Physics

Concepts of motion, forces, energy, electricity, waves, heat and other phenomena explained step by step.

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Bancada didática com circuitos de baixa tensão em série e em paralelo, lâmpadas acesas, multímetro, esquemas elétricos e caderno com fórmulas.

Physics22/09/20265 min read

Series and parallel circuits: how to calculate current, voltage, and resistance step by step

Learn how to identify each connection, calculate equivalent resistance, current, and voltage, and check the result with two low voltage examples.

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Pés sobre uma balança digital com detalhe do sensor de força e comparação visual da gravidade na Terra e na Lua.

Physics13/09/20265 min read

Does a scale measure mass or weight? Why it senses force but displays kilograms

A common scale’s sensor responds to a support force; its electronics use calibration to display a mass value in kilograms.

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Duas mãos tocam lado a lado uma placa de metal e um bloco de madeira sobre uma mesa, com um termômetro desfocado ao fundo.

Physics12/09/20267 min read

Why metal feels colder than wood at the same temperature: thermal effusivity explained

Metal and wood can be at the same temperature yet feel very different. Learn how heat flow, conductivity, and thermal effusivity shape touch — and try a simple test.

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Panela de pressão de aço inox sobre chama azul, liberando vapor pela válvula em uma cozinha com vegetais ao fundo.

Physics12/09/20265 min read

Why Does a Pressure Cooker Cook Faster? Pressure, Boiling Point and a Numerical Example

Learn how pressure raises water's boiling point, why cooking near 121 °C speeds food preparation, and what a simple energy calculation shows.

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Terra vista do espaço com o Brasil em destaque no limite entre dia e noite e um detalhe conceitual mostrando a refração da luz solar no horizonte.

Physics10/09/20266 min read

September 2026 equinox: why day and night are not exactly 12 hours in Brazil

The equinox occurs at 00:05 UTC on Sep. 23, but in Brazil it falls on the evening of Sep. 22, and sunrise-to-sunset daylight exceeds 12 hours because of refraction and the definiti...

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