Who controls the ups and downs

Hefei Science Museum Innovation Exhibits Deepening Design and Production Service Project Exhibition 5- Who Will Lead the Rise and Fall

Exhibition size: approximately 3 x 1.8 x 2 meters (width x depth x height)

Knowledge points:

Density is one of the characteristics of matter, and every substance has a certain density. The density of different substances is generally different. Generally speaking, no matter what substance or state it is in, its density will also change correspondingly with changes in temperature and pressure.

Participation method:

Mechatronics interaction, consisting of 5 interactive modules.

(1) Splitting and merging

On the exhibition stand, there are two types of colorless and transparent liquid bottles with different densities, and two floating blocks with different densities are suspended at the interface between the two liquids. Shaking the bottle up and down, the floating blocks that were originally suspended in the middle of the liquid, one rises to the surface of the liquid and the other sinks to the bottom of the liquid; Let it rest for a while, and the floating block will return to the middle of the bottle, presenting a suspended state.

(2) Bidirectional floating sinker

A sealed water tank, multiple floats with different densities, and pressure regulators (syringes) are installed on the exhibition stand. The audience controls the buoyancy of the float by squeezing and pulling the pressure regulator (syringe). When the pressure in the water tank increases, the air column inside the floating sinker is compressed and its volume decreases, and the density of the floating sinker increases and sinks; When the pressure in the water tank decreases, the air column inside the float and sinker expands and increases in volume after losing pressure, and the density of the float and sinker decreases and increases. By controlling the changes in pressure, it is possible to achieve the sequential rise or fall of floaters with different densities.

(3) Bubble shipwreck

Install water tanks, bubble generation devices, and small boats on the booth. After the audience presses the ventilation button, the bubble generation device will release a large amount of bubbles into the water tank, and the small boat floating on the upper part of the water tank will sink to the bottom. When a large amount of air is mixed in the water, it becomes a mixture of water and air, and the density of the mixed liquid is lower than that of the small boat. The small boat gains less buoyancy and sinks to the bottom of the water.

(4) Hot air balloon weighing

Hot air balloons, heat sources (incandescent lamps), and electronic scales are installed on the booth. The audience lights up the light bulb through a button, which heats up the surrounding air. According to the principle of thermal expansion and contraction, air is expelled from the hot air balloon, reducing its overall weight. The weight changes displayed on the electronic scale reveal the air inside the hot air balloon. As the temperature increases, the air density decreases, causing the hot air balloon to rise.

(5) True and False Crown

Two transparent water pools and scales are set up on the booth. Two crowns are hung at each end of the balance. The audience observed the balance and found that the two crowns were the same weight. Rotate the handwheel to fully immerse the crown in water, only to find that the balance is no longer balanced and the water in the pool rises at a different height.

Design and process requirements:

Split and Split: Composed of a bracket, spring, bottle, two incompatible liquids, and two floats with different densities. The selection of two liquids is reasonable, incompatible with each other and of unequal density. They approximate the refractive index of light, ensuring that the boundary line cannot be distinguished by naked eye observation while achieving upper and lower layering. Two different densities of small balls inside the density bottle are precisely calculated for volume and mass, and then CNC precision machining is performed to ensure quality.

Bidirectional floating sinker: composed of a sealed water tank, pressure regulating device, water, floating sinker, rubber plug, etc. The water tank is transparent, sturdy and durable, with a reasonable sealing design and a convenient water change feature. The pressure regulating device is designed reasonably, which can accurately regulate the pressure inside the water tank and is stable and durable.

Bubble shipwreck: Exhibitions consist of a water tank, a small boat model, a bubble generation device, buttons, and water. The small boat should ensure that the upper part of the hull is in a water out state under normal conditions. The bubbles generated by the bubble generation device are fine and dense, ensuring a significant sinking effect.

Hot air balloon weighing: composed of sensitive electronic scales, hot air balloons, light bulbs, and buttons. The waiting time from the audience pressing the button to the hot air balloon starting to rise should not exceed 15 seconds. The design of bulb power and position is reasonable and will not cause discomfort to the audience's eyes. There are suitable protective devices that will not burn the audience.

True and False Crown: Composed of acrylic transparent water tank, balance, crown, and handwheel. The balance is sensitive, not easily damaged, and has a calibration design. The crown is made of metal material with a gold-plated surface, which does not change color due to frequent immersion in water.

Other requirements:

True and false crowns must be equipped with educational activity props such as "Gold Nuggets", "Crown 1", "Crown 2", and "Crown 3". Crown 1, 2, and 3 have the same appearance and completely equal quality. The volume of 'Crown 1' is exactly the same as that of 'Gold'; Crown 2 is equipped with a detachable impurity module, which has a volume larger than that of a gold nugget; Crown 3 is equipped with a concealed chamber structure that can be connected and sealed to the outside world, with a volume larger than that of a gold nugget.