Science Behind the Galileo Thermometer Essay

Science Behind the Galileo Thermometer Essay.

The Galileo thermometer, used to measure temperature, is mainly used for home décor nowadays. The stylish thermometer used in people’s homes today is based off of a thermo scope Galileo invented in the early 1600’s. Although not exact, the Galileo thermometer is moderately accurate. The thermometer has several glass blown bubbles, with a colored liquid inside which is just for decoration. The bubbles have metal tags attached to the bottom of them with an engraved number on it, for example seventy, for seventy degrees Fahrenheit.

The glass bubbles float in a water filled glass tube, which may vary in size. The glass bubble floating, usually on its own in the middle of the tube, is what the temperature is approximately, but how exactly does floating glass measure temperature?

The glass bubbles in the Galileo thermometer are adjusted to specific densities by the differing amounts of liquid and even the type of liquid within the glass. The different densities will be affected by the waters density, which changes as it expands or contracts with temperature difference.

As the temperature within the room heats up, so does the temperature of the water within the vertical glass tube. Once the water within the thermometer is room temperature, the glass bubbles densities will either be more or less dense than the water. Depending on the temperature, the glass bubbles will either sink or float. The one glass bubble that is either in the middle of the tube, floating near the top but sinking slightly, or sinking near the bottom but floating slightly, is the temperature of the room.

For example, if it is seventy degrees Fahrenheit in the room, the glass bubbles labeled sixty and sixty-five, having the highest densities, will sink, while the glass bubbles labeled seventy-five and eighty, having the lowest densities, will float, seventy will be somewhere in between. Obviously there are temperatures other than those five, which is why the Galileo thermometer is not the most accurate reading of temperature. The Galileo thermometer is used for decoration because if someone wanted a real reading of temperature, they would most likely not go to a thermometer where the reading would be seventy-ish degrees Fahrenheit.

Although the Galileo thermometer is named after Galileo, the thermometer he invented, properly called a thermo scope, did not have the same properties as the actual Galileo thermometer. I believe the reason it is named after Galileo is because he did, with his invention of the thermo scope, figure out that with a temperature change the water’s density will change too. This is the reason behind why today’s Galileo thermometer works the way it does.

In conclusion, the Galileo thermometer, named after Galileo’s discovery of water’s density changing with temperature, measures temperature with glass bubbles varied in densities. Although functional, the Galileo thermometer is not the most accurate reading of temperature today due to the lack of specific temperature increments. With its sleek design, it is pleasing to the eye, which is why in most cases people today have these in their homes or offices.

Works Cited

Heckert, Paul A. “Galileo’s Thermometer” Suite 101. 7 Mar. 2007. 5 Mar. 2009 .

“How Does a Galileo Thermometer Work” How Stuff Works. HowStuffWorks inc. 5 Mar. 2009 .

Przewoznik, James. “Galileo Thermometer Operation” Ask A Scientist. 7 Feb. 2005. 5 Mar. 2009 .

Science Behind the Galileo Thermometer Essay

Heat of Decomposition of Hydrogen Peroxide Essay

Heat of Decomposition of Hydrogen Peroxide Essay.


Our main purpose is to familiarise ourselves with a method to find the heat of decomposition of a compound (hydrogen peroxide). Firstly, we will be looking at information about calorimeter and what it meant by heat of decomposition. Also, we will try to understand why we have to subtract the heat absorbed by the calorimeter to find the heat of decomposition of hydrogen peroxide. Therefore, we found the heat capacity of calorimeter. After that, the enthalpy of decomposition of hydrogen peroxide was calculated by finding the amount of heat lost by solution and the heat absorbed by the calorimeter.

Then, the heat absorbed by the calorimeter was subtracted from the heat lost by the solution to determine the amount of heat absorbed by hydrogen peroxide. The enthalpy of decomposition of hydrogen peroxide obtained is -57.9kJ/mol. Finally, we would look at how the results differ from the literature value and understand reasons to why the difference in the values occurs and find methods to prevent this.


