Journal of Crystal Growth 310(2008)2668–2672
Pattern formation of crystals in storm glass
Yasuko Tanaka,Koichi Hagano,Tomoyasu Kuno,Kazushige Nagashima Ã
Department of Physics,Meiji University,1-1-1Higashimita,Tama-ku,Kawasaki 214-8571,Japan
Received 16January 2008;accepted 17January 2008
Communicated by T.F.Kuech Available online 1February 2008
Abstract
‘‘Storm glass’’is a aled glass tube containing a camphor–ethanol solution with aqueous NH 4Cl and KNO 3solution.In 19th century England,the pattern and quantity of the crystals formed were obrved and interpreted as a weather forecasting tool.In the prent study,the pattern formation of t
he crystals in the storm glass solution was investigated by focusing on one parameter,such as the applied temperature.The growth patterns of the crystals in the storm glass solution were controlled using a directional growth apparatus and obrved in situ as a function of the growth rate.Crystals grown in camphor ethanol solution were also obrved for comparison.In addition,a replica of the storm glass attached to a temperature control system was constructed in order to examine the effect of the history of temperature variations on the crystals.X-ray diffraction patterns of the crystals were obtained to clarify the species of the crystals in the storm glass.
r 2008Elvier B.V.All rights rerved.
PACS:47.20.Hw;81.30.Fb
Keywords:A1.Crystal morphology;A1.Directional solidification;A1.X-ray diffraction;A2.Growth from solutions;B1.Camphor
1.Introduction
‘‘Storm glass’’(also referred to as storm bottle or camphor glass)consists of a aled glass tube containing a solution of camphor (C 10H 16O)dissolved in ethanol,water,NH 4Cl and KNO 3[1].It was
empirically ud as a weather forecasting tool,mainly in 19th century England.The pattern and quantity of the crystals changed depend-ing on the weather conditions.The following pre-dictions about the weather were made depending on the appearance of crystals;the growth dendrites filling the glass tube suggested cold and stormy weather,melting crystals suggested warm weather,few crystals in a clear solution suggested fine and dry weather,floating star-like crystals suggested cold weather,and floating feather-like crystals suggested rain.
Nakamoto and Hiroi [2]examined the effect of a number of parameters applied to the storm glass from the outside on the pattern and quantity of the crystals.The change in
the appearance of crystals was not caud by a change in atmospheric pressure,humidity,electric field,or magnetic field,but solely by a change in temperature.It was difficult to find a correlation between the variations in the crystal-lization and the changes in the weather uful in forecasting the weather.
On the other hand,pattern formation of growing crystals has been paid much attention [3,4].In this n,the crystallization in the storm glass showing a variety of patterns is an amusing problem and also scientifically interesting.The objective of the prent study is to characterize the growth patterns
in the storm glass solution using a directional growth apparatus,which will facilitate control of the growth rate of crystals and to discuss the correlation between the growth conditions and the crystal patterns [5,6].The species of the crystals formed in the storm glass solution were examined ex situ by X-ray diffraction (XRD).A replica of the storm glass connected to a temperature control system was con-structed in order to examine the effect of the history of temperature variation applied on the crystals in the storm glass.
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0022-0248/$-e front matter r 2008Elvier B.V.All rights rerved.doi:10.1016/j.jcrysgro.2008.01.037
ÃCorresponding author.Tel./fax:+81449347269.
E-mail address:iji.ac.jp (K.Nagashima).
2.Experimental procedure
The sample solution ud was the same as that ud in the storm glass.Two solutions were prepared according to the Ref.[2].Thefirst solution was prepared by mixing d-camphor(30g)and etha
nol(100ml).A cond solution was prepared by mixing NH4Cl(7.5g),KNO3(7.5g),and ultrapure water.The ultrapure water was ud to adjust the total volume of the solution to100ml.Finally,the storm glass solution was made by mixing the two solutions at the same volume ratio.Although no crystals were obrved in either solution alone,the crystals nucleated and precipi-tated when the solutions were mixed.When the storm glass solution was injected into the growth cell,the crystals in the solution were dissolved at401C to ensure uniform composition of the solution.
In the prent study,three types of experiments were carried out.The experimental procedures were as follows: (i)The directional growth apparatus consisted of two
pavarotticopper blocks horizontally arranged with a5mm gap [5,6].The growth cell(20Â20Â0.3mm)consisted of two optical glass placed on blocks at29and31C.As
a result,a temperature gradient was applied in the
growth cell.Crystals appeared in the colder region of the growth cell.When the growth cell was moved toward the colder block at a constant velocity V,the growth interface was located at almost the same position between the two blocks.As a result,the crystals were grown at V and were obrved in situ using an optical microscope.The growth of camphor crystals in camphor–ethanol sol
ution(65%in weight) was also obrved under the same growth conditions in order to clarify the effect of the minor components (NH4Cl and KNO3)and water in the storm glass solution.
