See You Again

Physics Investigation: The Rotational Speed of a Windmill and Wind Direction

“Windmills in my mind

spinning silky webs serene

sensuous colors…”

Those are a few lines from the poem “Windmills in My Mind” by poet Melanie Bishop which describes the beautiful appearance of windmills.

Huge and tall windmills are relatively new creatures for people who live in big cities. Several months ago when I was visiting the Chongming Island, an ecological island near urban Shanghai, I was attracted by those windmills standing high up the sky. When there was a burst of wind, the windmills start to rotate slowly and gently. And every time it rotates, I was fascinated by that. I don’t know why. But sometimes there is no need for a reason.

A windmill is a mill that converts the energy of wind into rotational energy by means of vanes called sails or blades, according to Wikipedia. From Physics’ perspective, a windmill converts the kinetic energy of the wind from the air to the kinetic energy on its blades so that they move. The blades then rotate the turbine and finally kinetic energy is transferred to electrical energy by the generator. When the windmill rotates, it does a centripetal motion. Normally, the faster it rotates, the more kinetic energy the blades have (we does not consider the case when the wind speed is too high since then it will stimulates its protection mechanism).

Windmills have a very long history. Centuries ago, windmills usually were used to mill grain and pump water. Modern windmills are usually used to produce electricity. Therefore, windmills are an important sign which shows that human beings make good use of renewable and green energies.

However, from Physics lessons we learnt from school, I find that wind power has a lot of limitations. For example, the power output is highly affected by various environmental factors, such as the wind speed. In addition, even though we assume that we have very stable wind speed, the wind direction changes all the time, and will affect the power output of the windmill.

THE RESEARCH QUESTION

According to the knowledge in Physics lessons, the output of wind power is only affected by two factors: the area of the blades and the wind speed. However, in real world, not all wind comes 90 degrees directly into the blades, and the varying wind direction (or the angle the direction of the wind deviates from 90 degrees) must also have an impact on the rotational speed, or the power output of the windmill. Therefore, my research topic is “What is the relationship between the wind direction in horizontal and the rotational speed of a windmill?”. The topic is very worthwhile since we need to decide the location of a wind power station and the direction a windmill faces to, according to the most common wind direction in that specific area. If we wish to build an efficient wind power station, we have to investigate how will the wind direction affect the power of the windmills.

EXPERIMENTAL VARIABLES

Since I only want to investigate how the angle (wind direction) affects the rotation speed, I have to eliminate other factors that may influence the results of the experiment. For example, the original speed of the wind and the distance between the wind origin and the blades must be kept constant. In addition, since we only wish to change in the wind direction in horizontal, we need to make sure the wind direction does not change in vertical. Other factors such as the air resistance and the external temperature must also be kept unchanged.

In this experiment, the independent variable is the angle the wind direction deviates from 90 degrees in horizontal. The dependent variable is the speed of rotation of the blades on a windmill. I change the independent variable, the angle (direction), and examine how the dependent variable, the rotational speed, changes in response to the independent variable.

EXPERIMENTAL DESIGN

The purpose of this experiment is to test the relationship between the angle the wind direction deviates from 90 degrees in horizontal and the rotational speed of the windmill.

I prepare all the following equipments needed to finish this experiment:

  • To make sure the original speed of the wind is constant, I need a hair drier and always set it to the LOW power output. (Though I do not know the exact wind speed, it does not matter because the change in wind speed is not considered in this experiment)
  • To measure that the the distance between the wind origin and the blades is constant, I need a 1-meter-long ruler with clear scales on it.
  • I need a motion sensor to test the rate of rotation of the blades on the windmill.
  • A big protractor is required to measure the angle between the wind origin and the blades.
  • Two retort stands are needed to fix the positions of all the equipments.
  • And of course, I have a colorful toy windmill with four blades.