* Calorimeter

1A calorimeter is a device that helps to measure the heat of reaction. There are two types of calorimeters which are usually used. The sophisticated and expensive one, while the other can be easily made and available cheap. The one used for this experiment is the simple and cheap one which is basically a Styrofoam cup because its container walls are well insulated to prevent or reduce the heat change to environment.

2However, the calorimeter would also absorb heat as it is a simple calorimeter and thus it is a necessity to take it into the consideration while doing the calculations to find the heat of decomposition of hydrogen peroxide. Also, the reactants are inside the calorimeter with a lid on top before the reaction has been initiated to prevent heat from escaping or it would cause the results to turn inaccurate. Besides this, a thermometer will be placed inside to constantly monitor the temperature as time progresses. It assists in finding the temperature difference before and after the reaction has completed.

* Heat of decomposition

Heat of decomposition is defined as the breaking down of a single compound (Hydrogen peroxide) into 2 simpler compounds or elements upon the application of heat. Enthalpy of decomposition is thus defined as the amount of heat required to chemically break down a compound. In this experiment we will be trying to find the heat of decomposition of hydrogen peroxide. 4Hydrogen peroxide is an unstable compound. Under normal room conditions, it would break down to water and oxygen. However, the process is very slow to be completed in a normal laboratory period. As a solution, catalyst [Iron (III) nitrate] was introduced. It helps to speed up the process without being consumed itself.


There are basically 2 parts to this experiment, thus 2 procedures.

* Heat capacity of calorimeter (Part 1)

A simple calorimeter was firstly made using a thermometer, Styrofoam cup and cover. 30ml of tap water next was poured into the simple calorimeter cup and covered back with the cover and the thermometer. It was left at the room temperature for about 5-10 minutes before recording the temperature to the nearest 0.5oC.

Another 30ml of water was poured into a 250ml beaker and heated using a hot plate until the temperature was about 20oC more than the room temperature which would means about 44-50 oC. Then, the heated water was allowed to stand for 1 minute and its temperature was recorded immediately to the nearest 0.5oC and poured completely into the calorimeter. The cover was covered over it with the thermometer along. The cup was next swirled once. The temperature was observed for 3 minutes and was recorded every 15 seconds.

* Enthalpy of decomposition of hydrogen peroxide solution (Part 2) After the first part of the experiment was completed, the calorimeter and the thermometer were dried completely. 50ml of 1.0M hydrogen peroxide (H2O2) was then cautiously measured and poured into the calorimeter. The cover was then replaced along with the thermometer. The solution was swirled once and temperature was recorded every single minute for 4 minutes. At the 5-minute mark, the cover and the thermometer were removed. 10ml of 0.50M Iron (III) nitrate [Fe(NO3)3] was measured and added into the calorimeter containing the hydrogen peroxide.

Temperature was next measured at 5.5 minute mark and for every succeeding minute till a total of 20 minutes. A temperature vs. time curve was then constructed with the data obtained from the experiment to determine change in temperature. Next, enthalpy of the decomposition of hydrogen peroxide was calculated. A starting temperature can be found by extrapolating the 5 points prior to adding the catalyst to the point of mixing. The final temperature can also be found by extrapolating the linear portion of the graph to the point of mixing.

* Discussion

As the literature value stated in the data sheet, the heat of decomposition of the hydrogen peroxide is -94.6kJ/mol. However the value obtained was only -57.9kJ/mol. This was because the heat has been lost to the surroundings around outside the calorimeter. The calorimeter is not perfect and simple and thus its cover is not proper and does not fully cover the top of the Styrofoam cup, leaving a small opening. The heat could have escaped from the calorimeter through here. Besides this, the experiment was done for a long period of 20 minutes. The longer the period, there is more time for the heat to escape from the imperfect calorimeter. This leads to a lower temperature than expected to be recorded as time progresses. This leads to lower temperature difference leading to a lower heat of decomposition of hydrogen peroxide to be obtained from the reaction.

