Crane’s Balance

1- What idea do we have of a crane?
Authors : Hélène Merle(plus d'infos)
Muriel Guedj(plus d'infos)
Summary :
All cranes are not alike. This object of study of this module is the tower crane , not the mobile, telescopic or port cranes. This first sequence allows the expression of different representations, and possibly the draft of a construction project.
Publication : 1 February 2004
Objectives :
Procedure Goals: Bring out the children’s representations. What is a crane? What is its use? How does it work? Notional goals: Lead the pupils to think about what a crane is, what it does, and how it works.
Material :

Per pupil:
an experiment notebook per pupil; a reply-form per pupil.
Per group:
a billboard (50x60), markers, magnets, etc.

Pedagogical approach



1. Collection of individual designs (15 min)

Without having addressed the issue before, the quiz about the crane is distributed (or written on the board if you are working with experiment notebooks).

- What is a crane’s use?

- How does a crane work?

- Draw a crane as accurately as possible.

Individual work can begin. After 7 to 8 minutes, ask the children to move on to the drawing part.

Emphasize that no communication is allowed between pupils, they are asked to play the game, it is not an exercise of control... and they will communicate during the group work.

Reassure the children having difficulty in drawing: go see the children, answer their questions (while not providing any help).

Identify pupils with similar designs for the formation of work groups.

2. Group work (15 min)

Make the children exchange their drawings within the group. Make them find what is common, what is different, and what is more or less accurate.

Instructions: Draw a diagram of a crane, accurate enough to serve as a construction model.
The drawing must be done in pencil to enable to editing later.

Reporters from each group prepare to present their work. The works are displayed on the board at the end of the allotted time.

Be sure of the groups’ consistency, favor groups with the same design of the crane to affinity groups (while avoiding any risks of conflicts).

Also ensure the proper functioning of the groups, appoint a secretary from the beginning, a reporter and a donor of speech (try not to choose the leader of the group as reporter).

Put a particular emphasis on drawing in pencil, as this poster will be reused in future sessions. You may encourage captioning the diagram with a few words or a text.

3. Communication of the different groups’ works (15 min)

Each reporter presents his work (quickly) and answers questions from the other groups.

Intervene as little as possible, only to prevent going off topic, let pupils argue even if their arguments are not consistent with reality, and do not give an opinion on the posters other than those concerning the form.

Note the questions and the vocabulary used.

4. Synthesis (5 min)

To compare the proposals, identify differences and commonalities. After that, ask the pupils how to respond to these differences. (Confrontation with reality
Possibly arrange an outing to a construction site or ask the children to bring a model or documentation: posters, catalogues, web pages, newspaper articles, magazines

Word from La main à la pâte

Some teachers begin this session by stating that the goal is to build a model of a crane in the classroom, which motivates the children.

If children have very different representations of cranes (port cranes, mobile cranes, construction cranes) it is difficult to form groups. We can then go directly from the collection of designs to the communication in the classroom without going through group work, in order to avoid the representations of a single pupil being imposed on the group.  The more accurate prototypes drawings are then made AFTER seeing documents, scale models, or a real crane.



Il me semble que cette fiche n'insiste pas assez sur la fonction assignée à la grue. Dans ma classe (ceci n'apparaissait sans doute pas suffisamment dans les fiches déjà en ligne), j'avais insisté sur cet aspect. Il me semble que la première approche que l'on peut avoir face à un objet technologique, c'est son utilité. Il me paraît important de montrer que sa conception résulte de décisions humaines (par opposition à ce qui relève des sciences de la nature), répond à un objectif et de montrer en quoi les différentes parties de l'objet ont été fabriquées pour atteindre cet objectif