A vela que levanta a água (a água que sobe na garrafa) (EXPERIÊNCIA)

Summary

In this engaging scientific experiment, the presenter demonstrates how water can rise due to a simple yet fascinating principle. The experiment starts by placing a lit candle beneath a glass container filled with colored water. As the candle burns, the traditional explanation is challenged: instead of the air being consumed by the flame, a decrease in air temperature and pressure leads to the water rising into the container. A second experiment using hot water further confirms this new scientific explanation, highlighting the competition between internal and atmospheric pressure. The video explains this phenomenon in an educational and visually appealing way.

Takeaways

• 😀 The experiment demonstrates how a candle can make water rise in a bottle, showing the relationship between air pressure and temperature.
• 🔥 The experiment uses a candle, water, a glass bottle, and food coloring to make the water rise for a clearer visual effect.
• 📉 The original explanation for the phenomenon was that burning the candle consumes oxygen, creating a vacuum that pulls the water up, but this explanation was disproven.
• 🧪 Scientists now understand that the heat from the candle causes the air inside the bottle to expand, lowering its pressure.
• 🌡️ As the air inside the bottle cools down, its pressure decreases, and the atmospheric pressure outside pushes the water inside the bottle.
• 💨 The new explanation emphasizes that both carbon dioxide and water vapor are produced by the burning candle, contributing to the change in air pressure, not just the consumption of oxygen.
• 💡 The principle of air pressure and temperature is demonstrated clearly by the water's rise in the bottle.
• ⚗️ The second experiment shows the same effect without using fire, simply by heating the bottle with hot water.
• ⏳ The second experiment occurs more slowly because hot water heats the air inside less efficiently than the flame of the candle.
• 📚 Additional scientific articles and videos are provided in the description for further exploration of the experiment and the historical confusion surrounding its explanation.

Q & A

What materials are needed for the experiment?

You will need a dish, a candle, a glass bottle (such as a jar or a cup), water (preferably dyed for better visibility), and a heat source to light the candle.

Why is it recommended to use dyed water in the experiment?

Dyed water makes the rising water inside the glass bottle more visible, helping viewers better understand the effect.

What is the first, incorrect explanation for why the water rises in the bottle?

The old explanation suggests that as the candle burns, it consumes the oxygen inside the bottle, reducing the gas volume and causing the water to rise.

Why is the old explanation about oxygen consumption incorrect?

The burning candle not only consumes oxygen but also produces carbon dioxide and water vapor, which take up space inside the bottle. Therefore, the decrease in oxygen alone cannot account for the water rising.

What is the correct scientific explanation for the water rising inside the bottle?

The correct explanation is that when the bottle is placed over the candle, the air inside becomes heated and expands. As the flame dies down, the air cools, and its pressure decreases. The outside atmospheric pressure pushes the water into the bottle as a result of this pressure difference.

What happens when the temperature of the air inside the bottle decreases?

As the temperature of the air inside the bottle decreases, the air contracts, causing the pressure inside the bottle to drop. This lower pressure inside competes with the higher atmospheric pressure outside, causing the water to rise into the bottle.

How does the second experiment using hot water compare to the first experiment with a candle?

In the second experiment, hot water is used to heat the air inside the bottle instead of a candle. This demonstrates the same principle, but the process occurs more slowly because hot water does not heat the air as quickly as the flame of a candle.

What role does atmospheric pressure play in this experiment?

Atmospheric pressure plays a key role by pushing the water into the bottle when the air inside the bottle cools and its pressure drops, allowing the external pressure to 'win' the competition.

How does the cooling of the air inside the bottle affect the experiment?

As the air inside the bottle cools, its volume decreases, which lowers the internal pressure. This allows the higher atmospheric pressure outside to push the water inside the bottle, causing the water to rise.

Why does the second experiment occur more slowly than the first one?

The second experiment occurs more slowly because the hot water inside the bottle heats the air less rapidly than the flame of a candle, resulting in a slower cooling process and a more gradual decrease in pressure.