Lifelong Learning Programme

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Title of the Experience
A ping pong ball
Name of the teacher
Partene Doina
Country where it took place
School typology
High Secondary School
Thematic Area
Experience typology
Teaching in class
Type of contact
Description of the Experience
Experiments engage students in the activities. They provide excellent opportunities for learning by doing. The following experiment appealed to my students, who also practiced it with their friends. Slice a tennis ball into two halves. Make each half smaller than a hemisphere. Turn the hemisphere inside-out and drop it on a hard surface. The ball will snap and rebound to a height much greater than that from which it was dropped.
Work is required to turn the hemisphere inside-out and this work is stored as potential energy. As the dropped ball hits the hard surface, this potential energy is released and converted to kinetic energy, allowing the ball to rebound to a greater height.
Simultaneously drop a ping pong ball resting on top of a much heavier ball (such as a golf ball). If the balls are properly aligned, ideally the light ball will rebound to nearly nine times its original height. If three stacked balls each considerably heavier than the one above it--are dropped, ideally the lightest ball rebounds to nearly forty-nine times its original height. If two stacked balls with mass ratio of 3:1 are dropped (approximated by a baseball on top of a basketball), the bottom ball will remain dead on the floor ant the top ball will hit the ceiling.
The explanation for these phenomena involves conservation of momentum and kinetic energy.

Comments on this Teachers Experience

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Date: 2014.11.05

Posted by Sandis (Latvia)

Of course, experimentation is important to learner training. They sometimes understand the laws of physics by feeling on their skin and see them in real action.Eksperiment should be simple to understand, because complex things do not always remain in good memory. In general, the following experiments that are realized in real life, are better. There were no need such explenation on the kinetic and potential energy of the essence in this experience, but rather to explain how this experiment remains in the memory of students and whether they are well aware of the level of theory.

Date: 2014.10.16

Posted by Milena Gosheva (Bulgaria)

The exercise is a good example of the transition of potential into kinetic energy, but having a bounce of a height 9 times and 49 times larger than the original one is not understandable by the description. I assume that the balls are with very different masses and thus these numbers are estimated. I tried to do the experience myself but it did not work. May be if you can share more details of how exactly you are performing it, or post a picture it will be more easily understandable by other teachers. I think for a young physics teacher, who has never done an experiment with students in class it will be impossible to do that experiment.

Date: 2014.09.25

Posted by Amparo Viña (Spain)

Experiences are easily achievable in the classroom, because the materials used are easily obtainable and the cost is very low. Whenever practical examples help to understand the theoretical concepts, and from this point of view, both experiences are applicable to explain both phenomena. If we consider these experiences relevant to explain these physical phenomena.
Students wake them forward to conducting this type of practice, the problem is that you can’t always use practical examples to explain all physical phenomena, although this is not the case. It is a possible solution to the lack of student motivation. In past courses while teaching Physics I made a similar experience to that detailed in the first experience, and currently I teach specialty chemistry.


Dissemination Seminar in Florence

31 October 2015 The seminar has been held in ITIS “A. Meucci” one of the schools involved within Goerudio project activities. Its main aim was to promote the results of the project toward a broad sample of stakeholders even overcrossing the number of people directly involved in the production of project outcomes. This purpose has been totally achieved especially thanks to the participation of students and teachers coming from different schools or from other classes instead of those ones directly involved within the project activities.