The draft of the graph of my experiment is the following: 

EXPERIMENTAL PROCESS

  • First, I attach the windmill to the first resort stand, and fix its position including its height.
  • Then I setup the sensor on the first resort stand and make sure that the four blades of the windmill can all pass through the sensor when they rotate without touching the sensor.
  • After that, I attach the ruler to the first stand in the horizontal direction. The ruler must make a right angle with the stick of the stand.
  • In addition, I need to make sure the front opening of the hair drier (where the wind comes from) always perfectly points at the center-point of the four blades even though I change the wind direction, so that four blades can receive equal amount of kinetic energy.
  • Then I attach the hairdryer to the second resort stand, fix its position tightly including its height, and make sure that it cannot be moved in all directions.
  • Finally, I power on the hair drier, set it to LOW power to make sure the wind speed is unchanged, and change the angle according to the readings on the protractor by moving the second stand around. Each time I change the angle, I make sure the distance between the hairdryer and the blades keeps constant at 40 cm by using the readings on the ruler.
  • The different angles I pick are 0, 20, 40, 50, 60, 80 and 90 degrees.
  • I measure the rotational speed 3 times for the same wind direction (angle), and then use the average to plot the data. Repeating experiments makes my data and results more accurate.

 

DATA COLLECTION

The sensor is connected to the Verner Lab Pro interface and then is connected to the computer. The Logger Pro software automatically senses the motion sensor and displays graphs axes of rotational speed against time on the screen in the form like this:

The following table shows the results of the experiment:

Angle (degrees)Rotational speed (ms-1) – Trial 1Rotational speed (ms-1) – Trial 2Rotational speed (ms-1) – Trial 3
00.70470.70890.6719
200.63320.66710.6557
400.54630.52990.5632
500.45930.48220.498
600.42470.45620.4246
800.25360.26550.2312
900.13170.12020.1035

 

DATA PROCESSING

Mean rotational speed = (V1 + V2 + V3) ÷ 3

For example, the mean rotational speed of trial 20° is:

(0.6332 + 0.6671 + 0.6557) ÷ 3 = 0.6520 ms-1

Uncertainty = (Vmax – Vmin) ÷ 2

For example, the uncertainty of trial 40° is:

(0.5299 – 0.5632) ÷ 2 = 0.0167 ms-1

Angle (degrees)Mean rotational speed (ms-1)Uncertainty (ms-1)
00.69520.0185
200.65200.0170
400.54650.0167
500.47980.0194
600.43520.0158
800.25010.0172
900.11850.0141

 

DATA ANALYSIS

The mean rotational speed (ms-1) is graphed against the angle (°) in the following diagram:

I try several different kinds of function relationships to fit the data, and find that a cosine function fit the data the most perfectly because the curve is able to cross all the error bars of the data on the graph. The correlation is 0.9984, which means that the data fits this curve very well.To prove that there is a cosine relationship between angle and rotational speed, the cos(mean speed of rotation) or cos(V) is now also graphed against the angle (°) in the following diagram:

From the graph below, I find that the cosine of rotational speed is proportional to the angle which deviates from 90°, which proves that my judgement is correct. Therefore, the rotational speed of the blades does have a cosine relationship with the angle.

Using the findings from the graphs, I also use the following methods to further prove and illustrate the cosine relationship between rotational speed and angle.

From the knowledge I learnt from Physics lessons, I know that:

P = 0.5ρAv3

(Where P is the power output of the windmill, ρ is the air density, A is the area of the blades, and v is the wind speed.)

However, in this formula of power (or rotational speed, which is the same in this case), it is assumed that the wind comes 90 degrees directly into the blades, which is not always possible.

In the graph below, V1 is the real wind speed where there is a deviation, V2 is the v in the formula P = 0.5ρAv3, and α is the angle that deviates from 90° (which is the independent variable in my experiment). Therefore, it is found that if there is a deviation from 90°, only a part of the wind speed will be useful in pushing the blades moving around.

And the relationship between V1 and V2 can be derived by:

cos(α) = V2/V1

V2 = V1 cos(α)

And this illustrates why there is a cosine relationship between rotational speed and angle.

 

CONCLUSION

From the first graph plotted, we can deduce that the rotational speed of a windmill has an cosine relationship with the angle of the wind which deviates from 90 degrees. As the angle of the wind which deviates from 90 degrees increases, the rotational speed of the windmill decreases.

If we graph the rotational speed against cosine value of angle, we can find that the speed has a linear relationship with cos(α). This also proves that he rotational speed of a windmill has an cosine relationship with the angle of the wind which deviates from 90 degrees.