Another possibility of losing heat occurred during the addition of the Iron (III) nitrate as catalyst inside. Once it was added, the reaction was increased rapidly producing a lot of heat. However, the lid was not covered on time and was slow which led to a significant amount of heat to be lost to the surroundings. Also, the temperature shown was not accurate due to the poor calibration of the thermometer. Often estimation to the nearest 0.1oC has to be done when recording the results. Due to the usage of an imperfect calorimeter, the results obtained were inaccurate. Thus we can improve this experiment by using a perfect calorimeter which will help to reduce heat from escaping from the calorimeter drastically and also reduce the heat from being absorbed by the calorimeter itself. 3One perfect example would be the usage of the adiabatic calorimeter.

The calorimeter’s vessel is basically surrounded by a jacket containing water. Therefore, the temperature of which will automatically be same as the temperature inside the vessel. Since the temperature of the reacting system and the surroundings is the same, there is no heat passed in either direction. This would lead to much more accurate results. Besides this, we can also try to reduce the time taken to 15 minutes. I would recommend this because the longer the time taken for the experiment, the higher the possibilities for the calorimeter to lose heat to the surroundings. Hence, by reducing the time, the possibilities of losing heat is minimised. Apart from this, we can also use a thermometer with a finer calibration to note the slightest difference in the temperature which could lead to the significant changes in the results obtained.


From the results obtained, I can conclude that the usage of the simple calorimeter is not an ideal choice due to possibilities of losing heat to the surroundings. A sophisticated and better calorimeter has to be used. 5Styrofoam cup calorimeter isn’t recommended for this decomposition reaction as it involves production of a gas, Oxygen which can escape from the cup easily.

Besides this, we were better familiarised with a method to find the heat of decomposition of compounds with the use of calorimeter. It can also be concluded that hydrogen peroxide is not a stable compound and breaks down slowly in room temperature and pressure and can be speed up by the usage of catalyst. In overall, the values obtained from the experiment are not useful because of the severe errors which occurred during the experiment mainly due to the apparatus used.

1CaCT, Calorimetry: Measuring heats of reaction. [Accessed 19 July 2012] 2Solomon, S., Rutkowsky, S and Boritz, C (2009) Everyday investigations for General Chemistry John Wiley & Sons 4Cool sciences. Heat of decomposition of hydrogen peroxide. [Accessed 22 July 2012] 5About Chemistry. Measurement of Heat flow and Enthalpy Change; Calorimetry – Coffee Cup Calorimetry and Bomb Calorimetry. [Accessed 25 July 2012] 3Silcocks, C.G. Physical Chemistry: Thermochemistry and thermodynamics,3rd Ed,: Macdonald & Evans Ltd, 1982.

Heat of Decomposition of Hydrogen Peroxide Essay

A Misty Morning Essay

A Misty Morning Essay.

It was one of the last days of December when I experienced a misty morning. Mist in Yangon is pretty uncommon to be seen as we have tropical weather.However, on that particular day, the whole atmosphere was covered with mist. And it lasted for a few hours in the morning. The coldness and the freshness of the atmosphere gave the energy to start a new day.It feels like living in a mountain city like May Myo.On that day, I rose earlier than usual with the freezing wind that blew into my room.

Looking out of the window, the chill and the fresh smell of the winter morning welcomed me gladly.At first I was quite amazed to notice the mist.Because it was pretty long enough that we encountered haze in our city.The chirping sounds of the birds from the distance trees and the cold breeze energized me to go for a jog.I woke up my parents and all of us were excited to go out and enjoy the great weather.

We set off for Inya Lake which is within the walking distance from my home.

My parents are fond of walking along the path on the bank of the lake.The air blowing through the surface of the water is refreshing and they do enjoyed it.As soon as I stepped out of the house, the coldness and the freezing wind made me shivered.Though I wrapped up myself in many layers, I felt the intense cold through my bones.At the time we arrived the lake, the sky was still unclear and the sun was hidden in the mist.The surrounding was still hazy and rather on the dark side.But it had already passed the usual time of sun rise.Everything was unclear and obsure with mist that we couldn’t even see a few distance.The coldness made my breath visible.It is a very enjoyable thing to play around when I was a little kid.

