1.Dynamic Hydrophobicity

When a drop of liquid impacts on a horizontally moving surface, the droplet may be reflected or not, depending on the speed of the surface.Investigate the interaction between a moving surface and a liquid drop.

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  experiment

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  experiment

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  Theory verification

I studied the splashing behavior of droplets under different conditions and conducted a semi-quantitative analysis of the effects on experimental variables, provided a qualitative explanation through theoretical analysis for why a hydrophilic surface becomes 'hydrophobic' due to motion, I observed experimental phenomena and investigated the range of variations in drop height and horizontal movement velocity thresholds. I also explored the size and functional relationship of the ratio of spreading factors

 

2.Hand Helicopter

A simple hand helicopter can be made by attaching rotor blades to one end of a vertical stick. The helicopter moves upwards when the stick is twisted at a high enough speedand then let go. Investigate how the relevant parameters affect the lift-off and the maximum height.

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  experiment

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  maximum height and radius(Theory verification)

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  maximum height and mass(Theory verification)

Quantitatively determined the critical takeoff conditions, theoretically calculated the founction of maximum flight altitude, takeoff angular velocity and wingspan. Obtained the function of flight altitude over time and conducted experimental validation by constructing the device using 3D printing.

Eddy Current Braking in Metal Discs and Its Applications:

Eddy current braking is a common phenomenon. Placing a rotating metal disc in a magnetic field generates an electromotive force due to the cutting of magnetic lines of flux, resulting in eddy currents. Under the influence of Ampère's force, the metal disc experiences a torque that hinders its motion, thereby decelerating it. In production and daily life, eddy currents lead to energy losses and waste. However, contradictions are dialectically united. Eddy currents can also be utilized to create instruments for measuring magnetic induction, which holds significant meaning in production and daily life. A metal disc is a common conductor. In this paper, we explore the impact of relevant parameters on the deceleration process of a rotating metal gyroscope in a magnetic field due to eddy currents. By applying Maxwell's equations, we explain the experimental phenomenon and apply our research results to the practical creation of a simple Tesla meter capable of accurately measuring magnetic induction.

Result:

First Prize of Electromagnetism Research Competition

Applications of Moiré Patterns in Textile Measurements:

Moiré patterns are a common optical phenomenon in daily life. Overlapping screens, wrinkled stockings, and other textiles often exhibit these ever-changing and fascinating patterns. This paper introduces an instrument for measuring the warp and weft density of textiles based on Moiré patterns. Due to the simplicity and ease of use of our experimental equipment, our research holds significant importance for measuring small distances and precision in production and daily life.

Result:

Second Prize of Optics Research Competition