(ii)XRD patterns of the crystals were obrved ex situ.
平安夜的英文The crystals and the solution were parated by filtration.The crystals were rind with a water–ethanol solution in order to remove impurities in the solution trapped between crystals.The powdered sample crystals were placed on the quartz glass and were dried.Diffraction patterns were obtained using a XRD system(CN4036A1Rigaku,Japan).
(iii)A replica of the storm glass was constructed using a aled glass tube(30mm in diameter)containing about 100ml of storm glass solution.The glass tube was immerd in a coolant in a heat sink consisting of a double-walled glass window for in situ obrvation.
The temperature of the storm glass was controlled by circulating the coolant using a temperature control system.The cooling process cooled from30to201C and the heating process heated from10to201C at a constant rate of11C/h.The process were obrved in situ.Thefinal temperatures in each ca were the same in order to determine the effect of the initial conditions on thefinal crystals.In addition,periodic
temperature variations were applied.The maximum and minimum temperatures were30and201C, respectively.The periods of the temperature variations were10h(short period)and20h(long period).In each ca,two runs,with initial temperatures of20and 301C,were carried out for comparison.
3.Results and discussion
3.1.Directional growth
Fig.1shows images of crystals growing in the storm glass solution(Fig.1(a)–(d)),and in the camphor–ethanol solution(Fig.1(e)),using the directional growth apparatus as a function of the movement velocity V of the growth cell.The values of V are(a)0,(b)0.4,(c)5,(d)10,and(e) 10m m sÀ1.The thin growth cell was aligned horizontally; therefore,there was no gravitational effect.The upper region of the image is the hot region,while the lower region is the cold region.
When the growth cell was maintained in a stationary condition at V¼0,the crystals were annealed and became
Fig.1.Images of crystals growing in storm glass solution by using the directional growth apparatus as a function of the movement velocity V of the growth cell.Fig.1(e)shows the image of camphor crystals growing in camphor–ethanol solution for comparison.The values of V are(a)0,(b) 0.4,(c)5,(d)10,and(e)10m m sÀ1(camphor–ethanol).
Y.Tanaka et al./Journal of Crystal Growth310(2008)2668–26722669
round(Fig.1(a)).At V¼0.4m m sÀ1(Fig.1(b)),the crystals grew with broad main branches and a few side branches. At V¼5m m sÀ1(Fig.1(c)),the crystals grew withfine side branches(dendritic pattern).At V¼10m m sÀ1(Fig.1(d)), successive nucleation occurred in front of the bulk crystals. The nucleated crystals developed main branches withfine side branches(star-like pattern).Upon changing the movement velocity of the growth cell(the cooling rate), typical crystal patterns obrved in the storm glass were obtained.The prent results also indicated that the major factor controlling the growth pattern was the temperature. The growth of camphor crystals in the camphor–ethanol solution also obrved using the same apparatus and the same growth conditions for comparison.Fig.1(e)shows the results of the camphor growing at V¼10m m sÀ1.In this ca,no nucleation occurred,in contrast to the results obtained for the storm glass solution shown in Fig.1(d). Thus,the minor components(ammonium chloride and potassium nitrate)and water in the storm glass
solution were determined to induce successive nucleation at higher growth rates(Fig.1(d)).The inhibition of nucleation at lower growth rates(Fig.1(b)and(c))may be attributed to the diffusion length.The diffusion length of a solute in a solution is proportional to D/V.Where D is the diffusion coefficient of the solute in the solution.Therefore,when V is small,the diffusion length is long,which suggests that the camphor poor region in front of the growing bulk crystals is long.Conquently,nucleation was inhibited by lowering the camphor concentration at lower V values.
3.2.XRD patterns of the crystals
Fig.2shows the XRD patterns of crystals of KNO3, NH4Cl,camphor,and the crystals grown in the storm glass solution.The diffraction pattern of the crystals in the storm glass solution,which showed three large peaks around151 and a small peak at211,corresponded to the peaks of camphor(note that a small peak at191corresponding to KNO3might be contamination originated from the solution trapped between camphor crystals).Mjojo[7] demonstrated that there are three phas of crystal structures of camphor,and that hexagonal crystals(pha II)form at room temperature.The growth patterns obrved in the prent study also showed hexagonal dendrites as shown in Fig.1(c)and(d).
Therefore,one of effects of minor components(KNO3 and NH4Cl)and water in the storm glass solution is the nucleation of camphor crystals at higher values of V.In order to clarify the effect of the components on the nucleation in detail,the nucleation temperatures must be obtained as a function of concentrations of KNO3,NH4Cl, and water.Details to this end are currently underway.