Ther were not so many people on the walking path.Supposingly because of the mist and cold weather.The old people who were usually walking or doing exercises couldn’t be found. We saw only a few athletic young people on some training.We ran for about half and hour to warm up ourselves.But it didn’t help very much because the weather is still cold and chilling.All of sudden, the sun came out of the mist and the fog started to disappear.The forst that had been covering the grass started to melt down.The temperature began to warm and we felt more comfortable than before.After having a few exercises, we went for our breakfast at a food stall which is not so far from there.It offered Shan tradtional snacks and breakfast menu.

A Misty Morning Essay

Weather and Mood Essay

Weather and Mood Essay.

The weather controls every aspect of our daily lives. It influences our choices and decisions on what to wear, what to eat, and what kind of activities we should do. Ancient civilizations feared and respected the power of the weather. They created and worshiped different weather gods. During extreme weather conditions such as during dry seasons and floods, they used human sacrifices to appeal to the god of sun or to the god of the rain. Survival and biological necessity defined the relationship between men and the weather.

Even with the advance of science and philosophy in the next civilizations, the study of weather was primary linked to a physiological and biological needs. Research studies with psychological approach were rare and often ignored because scientists and researchers did not believe in weather’s psychological effects on humans. According to the French philosopher Blaise Pascal, who strongly denied any correlation between weather and mood, ” the weather and my mood have little connection.

I have my foggy and my fine days within me; my prosperity and my misfortune has nothing to do with the matter” ( n d).

Thanks to the psychological revolution in 1950’s, more research studies have dedicated a lot of thought to this relationship between weather and mood. As a result of a special interest in this correlation between weather and mood, much research has been performed to demonstrate that weather has influence over people’s emotion and behavior. Keller et al.(2005) investigated the effect of temperature, pressure, and the time spent outside on the psychological processes.( Keller et al., 2005).

Their research study demonstrated that sunny weather with high temperature and high pressure has a positive effect on the mood of participants who spent more than 30 minutes outside, but among participants who spent less than 30 minutes, higher temperature and pressure were associated with lower mood.( Keller et al., 2005). In a similar multidimensional experimental study, Howarth and Hoffman (1984) studied the impact of different weather variables such as humidity, temperature, and hours of sunshine on mood ( Howarth & Hoffman, 1984). They concluded that sunshine is associated with the mood of optimism, where as humidity and and low temperature were associated with the mood of anxiety, aggression, Depression, and low concentration (Howarth & Hoffman,1984).

while these research findings showed significant correlation between mood and several weather variables and both demonstrated the effect of a specific or limited range of temperatures on mood, they did not clearly examined the effect of extreme temperatures . Both research were run during a short period of time and at the same place, which made it impossible to test the mood of their participants when the temperature is below zero or higher than 100 degrees Fahrenheit. Monitoring the mood of participants only during the month of November when the temperature can only vary between 10 and 60 degrees Fahrenheit, Howarth and Hoffman(1984), for example, could not demonstrate the effect of extreme temperatures on the mood of their participants.

In this study, we decided to broaden “our experimental laboratory” to include different states in the country with completely different climatic characteristics. Our research, which was a combination of correlation research and experimental study, was run in Alaska which is known for its bitter and cold weather, Arizona which is known for its heat waves that can reach 110 degrees Fahrenheit, and Florida which has a very pleasant weather with optimum temperature. Participants from Alaska and Arizona set up our experimental group, whereas participants from Florida set up our control group. We hypothesized that mood ( our independent variable) would dramatically decline as temperature (our dependent variable) drops below zero degree Fahrenheit ( positive correlation) or rises above 110 degree Fahrenheit ( negative correlation ) and would be boosted at an optimum temperature ( between 70 and 80 degrees Fahrenheit).



300 people were randomly selected to participate in the experiment ( 160 males and 140 females). They ranged in age from 18 to 35. subjects had no previous psychiatric disorder nor any serious health problems. We assigned 100 participants for each states ( Alaska, Florida, and Arizona). To ensure consistency, participants from each state were selected from the same demographic area with the same median household income ($45,000 was the average median household income) and with the same racial and ethnic characteristics (the majority was white Americans). Volunteers were not compensated for their participation in the research.


