boxes of tissues)… and some rubber bands.
Two buildings can be built by piling up these elements. One of the buildings is surrounded by rubber bands (the chaining, or wind-bracing).
When the support is shaken, the building which is not chained breaks down very easily.
One can test various types of chaining (horizontal, vertical, transverse…).


Grade 4 of Stéphanie Barbosa (Verniolle)

On shock absorbers
The pupils propose various types of devices to insulate the building from the seismic shock: shock absorbers, wheels… These proposals could be tested if the material needed is available. An easy experiment is to place buildings on a support which itself is placed on cylinders (bottles for example). When a jolt is triggered, the support moves as a whole, and the buildings vibrate less than if they were placed directly on the ground.


Classe de CM1 d’Hélène Gaillard (Paris)

Pedagogical note
Videos of these experiments are available here.

Pooling and conclusion

After having organized the pooling of the results of the various experiments, the teacher distributes sheet 29to the pupils, which describes some elementary rules of earthquake resistant construction.

Scientific note
This document is not intended to be exhaustive, but only to identify the parameters which are most important and which, moreover, can be tested experimentally in primary school.

Then he reviews the first session, during which the pupils had noticed that an earthquake of the same magnitude could have completely different effects depending on the context (earthquake-resistant buildings, preparation of the population, etc.).
The class writes a collective summary which is noted in the scientific books.

Extensions
Produce a model of earthquake-resistant building reviewing all the studied parameters
Learn about the types of constructions around the school, as well as the school itself, if one lives in a seismic region.
Study the solutions adopted in various countries to guard from seismic risk, in particular to discover other principles of earthquake-resistant construction (materials, the shape of the buildings…).

Multimedia extension

The last multimedia animation created for this project is a quiz, where some questions deal with seismic risk.

 

 

 

 

Project partners

La main à la pâte Foundation ESA