The 13th IYPT

Budapest (Hungary), June 8th - 15th, 2000
Homepage of the 13th IYPT

The Problems of the 13th IYPT

These are the problems formulated by the IOC (International Organising Committee) for the 13th IYPT:

1. Invent by yourself

Suggest a contact-free method for the measurement of the surface tension coefficient of water. Make an estimation of the accuracy of the method.

2. Tuning fork

A tuning fork with a resonant frequency of about 100 Hz is struck and held horizontally, so that its prongs oscillate up and down. A drop of water is placed on the surface of the upper prong. During the oscillation of the tuning fork standing waves appear on the surface of the drop and change with time. Explain the observed phenomena.

3. Plasma

Investigate the electrical conductivity of the flame of candle. Examine the influence of relevant parameters in particular the shape and polarity of the electrodes. The experiments should be carried out with a voltage not exceeding 150V.

4. Splash of water

Measure the height reached by splashes of water when a spherical body is dropped into water. Find a relationship between the height of the splashes, the height from which the body is dropped, and other relevant parameters.

5. Sparkling water

Bubbles in a glass of sparkling water adhere to the walls of the glass at different heights. Find a relationship between the average size of the bubble and their height on the side of the glass.

6. Transmission of signals

Using a bulb construct the optimum transmitter of signals without any modulation of the light beam between the transmitter and the receiver. Investigate the parameters of your device. The quality of the device is defined by the product of the information rate (bits/sec) and distance between transmitter and receiver.

7. Merry-go-round

A small, light, ball is kept at the bottom of a glass filled with an aqueous solution and then set free. Select the properties of the solution, so that a moving up time of several seconds is achieved. How will this time change, if you put your glass on the surface of a rotating disk?

8. Freezing drop

Drops of melted lead or tin fall from some height into a deep vessel filled with water. Describe and explain the shape of the frozen drops as a function of height of fall.

9. Radioactivity

Use efficient methods to collect as much radioactive material as you can in a room. Measure the half-life of the material you have collected.

10. Liquid fingers

When a layer of hot salt solution lies above a layer of cold water, the interface between the two layers becomes unstable and a structure resembling fingers develops in the fluid. Investigate and explain this phenomenon.

11. Throwing stone

A student wants to throw a stone so that it reaches the greatest distance possible. Find the optimum mass of the stone that should be used.

12. Tearing paper

Tear a sheet of paper and investigate the path along which the paper tears.

13. Rolling can

A can partially filled with water rolls down an inclined plane. Investigate its motion.

14. Illumination

Two bulbs, 100 and 40 watts, respectively, illuminate a table tennis ball placed between them. Find the position of the ball, when both sides of the ball appear to be equally lit. Explain the result.

15. Cooling water

Two identical open glasses, filled with hot and warm water, respectively, begin to cool under normal room conditions. Is it possible that the glass filled with hot water will ever reach a lower temperature than the glass filled with warm water? Make an experiment and explain the result.

16. Coloured sand

Allow a mixture of differently coloured, granular materials to trickle into a transparent, narrow container. The materials build up distinct bands. Investigate and explain this phenomenon.

17. A strange sound

Pour hot water into a cup containing some cappuccino or chocolate powder. Stir slightly. If you then knock the bottom of the cup with a teaspoon you will hear a sound of low pitch. Study how the pitch changes when you continue knocking. Explain the phenomenon.

General comments on the problems

The problems for the 13th IYPT are not as various as the problems for the 12th IYPT were. Lots of them concern similar physic disciplines (in particular: fluid dynamics, solid state physics,...).
The division into the three groups mentioned is not so easy. There is only one problem concerning an "every-day-life"-effect: no. 17 "A strange sound": I recommend all people who often drink cappuccino or hot chocolate to try it. I'm sure you can surprise some others with the strange effect.

Lots of the other problems require basic science knowledge in order to be completely understood.
Even when they do not seem so interesting to the layman, some of them are quite fascinating.

In addition I have to mention that I consider the problems for the 13th IYPT more interesting, but also more difficult than the problems of the 12th IYPT, which is perhaps due to the fact that our preparations work was much more interesting and organised but also more difficult because of our experiences.

If I had to mention 3 favourite problems I would say: no. 6 "Transmission of signals", no. 3 "Plasma", no. 7 "Merry-go-round" (in that order).

Chronology of the preparations work

It was on the 28 of October 1999 when we downloaded the problems of the 13th IYPT. That time we wanted to be more organised, with weekly meetings, and with the goal to prepare an efficient IYPT report. We had learned from our mistakes from the previous year.

From October until Christmas we had a weekly meeting where we did various experiments and theoretical work. After the Christmas holidays our efforts stalled a bit because we were working on an UNESCO physics project which was time-consuming.
Our teacher, however, continued to keep contact with different science institutes and experts.
The AYPT 2000 was scheduled for April 23-24. For that year 10 problems of the 17 had been preselected for the AYPT so that there was not too much work to do.
Moreover, we learned that 2 foreign teams had been invited to the AYPT (one from Italy, one from Ukraine).

So in the weeks before the AYPT we really worked hard on the final layout of our presentations. We also prepared possible arguments for our opponences and reviews, had tactical discussions and practised our presentations so that they would really impress the jury.

That year Austria could only send one team to the international competition, so if we wanted to participate in the IYPT we had to win the AYPT. Therefore we really worked hard.

In addition to that, we had one significant problem: Normally an IYPT team consists of 5 members. Unfortunately there were only 3 members left.
So each of us had more work to do than in a 5-members team, even during the Easter holidays we had to do some work.
Finally 5 teams were competing at the 2nd AYPT in Vienna. One from the Polgarstraße school, on from the Lycee francais, one from Italy, one from the Ukraine and our team.

There were 2 fights on the program: one selective, and one final fight. We presented two reports which were very much appreciated by the jury and succeeded in winning the 2nd AYPT by 20 points.
It was a great feeling that we would be able to represent our country in the IYPT again, due to our own abilities and experiences.
The other teams did not have any students from the previous year left, so the three of us were the only experienced ones.

As I have already mentioned, we were only 3 team members. So 2 students of our choice from the other teams could accompany us to Budapest, which gave them the opportunity to participate too. On the other hand we benefited from their solutions, reports and other materials as well as from the help of their teachers and colleagues.
The fact was that we had two and a half months left until the IYPT in Budapest, but not the whole time was available for preparation because of some other scheduled events and projects.
There had been 7 problems left, which had not been preselected for the AYPT. So there was still no solution to these problems and the presentations from the AYPT had to be improved. Errors which were detected during or after the competition had to be corrected.

Several meetings in Vienna were held in order to plan further activities and to compare results.
One day we also invited some professors from the Viennese university, who were jurors in the AYPT, to help us.

Unfortunately there was not enough time left to prepare reports for all of the problems. So we finally went to Budapest in July 2000 with 11 well-prepared presentations.
Nevertheless we felt better than the year before, because our science knowledge and our English had greatly improved, especially technical terms didn't cause troubles any more, because we got more used to "science English".