To collect our data, We set up surveys that rely only on emails. Participants answered questions related to their well- being, and state of mood. Each participant got a score that evaluated him/her as a low or high mood person. In our experimental group, subjects from Alaska took the survey during winter time when the temperature was between – 40 and – 60 degrees Fahrenheits and again in summer when the temperature was in the 70’s. Similarly, subject from Arizona were tested under extremely hot climate as well as during pleasant climate. In our control group, volunteers from Florida were also tested twice but during the same pleasant days when the optimum temperature was between 70 and 80 degrees Fahrenheit. We obtained data on temperature in the three different states from

The survey consisted of 5 simple questions that participants were requested to answer honestly without knowing the involvement of weather. Subjects were asked to report what they had felt during the last seven days. The basic mood assessment that was asked to be completed by the participants was the following model :

-Rate your level of happiness on a scale of 1 to 10

-Rate your level of stress on a scale of 1 to 10

-Rate your optimism about your future on a scale of 1 to 10

-Rate your suicidal thought on a scale of 1 to 10

-Rate you sleeping patterns on a scale of 1 to 10


In the first experiment, participants in the experimental group (from Arizona and Alaska) scored very low (1 out of 5) in the mood assessment when they were exposed to very low and high temperature. On the other hand, they scored very high (5 out of 5 ) when they were exposed to an average optimum temperature of 74 degrees Fahrenheit. As expected, participants in the control group (Florida) scored the highest in both mood assessments (5 out of 5) because they were exposed to a pleasant climate with an optimal temperature.


The results supported the hypothesis that very hot climate as well as extremely cold weather affect negatively our mood. Nice weather with an optimum temperature of 70 to 80 degrees Fahrenheit boosts our moral, makes us happy, and improves vitality.

The results not only do support the findings of previous studies, but also give us a better appreciation of one of the most effecting weather variables: the temperature. Keller et al.’s prediction and exclusive findings about the effect of weather on mood and cognition focused on the relationship between atmospheric pressure and temperature and cognition and memory ( Keller et al., 2005). Despite the fact that Howarth and Hoffman (1984) ran a multidimensional study in which several weather variables were included (such as precipitation, wind, humidity, temperature, barometric
pressure, and hours of sunshine), their findings demonstrated that temperature had the greatest effect on mood (Howarth & Hoffman, 1984).

Many limitations affected the outcome and the success of the research. Relying on random sampling and on the survey data to run our experiment did not allow us to look at the cases in more depth. Moreover, the wording used in the survey questions might have affected the survey results because the phrasing of some of the questions might have been interpreted differently among participants and subsequently affecting the way how they would report their behavior. The accuracy of the data depended tremendously on the honesty of the participants, a factor that we cannot verify or control. Horn-thorn effect could have affected the accuracy of our data as participants could alter their behavior or state of mood, simply because they were being studied.

Participants could have lied about their true emotions or mood. In addition, we couldn’t control the other confounding variables that might influence the independent variable ( mood) or the dependent variable ( temperature). It was very hard to eliminate other factors that might have affected the mood of the participants such as their psychological and social problems and it was hard to distinguish between positive mood or happiness and life satisfaction as a whole. Isolating temperature from other weather variables was also a big challenge. The interference of other weather factors such as clouds, wind, or barometric pressure could have affected the mood of the participants.

As we were running this experimental research, we adhered to the APA ethic codes and we respected all the ethical principles developed by APA and other international psychological organizations. Before taking the survey, we obtained participants’ informed consent and we made it clear that their information would stay confidential. No harm or discomfort was caused to the participants during or after the experiment. At the end of the experiment, participants were fully debriefed ( temperature and weather were not mentioned until debriefing to guarantee the success of the study).

