Show'n'Tell: Hydrostatic weighing & spring pendulum

[Golova1111]

Hello!
I am the founder of the "Quantum Lion", a Ukrainian school physics education initiative.

Because of Russia’s ongoing aggression against Ukraine, education in Ukraine in many regions is significantly disrupted. Every 7th school in the country is somehow damaged and every 30th is completely destroyed [1]. The educational system is adapting, yet still only 64% of students now attend school in person, others are studying in hybrid mode (13%) or fully online (22%) [2]. Combined with the COVID-19 education disruption of 2020–2021, this has led to severe learning losses among Ukrainian children.

That's why we had to adapt the processes and develop new online tools for online education.

During 2025, we adapted 2 existing PhET simulations for the needs of Ukraine educational program:

1. Hydrostatic weighing
   Link: https://vlabs.kvantylion.com/static/vlabs/hydrostatic_weighing/hydrostatic_weighing_uk_kvantylion_v1_1.html

Reasons:

Existing "Buoyancy" simulations allow us to cover some of Ukraine's curriculum needs, e.g. conditions of buoyancy lab. However, one of the tasks of the 🇺🇦 program is to do the Hydrostatic weighing lab. While technically we can do this using "Compare" or "Explore" tabs, the big disadvantage is that all the answers are already visible.

So we restrict the simulation environment: we left only one screen, hid the blocks volume / mass info, forbade moving the weight in the fluid, and added the density table at the top of the screen. We released the simple video instruction and the lab template and came up with 20 task variants for students (to reduce cheating). The lab received big popularity, we estimate ~2000 students did it last year

While we understand that our derivative simulation might not meet the PhET-philosophy to create an open-world simulation and restrict the student as little as possible (to embrace curiosity and creativity), we also need such stricter scenarios as well

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2. Spring pendulum
   Link: https://vlabs.kvantylion.com/static/vlabs/spring_pendulum/spring_pendulum_uk_kvantylion_v1.html

Reasons:

The physics of this lab is based on the existing "Masses and Springs", while the visuals are partly based on "Hooke's Law" simulation.

The existing Masses and Springs simulation has a big issue. The question is that in the 🇺🇦 curriculum, a spring pendulum is defined as horizontal (so we define it as a horizontal spring with one side connected to the wall and a trolley on the open side). This gives students a better understanding of physics and simplifies the math behind it (as we no longer need to account for the gravitational force of the trolley anymore, it is always compensates with the normal reaction force). Generally, this is how this topic is taught in the Eastern European school physics tradition.

This simulation was done with significant support from modern AI tools (Copilot and others), which allows me to create it with only basic knowledge of JS but with a general computer science background.

In this case, we went a step further and added a separate screen with the test where 30 task variants are already created, and the student's goal is to determine the mass of the trolley and the spring coefficient.

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If this project caught your interest or feels relevant to what you do, we’d be very happy to talk. We’re open to collaborations, sharing our materials (including repos), adapting simulations, and preparing English versions or additional explanations if needed. Reach us at kvantylion@gmail.com

Right now, we’re also looking for grants, partners, and any kind of support that could help us grow this work and reach more Ukrainian students and teachers during the war and beyond. If you have ideas, feedback, or want to connect — please don’t hesitate to reach out. We’d truly appreciate it.

If you’d like to support Ukrainian education directly, you can also consider donating to SavED — a trustworthy Ukrainian charity that works to restore and support education in communities affected by the war.