探究"固体的熔化"分组实验的改进

初中物理"热现象"一章,各版本的教材中都安排了一个"探究固体熔化"的分组实验,探究晶体和非晶体的熔化特性,使用的晶体是海波或冰.笔者在教学过程中发现完成该实验的探究过程存在一些问题并做了相应改进.     

晶体溶化实验的改进

利用海波代替萘做晶体熔化实验，避免了禁蒸气对师生健康的影响．由于海波不是常见物质，一般中学制备并不容易．霜是水的晶体，制备比较容易，用它来代替海波做晶体熔化实验效果也很好．实验的方法是：将从冰箱冷冻室得到的软霜约20克迅速加入一预先放有温度计的试管内，调整温度计位置，使玻璃泡处在霜的正中，用手握住试管下部给霜加热．观察到的实验现象是霜的温度达到0℃吸热熔化，熔化过程中吸热（手感到发凉），但温度计示数不变．霜全部熔化后，温度计示数才上升．实验表明，晶体的温度升高到熔点才吸热熔化，整个熔化过程中吸热温…     

海波的熔解和凝固的实验报告

海波的熔解和凝固的实验报告吴菊梅（上海大同中学２０００１１）原来初三物理课本上是用萘做熔解实验的．因为萘有毒，又有刺激性的气味，所以改用海波．实验得出的结果只能验证海波的熔点是４８℃（在误差允许范围内）．而凝固点却得不出是４８℃．本文介绍我们在多次实...     

基于用D I S系统对晶体凝固和熔化的研究

本文采用D I S数字化信息系统对晶体的熔化与凝固实验进行了研究. 在按照初中物理教材的实验安 排, 用海波水浴加热法测量晶体的熔化曲线的基础上, 本文做了两个改进, 一是选择用水替代海波, 先让水凝固成 冰, 然后再利用空气浴法让冰在空气中自然熔化, 从而测量冰的凝固与熔化过程温度 时间曲线( 即凝固曲线和熔 化曲线) , 全程观察冰的凝固与熔化过程其温度及状态的变化; 二是采用D I S温度传感器来替代液体温度计人工测 量温度, 实时记录了冰的凝固曲线和熔化曲线. 实验结果表明, 采取上述改进后, 既提高了该实验的准确性、 可靠性 和直观性, 也增强了实验的说服力     

NB物理实验在初中物理实验教学中的应用——以“探究固体熔化时温度的变化规律”为例

初中物理"探究晶体非晶体熔化实验"这类实验中,由于实验条件苛刻,实验现象不理想,导致真实的实验较难开展.文章以这一实验教学为例,将信息技术融合到日常教学之中,采用NOBOOK物理实验软件的虚拟仿真实验模式,探究海波与石蜡的熔化特性.模拟利用普通温度计与温度传感器测量晶体与非晶体熔化时的温度变化规律.虚拟仿真实验既克服了传统实验的不足,又极大地提高了课堂效率和实验的教学效果,能为线上教学提供较理想的参考方案.     

传感器在固体熔化凝固实验中的运用

基于固体的熔化和凝固实验的传统做法,结合现代测量技术对其进行了改进,对晶体海波和非晶体石蜡的熔化和凝固进行了全程监控,取得了很好的实验效果并节省了实验时间,提高了实验的准确性.     

静电排斥实验失败原因分析与改进

1引言静电排斥实验要想做成功很难,主要有两个原因：一是摩擦起电产生的电荷量不多,带电体间排斥力不强;应把这种弱电场力放大,使实验现象明显,便于观察研究,二是电荷流失速度很大,对实验有影响．本文拟介绍笔者在实验中遇到的问题以及对实验失败原因的分析,并提出了对实验改进的一些看法．     

“萘的熔解实验”成功的关键

“萘的熔解实验”一直作为晶体熔解时温度不变的一个典型例证,而被编入中学物理教材中。此实验都很难做成功。我们对这个实验进行了多次研究与探讨,并取得了很好的效果。现将实验方法介绍给同行,供同志们参考。一、此实验通常的做法及失败的原因通常的做法是将萘粉放入试管中,然后将温度计插入萘粉中,再把试管盛萘粉部位在水浴中加热,并揽拌。     

两个演示实验的改进

导体上电荷分布的实验改进工科中专通用《物理》教材（陕西版）下册Ｐ２７,演示静电平衡导体上的电荷分布实验．由于静电荷的漏失,操作不简捷等原因,使演示难以成功,同时,学生不能亲眼见金属球Ｃ与金属圆筒内壁是否接触,对演示圆筒内壁不带电荷持怀疑态度．笔者在金...     

对电磁打点计时器的改进

J0203型电磁打点计时器是力学实验的重要器材之一．学生分组实验时多次使用它，使用频率较高．学生反复使用打点器时，难免会经常出现机械故障、打点不清、双点、拖尾巴等现象，既耗时间、费纸带，又影响实验效果．笔者在教学中对打点计时器加以改进，收到很好的实验效果．     

关于"太阳在银河系中所受引力与到银心距离r的关系"的讨论

讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系，指出引力场强g并不是与r的平方成反比，这是由于银河系的大小和形状不能忽略造成的．强调了万有引力定律的适用条件．     

On the predictability of the positions of the convergence zones in the ocean

The disagreement between the experimental and calculated positions of the first convergence zone are known from many publications. The most probable cause for such a disagreement, namely, the incorrect specification of the input data for the calculations, is considered. The lack of simultaneity between the hydrological surveys of the region and the acoustic experiments is emphasized. The experimental data obtained by the author in five ocean regions are presented. These data characterize the diurnal variability of the distance from the source to the nearest boundary of the convergence zone. The relations proposed by different researchers for calculating the sound speed from the temperature, salinity, and hydrostatic pressure are analyzed. It is shown that these relations lead to a substantial difference in the estimated depth dependence of the hydrostatic gradient of the sound speed. The position of the first convergence zone is calculated for the propagation conditions determined by vertical temperature and salinity profiles with the subsequent recalculation of these profiles into sound speed profiles by using eight different formulas known from the literature. It is shown that different formulas lead to different values of the distance to the first zone; this difference is substantially greater than that between the calculations and experiment. The necessity of improving the recalculation relations in view of the experimental data on sound propagation in natural oceanic waveguides, including the data on the actual positions of the convergence zones, is emphasized.     

On the calculation of the bremsstrahlung in the region of the plasma frequency

On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

Extracting the wavefunction of the LSP at the LHC

We consider associated production of squarks and gluinos with the lightest supersymmetric particle (LSP), or states nearly degenerate in mass with it. Though sub-dominant to pair production of color SU(3)-charged superpartners, these processes are directly sensitive to the wavefunction composition of the lightest neutralinos. Exploiting event-shape variables - including some introduced here for the first time - we are able to identify the composition of the LSP by selecting events involving a single high-pT jet recoiling against missing transverse energy. We illustrate the proposed technique on a set of benchmark cases and propose methods for applying these results in more realistic experimental environments.     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

On the Question of the Source of the Apokamp

Technical Physics - The object of this work is the apokamp—a new type of plasma jet, which is formed from a bright offshoot emerging at the bending point of a channel of a high-voltage...