物理学 12-3理想气体的压强公式 第五版 理想气体的微观模型 (The microscopic model of the ideal gas) 力学假设 (Mechanical hypothesis) (1)气体分子当作质点,不占体积,体现气态的特性。 The gas molecules treats as the particle, it does not account for the volume, manifests the characteristic of the gaseous state (2)每个气体分子的运动遵从牛顿力学的规律; The motion of each gas molecule follows Newtonian law of mechanics 第十二章气体动理论 1/13
第十二章 气体动理论 物理学 第五版 12-3 理想气体的压强公式 1/13 (1)气体分子当作质点，不占体积，体现气态的特性。 一 理想气体的微观模型 (The microscopic model of the ideal gas) The gas molecules treats as the particle, it does not account for the volume, manifests the characteristic of the gaseous state (2)每个气体分子的运动遵从牛顿力学的规律； The motion of each gas molecule follows Newtonian law of mechanics 力学假设 (Mechanical hypothesis)
物理学 12-3理想气体的压强公式 第五版 (3)分子之间除碰撞的瞬间外,无相互作用力,分 子之间以及分子与器壁间碰撞为弹性碰撞; 般情况下,忽略重力。 Other than the moment of collision, the interaction forces between molecules are neglible, collision between gas molecules between molecules container walls can be views as complete elastic collisions, under normal circumstances, ignore gravity 第十二章气体动理论 2/13
第十二章 气体动理论 物理学 第五版 12-3 理想气体的压强公式 2/13 (3)分子之间除碰撞的瞬间外，无相互作用力，分 子之间以及分子与器壁间碰撞为弹性碰撞;一 般情况下，忽略重力。 Other than the moment of collision, the interdction forces between molecules are neglible, collision between gas molecules & between molecules & container walls can be views as complete elastic collisions, under normal circumstances, ignore gravity
物理学 12-3理想气体的压强公式 第五版 「大量分子组成的气体系统的统计假设: Statistical hypothesis of gas system composed of large quantities of molecules (1)分子的速度各不相同,而且通过碰撞不断变化着; The speed of molecules are various, are changing unceasingly through the collision (2)平衡态时分子按位置的分布是均匀的, 即分子数密度到处一样,不受重力影响; When equilibrium state the distribution of molecules according to the position is even, i. e the molecular number density is everywhere the same, distribution is not affected by gravity N dV一体积元(宏观小,微观大) 第十二章气体动理论 3/13
第十二章 气体动理论 物理学 第五版 12-3 理想气体的压强公式 3/13 大量分子组成的气体系统的统计假设： Statistical hypothesis of gas system composed of large quantities of molecules (1)分子的速度各不相同，而且通过碰撞不断变化着； The speed of molecules are various, are changing unceasingly through the collision When equilibrium state the distribution of molecules according to the position is even, i.e the molecular number density is everywhere the same, distribution is not affected by gravity dV—体积元(宏观小，微观大) V N V N n = = d d (2)平衡态时分子按位置的分布是均匀的， 即分子数密度到处一样，不受重力影响；
物理学 12-3理想气体的压强公式 第五版 (3)平衡态时分子的速度按方向的分布是各向均匀的 When equilibrium state the distribution of molecular speed according to the direction is even in all directions 7.=0.=0.=0 x N ∑o= 理想气体就是不停地无规则地运动 着的大量无引力的弹性质点的集合 The ideal gas can be viewed as a collection of large quantities of elastic particles carrying constant random motion without gravity 第十二章气体动理论 4/13
第十二章 气体动理论 物理学 第五版 12-3 理想气体的压强公式 4/13 (3)平衡态时分子的速度按方向的分布是各向均匀的。 0 x y z v v v = = = 2 2 2 2 3 x y z = = = v v v v 1 n i ix n n n n i x ix y z i i i n n N = = = = v v v v v 理想气体就是不停地无规则地运动 着的大量无引力的弹性质点的集合 When equilibrium state the distribution of molecular speed according to the direction is even in all directions The ideal gas can be viewed as a collection of large quantities of elastic particles carrying constant random motion without gravity
物理学 12-3理想气体的压强公式 第五版 理想气体压强公式 (Pressure formula of ideal gas) 气体压强本质的定性解释 (The qualitative interpretation of essence of gas pressure 做无规则运动着的大量分子 △F 碰撞器壁时,作用于器壁单位面 雨中雨伞 积上的平均冲力(每单位面积上 Umbrella in rain 单位时间内的平均冲量) When a large quantities of molecules carrying constant random motion collide container walls it effect on the average impulsive force on the wall per unit area(the average impulse at per unit time on the per unit area 第十二章气体动理论 5/13
第十二章 气体动理论 物理学 第五版 12-3 理想气体的压强公式 5/13 气体压强本质的定性解释 (The qualitative interpretation of essence of gas pressure) 做无规则运动着的大量分子 碰撞器壁时，作用于器壁单位面 积上的平均冲力（每单位面积上 单位时间内的平均冲量） F 二 理想气体压强公式 (Pressure formula of ideal gas) When a large quantities of molecules carrying constant random motion collide container walls , it effect on the average impulsive force on the wall per unit area(the average impulse at per unit time on the per unit area) 雨中雨伞 Umbrella in rain