3.3.Replica of storm glass
Fig.3shows the quential images of the crystals in the replica of the storm glass.Fig.3(a)–(d)shows the cooling process,and Fig.3(a0)–(d0)show the heating process.After the initial temperature,images were taken at(a)and(a0) 0h,(b)and(b0)3h,(c)and(c0)10h,and(d)and(d0)34h. During the cooling process,the temperature changed from 30to201C,and during the heating process the temperature changed from10to201C.Thefinal temperature was the same in each ca.After the temperature reached201C (Fig.3(c)and(c0)),the temperature was maintained at 201C for24h(Fig.3(d)and(d0)).
condition
During the cooling process(Fig.3(a)–(c)),the crystals grew rapidly;the glass tube was almostfilled with the crystals.While the glass tube was maintained at201C for 24h(Fig.3(d)),the height of crystals gradually decread due to an annealing effect in the gravity,and a clear solution appeared at the top of the glass cell.During heating process(Fig.3(a0)–(c0)),the crystals slowly melted. Even24h after maintaining the temperature at201C (Fig.3(d0)),the amount of crystals did not change.
Fig.2.X-ray diffraction patterns of KNO3,NH4Cl,camphor,and the crystals grown in the storm glass
solution.Fig.3.Sequential images of crystals in the replica of the storm glass: (a)–(d)show the cooling process and(a0)–(d0)show the heating process.
Y.Tanaka et al./Journal of Crystal Growth310(2008)2668–2672 2670
Although thefinal temperature was the same for both the ca of cooling and heating,the appearance of the crystals was completely different.This obrvation suggests that the storm glass does not act as a thermometer,but rather an apparatus affected by the history of the temperature variation.The following paragraph will discuss the amount of time that the crystals in the storm glass are affected by the history of the temperature variation.
Fig.4shows the time variation of the height ratio of the crystals to the solution when periodic temperature varia-tions are applied.A height ratio¼0indicates no crystals and a height ratio¼1indicates the crystals completelyfill the storm glass.The temperature was changed between20 and301C periodically.The periods of the temperature variations were:(a)10h(short)and(b)20h(long).In each ca,two experimental runs were carried out.One started with no crystals at301C and the other started with crystals of height(¼0.7–0.8)at201C.The only difference between the two was the pha of the temperature variation,which differed by half of the period.The images on the left hand side of thefigure show the initial appearance of the storm glass.adventure是什么意思
After periodic temperature variation was applied to the sample,the crystals began to grow and melt.As a result, the curves of the height ratio oscillated,showing local maxima and minima in the period of the temperature variation applied.The gradual decrea in the curves may be attributed to an annealing effect due to gravity.
ofcour
In the ca of the short period applied(Fig.4(a)),the local maxima(or local minima)of the height ratio in the two curves for different initial conditions rapidly approached almost the same value.In other words,the two oscillating curves overlapped despite the difference in the initial conditions after about one period(10h)as indicated by the arrow in Fig.4(a).
However,in the ca of the long applied period (Fig.4(b)),two curves are shown for different initial conditions that deviated during the initial stage.Finally, after aboutfive periods(100h),as indicated by the arrow in Fig.4(b),two curves overlapped and showed almost the same oscillation behavior around the height ratio0.4–0.5. Therefore,the difference in the initial conditions affected the amount of the crystals for a much longer period when the period of the temperature variation was applied for a longer amount of time.The daily variation of temperature (24h)almost agrees with the long period,therefore,the crystals in the storm glass are thought to be affected by the history of temperature variation over veral days. Finally,it should be noted that in order to clarify the mechani
sm by which numerous appearances of crystals form depending on the daily variations of temperature,the diffusion process of camphor,potassium nitrate,and ammonium chloride caud by crystal growth and melting in water–ethanol solution,and the interactions between molecules must be examined.Furthermore,the storm glass is vertically arranged;therefore,the effect of gravity on the convection in the solution is also important.Detailed investigations of this nature are currently underway.
4.Conclusions
(i)Typical crystal patterns that appear in storm glass
were obtained during the directional growth by controlling the growth rates(cooling rate).In addition, minor components(potassium nitrate and ammonium chloride)and water in the solution controlled the nucleation of the camphor crystals at higher values of the growth rates.
(ii)XRD showed that the crystals in the storm glass were camphor.
(iii)The history of the periodic temperature variation affected the pattern and the quantity of the crystals.In ca of the daily variations in temperature,the appearance of the crystals was affected by the temperature history over veral days.
Fig.4.Time variation of the height ratio of crystals to solution,when
californiadreaming>hold
periodic temperature variations were applied.The periods of themrmr
s开头的英文单词
temperature variations were:(a)10h(short)and(b)20h(long).The
images on the left hand side of thefigure show the initial appearance of the
storm glass.
Y.Tanaka et al./Journal of Crystal Growth310(2008)2668–26722671
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Y.Tanaka et al./Journal of Crystal Growth310(2008)2668–2672 2672