The purpose of this research is to enrich previous studies on the effect of different weather variables on mood and cognition. Knowing that mood peaks at optimum temperature ( 70 to 80 degrees Fahrenheit) and declines with higher and lower temperature can primarily help psychologists to evaluate people who suffer from depression from a new perspectives.

A new “weather therapy” can be useful in treating people with psychiatric disorder such as depression and post-traumatic diseases. This study can also advance the field of industrial psychology by understanding the effect of high and low temperature on employees and productivity. Retail industry, as well, can benefit from the findings of this study. Predicting and understanding the behavior of their customers based on weather-mood correlation, retailers can adjust their sales analysis data to maximize profit or minimize losses.


Howarth, E. E., & Hoffman, M. S. (1984). A multidimensional approach to the relationship between mood and weather. _British Journal Of Psychology_, _75_(1), 15.

Keller, M. C., Fredrickson, B. L., Ybarra, O., Côt, S., Johnson, K., Mikels, J., & … Wager, T. (2005). A warm heart and a clear head. _Psychological Science (Wiley-Blackwell)_, _16_(9), 724-731.

Pascal, Blaise. _Thoughts,_ translated by W. F. Trotter. Vol. XLVIII, Part 1. The Harvard Classics. NewYork: P.F. Collier & Son, 1909-14;, 2001.

Weather and Mood Essay

A World Without Friction Essay

A World Without Friction Essay.

A World Without Friction Essay. Although friction may seem like a minor issue, its absence would chance life as we know it. There would be many negative effects of this like not being able to gain traction on any surface and your ipods earplugs always falling out. Also, there would be many positive effects, such as eliminating the need for coolant in engines and lubricant in machines. Moreover, the absence of friction would be both bad and good.

Without friction, many obvious things which we take for granted would not function the way we like.

Shoelaces would untie themselves, zippers would always unzip (unless they were upside-down), nails, screws, nuts and bolts would work themselves loose, and driving as we know it would be impossible. Objects would be unable to gain traction on any surface. Therefore, the only way to move without friction would be through force of reaction. One would need to push something to get motion in opposite direction. Then even to stop, one would need to collide with something.

In short, one would need some mechanism like rockets have to control motion. A larger problem would be that the threat of meteorites would be multiplied immensely (Goulding). Since there would be no resistance as the meteorite entered Earths atmosphere, even small meteorites would be able to penetrate our atmosphere and cause immense damage (Goulding). The damage a large meteor would cause would be catastrophic.

Several ramifications that probably dont come readily to mind are the effects on the human body, thermodynamics and plate tectonics. Without friction, many functions of the human body would not work. Procreation would be impossible as friction is necessary for the male orgasm. Digestion would be impossible as the human body uses friction to digest and move food throughout the body. Under conditions where the coefficient of friction is 0 on all surfaces, the laws of Thermodynamics would be useless (Goulding).

Since friction creates heat, without friction there would be no heat, therefore, no laws of Thermodynamics (Goulding). Plate tectonics would also be drastically altered in the absence of friction. Currently the plates that make up the surface of the earth are sliding over each other at an incredibly slow rate. Without friction, the movements of these plates would rapidly accelerate. Continental drift would be accelerated and continents would collide and this would lead to disaster.

Not all of the changes brought by the absence of friction would be bad, however. As stated above, some advantages of a frictionless world would be that engines and machines would no longer need coolant and lubricant (Goulding). Also, whatever moving vehicles that were invented in this frictionless world would not have to contend with drag and air resistance. An interesting change that would come about is that all metals would become superconductors (Krim). Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures, characterized by exactly zero electrical resistance (Superconductor). Since friction creates heat, there would be no heat so the very low temperatures would be present. Also, no friction means there would be zero electrical resistance (Krim). Since there are many applications of superconductivity, this would be beneficial.

Overall, the absence of friction would cause many changes: some good, and some bad. On the whole, however, life would probably be more difficult without friction. The biggest problem would be the absence of heat. Without heat, humans and most species of life would die. Aside from that, movement would be difficult and the human race would die out eventually anyways due to the fact that we could no longer procreate. I would not want to live in a world without friction.

