Hong Kong Young Physicists'​ Tournament 2025: A New Milestone

Last year, I described HKYPT as a toddler. This year, our little one has advanced to kindergarten!

The transformation began before HKYPT 2024. Following HKAGE staff's visit to the 2024 Hong Kong round at Island School, I proposed transferring the organizing role to them—an idea their management team enthusiastically embraced. My heartfelt thanks to The Hong Kong Academy for Gifted Education!

Building on our 2024 IYPT experience, we enhanced HKYPT's format, requiring each team to present two problems in the final round. Despite this increased challenge for schools, we witnessed remarkable growth — 36 teams registered, compared to 14 teams in 2024!

To manage this expansion effectively, we introduced a preliminary round where teams present one of 17 problems through a 12-minute video. These problems are drawn from the International Young Physicists' Tournament (IYPT) :

1. Invent Yourself: Paper Boomerang

Make a returning boomerang from a sheet of paper by folding and/or cutting. Investigate how its motion depends on relevant parameters.

2. Air Muscle

Place a balloon inside a cylindrical net (as is sometimes used to wrap garlic) and inflate it. The net will expand and shorten. Investigate the properties of such a “muscle”.

3. Lato Lato

Attach a ball to each end of a string and connect the center of the string to a pivot. When the pivot oscillates along the vertical direction, the balls start to collide and oscillate with increasing amplitude. Investigate the phenomenon.

4. Climbing Magnets

Attach a rod assembled from cylindrical neodymium magnets horizontally to a vertical ferromagnetic rod. Limit the motion of the magnets to the vertical direction. When the ferromagnetic rod is spun around its axis of symmetry, the magnetic rod begins to climb up. Explain this phenomenon and investigate how the rate of climbing depends on relevant parameters.

5. Dancing Slinky

Twist a slinky several times and keep its bottom fixed. After releasing the top, the slinky starts to “dance” – wave-like phenomenon can be observed from the side-view. Explain the phenomenon and investigate the parameters affecting the slinky’s motion.

6. Dripping Faucet

A leaky faucet develops interesting dripping patterns, where the time between drops depends on the water flowrate. Investigate this phenomenon and study how it depends on relevant parameters.

7. Ruler Cannon

Two rulers are tightly held against each other. A round projectile (e.g. a plastic bottle cap or a ball) is inserted between them close to one of their ends. When extra force is exerted on the surface of the rulers, the projectile is ejected at a high speed. Investigate this effect and the parameters that affect ejection speed.

8. Levitating Fluid

When a container partially filled with liquid is oscillated vertically and air is injected at the bottom of the container, the fluid can “levitate”. Investigate the phenomenon.

9. Magnetic Assist

Attach one or two magnets to a non-magnetic and non-conductive base such that they attract a magnet suspended from a string. Investigate how the motion of the moving magnet depends on relevant parameters.

10. Rayleigh–Bénard convection

Uniformly and gently heat the bottom of a container containing a suspension of powder in oil (e.g. mica powder in silicon oil), cell-like structures may form. Explain and investigate this phenomenon.

11. Spring Hysteresis

Connect two identical linear springs symmetrically to a mass in a “V” shape, and apply an adjustable force to the mass. When this force is varied, the resulting motion of the mass depends on the history of changes in the applied force under certain conditions. Investigate this phenomenon.

12. Sound Versus Fire

A small flame can be put out by sound. Investigate the parameters of the flame and characteristics of the sound that determine whether the flame will be extinguished.

13. Spaghetti Accelerator

When a piece of spaghetti is pushed into a bent tube, small debris of spaghetti may be ejected from the other end of the tube at a surprisingly high speed. Investigate this phenomenon.

14. Water Bottle Rocket

Pump air into a plastic water bottle partially filled with water. Under certain conditions, the bottle is launched and flies into the air. Investigate how the acceleration during lift-off depends on relevant parameters.

15. Wailing Bowl

When you strike the side of a metal bowl containing some water, you can hear a characteristic sound. The sound changes when the water in the bowl is moving. Explain and investigate the phenomenon.

16. Wirtz Pump

A Wirtz Pump is a hollow spiral, mounted vertically. It is arranged such that one end dips below water once per revolution, while the other end (at the center of the spiral) is connected to a vertical tube. When rotated, it can be used to pump water to a great height. Explain this phenomenon and investigate how relevant parameters affect the pumping height.

17. Quantum Fingerprint

Shine laser light onto an organic polymer (eg. styrofoam). The scattered light may have a higher or lower wavelength than the incident light. Explain the phenomenon and determine what can be concluded about the molecular structure of the material from the wavelength shift.

Thanks to steadfast support from Hong Kong universities, we successfully hosted the final round for 14 teams at West Island School on February 22, 2025. Special thanks to Andrew Couch for this valuable collaboration!

The top five teams received Gold Awards and an extraordinary opportunity: one member from each team will represent Hong Kong at IYPT Sweden, held in Lund from late June to early July 2025. I'm particularly proud that HKAGE's full subsidy for team members has made this international competition accessible to all secondary school physics talents in Hong Kong!

My deepest gratitude goes to all the jurors, supervising teachers, students, spectators, West Island School and especially HKAGE for making this achievement possible.

Schools interested in HKYPT 2026 can email ypt@hkage.org.hk or visit the official page: https://www.hkage.edu.hk/en-us/article/1547 and the Instagram page https://www.instagram.com/p/DG5N1_LTBR0/