Mecânica e máquinas simples · GCSE Physics Topic 5
Simulador de pressão atmosférica e barômetro de Torricelli
Simulador de pressão atmosférica e barômetro de Torricelli: coluna de mercúrio
- No navegador
- Sem cadastro
- Dedução ao vivo
- Modo projetor
- Folha de exercícios A4
Janela de simulação 3D● 60 FPS
Variáveis de controle do experimento
kPa
°
cm
Deduções e métricas em tempo real
Altura vertical h
--
Comprimento da coluna inclinada L
--
Estado do vácuo superior
--
Limite de elevação da água pelo pistão
--
Dedução de fórmulas em tempo real
Fórmula fundamental:
--Substituição de valores:
--Estado físico: --
Exemplos clássicos e armadilhas de exame
Worked Problem
Problema: In a Torricelli experiment tilted at 30°, how do vertical height and column length change?
Derivação passo a passo:
- Vertical height is determined by atmospheric pressure and remains 760mm; column length increases to 760/cos(30°) ≈ 877.6mm.
Worked Problem
Problema: If water replaced mercury in Torricelli experiment, how tall is the water column? Can a piston pump lift water 15m?
Derivação passo a passo:
- Water column h = p/(ρg) = 1.013*10^5 / (1000*9.8) ≈ 10.33m. Piston pumps rely on atmospheric pressure and cannot exceed 10.33m.
Folha de investigação em aula e exercícios
Q1. Variant 1: If a bubble of air leaks into the top Torricellian space, does the measured pressure read high or low?
Answer Key: Reads low! Trapped air exerts downward pressure p_air, so mercury column ρgh = p0 - p_air < p0.
Q2. Variant 2: Carrying a Torricelli barometer to a mountain peak, how does the mercury column change?
Answer Key: It drops lower. Air density decreases with altitude, lowering atmospheric pressure and supported mercury height.
Q3. Variant 3: What force pulls apart two 30cm diameter evacuated Magdeburg hemispheres? (p=10^5 Pa)
Answer Key: Effective cross-section area S = πr² = 0.0707 m². Pull force F = p*S = 10^5 * 0.0707 ≈ 7070N.
Perguntas frequentes e erros comuns
Why doesn't mercury fountain out when the tube top is pierced?
Liquids fountain only if internal pressure exceeds external pressure. The top is a vacuum (0 Pa). Piercing lets 101 kPa air rush in, letting gravity drop the mercury.
Does using a wider glass tube change mercury height?
No! Hydrostatic pressure p = ρgh depends solely on density ρ and vertical height h, independent of cross-sectional area.
Does slightly lifting the tube change the mercury elevation difference?
No! The vertical elevation difference between column top and basin level remains 760mm. The top vacuum space expands.
Can astronauts drink with straws in space?
Inside a pressurized space station, yes; in the vacuum of outer space, no, because there is no atmospheric pressure to push liquid up.