Works Cited

Goulding, Patrick. “Applied Physics.” 18 Nov 1998. The University of Hull. 11 Nov 2008 .

“Superconductor.” Unabridged (v 1.1). Random House, Inc. 11 Nov. 2008. .

Krim, Jacqueline. “Superconductors.” NCSU Department of Physics. 12 June 2002. NCSU. 11 Nov 2008 .

A World Without Friction Essay

What is Sublimation Essay

What is Sublimation Essay.

1. Sublimation The transitions of a substance from the solid phase directly to the vapour phase, or vice versa, without passing through an intermediate liquid phase.

2. Sublimation is the process of a solid changing form a gas to a solid without going to the liquid state and vice versa. An example of sublimation is the ice cubes in freezer over a period of time they will begin to sublimate due to the temperature. This also happens when you place your clothes on a line outside when it is below freezing.

The water freezes then sublimates and your clothes will be dry but very cold.

There is one gas that changes to a solid directly at -109 degrees Fahrenheit and that is carbon dioxide. a gas can go to a solid if at the right temperature but some are very low to go directly to a solid so for an easier process they got to the liquid state by going to a higher temperature , so that then it can be frozen and then begin to sublimate example: Helium transforms to a liquid at -452.

What is sublimation explain with an example?

1 degrees Fahrenheit, if then frozen while in the liquid state it will then turn out to be a solid and begin to sublimate over a period of time. Hydrogen transforms to a liquid at 422.9 degrees Fahrenheit. If at that point in time it is frozen to a solid, that phase will start to sublimate over a period of time into a gas.

What is sublimation give three examples?

3. Sublimation (in chemistry) is the process by which a solid is converted on heating directly into a gas, without going through a liquid state. Only a small number of solids sublime, carbon dioxide, CO2 and iodine, I2, being examples. Ammonium chloride, NH4Cl, sublimes on heating, but the vapour is a mixture of ammonia, NH3, and hydrogen chloride, HCl; on cooling, solid ammonium chloride is reformed. Some solids, which do melt to form a liquid, still evaporate quite rapidly if kept below their melting points; iodine and sulphur are examples. This is also sublimation, and can be used as a method of purification.

What is Sublimation Essay

Australian ecotherms and endotherms Essay

Australian ecotherms and endotherms Essay.


1- The cat, human and platypus could be described as true endotherms, as they all maintain a relatively constant internal body temperature that is independent of the external temperature. As the environmental temperature rises from 5C to 40C, the humans body temperature remains constant, the cat’s and the platypus’ increases by around 3▫C.

2- The lizard and echidna are ectotherms as their body temperature fluctuates according to the temperature of the external environment. The lizard’s body temperature rises by 25C and the echidna by 10C as the external temp rises.

3- All animals are either clearly ectotherms or endotherms apart from the echidna. Although the body temperature of this animal increases with the external temperature, it does not increase as clearly as the lizard’s. An explanation for this could be that the echidna maintains a higher level of ability to control over internal temperature than the lizard, which has a very limited ability to do so.

4- All enzymes and other molecules function within a limited temperature range. Unless the body temperature is maintained at these optimal conditions, the rate of enzyme-catalysed reactions decreases and the organism will not function properly.


Observation Explanation Type of adaptation

Echidna’s living in cold regions hibernate during the winter Hibernation is used to keep the animal’s body temperature constantly warm by removing itself from the cold environment Behavioural

Your skin often looks quite flushed on a hot day This is due to the vasodilation of arterioles Physiological

Many Australian marsupials salivate and lick their fur on hot days Saliva is used as a way to cool down, much like sweating Behavioural

Whales have a thick layer of blubber under skin This layer provides insulation from the cold water Structural

You tend to feel cooler on a hot dry day then on a humid day of same temperature This is as the moisture in the air on humid days does not allow the evaporation of sweat to keep body cool Physiological

A small mammal, with same body temp as a larger mammal looses more heat than the larger This is due to the fact the small mammal has a larger SA:V ratio. More skin is in contact with the environment, compared to size, thus it looses more heat Structural



5- The breathing rate remains constant from 0 – 34*C at a rate of 40 breaths per minute. When the external temperature increases from 34*C onwards the breathing rate increases rapidly from 40 breaths per minute to 160+, an increase of 400%.

6- In extreme temperatures potoroos will increase their breathing rate as a method of temperature regulation.

7- Another adaptation of the potoroo for temperature regulation is the fact that it is nocturnal. The animal “sleeps by day in a nest of vegetation”, thus sheltering itself from the heat of the day. It feeds and undergoes activities in the cool of the night.

8- This is a behavioural adaptation.


9- The graph shows evidence that echidnas enter a state of torpor. The sluggish inactive periods of torpor are seen where the body temperature is low at about 10*C. These periods of torpor are interrupted by large bursts of activity demonstrated by the body temperature increase to 30*C. This is consistent with the activity of an animal in a state of torpor.

10- An echidnas heart rate, oxygen consumption and overall metabolic rate when in torpor would be much lower that when the echidna was active.

11- Torpor allows the echidna to stay inactive during most of the cold winter months, meaning that they shelter from the cold. Levels of activity in the cold weather are kept to an absolute minimum for survival.


12- The kangaroo (endotherm) – A kangaroo has the ability to change the pattern of blood flow to allow cooling. This is a characteristic of many desert animals, who’s extremities are designed to help in heat loss. The Kangaroos forearm has a dense network blood vessels that dilate in hot conditions to increases the blood flow to the forearms, which allows the blood to come in close contact with the external environment, resulting in cooling of the blood. (NB: think SA:V ratio) The kangaroo also has behavioural adaptations to assist in cooling, such as licking forearms, which act like radiators for heat loss and sheltering from the sun. The light coloured fur also reflects the heat of the sun.

Locusts (ectotherm) – The locust relies mainly on sunbaking to raise and lower their blood temperature. In the early morning, locusts turn side onto the sun to present a large surface area and thus absorb as much heat energy as possible. In the heat of the day however, they directly face the sun, minimizing the surface area and thus also minimizing heat absorption in the hottest part of the day.

13- Some disadvantages of being an ectotherm are –

*As cannot maintain constant body temperature, the day to day activity is greatly based on gaining or loosing heat energy according to changing conditions in the environment

* When environmental temperatures are low, the activity of ectotherms is also low as the metabolic rate is low

* The ability of endotherms to maintain constant body temperature allows for a broader geological and ecological distribution than that of ectotherms, who can often only survive in specific environmental conditions

Some advantages of being an ectotherm are-

*More efficient in aquatic environments as they are adapted to the constantly cold temperatures and thus there is no need to regulate body temperature.


There are a number of adaptations that both endotherms and ectotherms use to maintain a constant body temperature, many of which depend on the surrounding environment. There are three types of adaptations:

Structural- relates to the way an animal is built, eg circulatory systems, body size

Physiological- relates to the way an animal functions/operates eg. Production of hormones, sweating

Behavioural- relates to the way an animal responds eg hibernation, burrowing

A distinguishing feature between ectotherms and endotherms is that endotherms are able to regulate temperature using a feedback mechanism that involves the hypothalamus, which is a physiological adaptation. Ectotherms are unable to do this, so their adaptations tend to be mainly behavioural and structural.

Adaptations used to regulate body temperatures


Structural In water *blubber is used for insulation.

*thick fur of feathers. No adaptations needed

On land *in hot environments have large SA:V ratio to increase heat loss

*Fur and feathers provide insulation

*In hot environments have large SA:V ratio to increase heat loss

Physiological In water *secrete oil that coats fur/feathers. Insulates skin from water and prevents heat loss by conduction No adaptations needed

On land *Changing patterns of blood flow

*cooling via evaporation of water


Behavioural *Seeking shade, sometimes through use of burrows. *Sunbaking

*seeking shade through use of burrows

*being nocturnal, thus being active in cool of night.

*hibernation – lizards = torpor, insects = diapause.

Australian ecotherms and endotherms Essay