 

EVALUATION

Though the data does show an exponential relationship, the data is not accurate enough. When we are collecting the data of rotational speed, we find out that for the same angle, the rotational speed fluctuates a lot. Every trial has a large difference from the other ones for the same angle. Because originally I did not have any equipment to fix the position of the hair drier, I had to do that by man power. This meant that we were not able to make sure that the front opening of the drier (where the wind comes from) directed precisely at the mid-point of the four blades. In addition, human hands may shake a lot during the experiment. Therefore, I could not make sure that the direction of the wind was always constant. The rotational speed may change due to the change in wind direction. After I realized this problem, I used another stand to fix the position of the hairdryer, and the situation became much better. In addition, since the air conditioner was on in the lab, the data could be affected a little bit.

 

IMPROVEMENTS

I can make some improvements to make the data in the experiment more precise or complete:

  1. I can do the experiment in a perfectly windless indoor room to avoid some fluctuations because of the change in strength of airflow.
  2. I can also do further experiments in the future to find how other factors influences the rotational speed of the windmill. For example, I can investigate the distance from the wind origin to the blades, or the direction changes in vertical instead of horizontal.

Comment on Russia’s interest rate cut on lower-than-expected inflation

The Russian central bank lowered its key interest rate by 0.25 percentage points to 9.75 percent on Friday, citing lower inflation and economic recovery.

“The Board of Directors notes that the inflation slowdown overshoots the forecast. Inflation expectations continue to decline and economic activity recovers,” the bank said in a statement. The Russian central bank has lowered its key interest rate by 0.5 percentage points to 10.5 percent in June 2016 in a first reduction since August 2015 and further cut it to 10 percent in September.

The central bank said Friday that Russia’s year-on-year consumer price growth slowed down to 4.3 percent in the first 20 days of March from 5 percent in January.

Russia’s inflation hit a record low of 5.4 percent in 2016, sharply recovering from 12.9 percent in 2015. The target set for 2017 is 4 percent.

The inflation slowdown was broadly facilitated by the rise of the ruble on higher-than-expected oil prices and the continued interest of foreign investors in Russian assets, the central bank said.

Bumper harvests of 2015-2016 have resulted in high stocks of agricultural products, leading to a material slowdown in food, vegetable and fruit prices, it added.

The pace of Russia’s economic recovery was also quicker than previously expected, the statement said, citing growing industrial output in the first two months of 2017 and a gradual rebound in investment activity.

The central bank expected Russia’s GDP to grow 1-1.5 percent this year and by 1-2 percent in 2018-2019 considering the current dynamics of the recovery and higher economy resilience to fluctuations in external economic environment.

The Russian economy began to contract in 2014 mainly due to weak oil prices and Western sanctions over Russia’s alleged involvement in the Ukraine crisis.

Official data showed that Russia’s GDP fell by 0.2 percent year-on-year in 2016, compared to a 2.8-percent decline in 2015.

(Source: http://english.sina.com/news/2017-03-24/detail-ifycsukm3522531.shtml)

The Russian central bank lowered its interest rate to 9.75 percent recently, and this was not the first time in recent two years. The central bank has lowered its interest rate to 10.5 percent in June 2016 since August 2015 and further cut the rate to 10 in September. The bank said the reduction would help the inflation rate of Russian economy back to target. The Russian economy is experiencing an inflation, a general increase in price level.

The current inflation in Russia is mainly due to high oil prices, according to the news. Oil is crucial to every economic activity. Therefore, an increase in oil prices leads to a rise in cost of production, shifting the short-run aggregate supply to the left (from SRAS1 to SRAS2). This is shown in Diagram 1. Aggregate supply is the total amount of goods and services an economy can produce at each price level.

Diagram 1

This leads to an increase in general price level (from PL to PL1) and a decrease in real GDP (from Y to Y1). This kind of inflation is regarded as a stagflation, a negative combination of recession and rising price level. Consumers with fixed wages may lose buying power due to the high inflation as now the goods and services are at higher prices, but their wages have not risen. For people who has large savings, their value of deposits may decrease. All these lead to people’s low willingness to buy, and therefore cause an insufficient aggregate demand. Fortunately, according to the news, thanks to the increasing high interest from foreign investors in Russia, the foreign trades have not been significantly affected.

The Russian central bank claimed that progressive decrease in interest rate could be helpful to pull the rate of inflation of the Russian economy back to target. On one hand, lowering interest rate is a monetary policy that can be useful affecting aggregate demand. Through increasing the money supply (from Q1 to Q2), central bank can manipulate the domestic interest rate (from i1 to i2). This can be shown in a demand-and-supply diagram (Diagram 2).

Diagram 2

Lowering interest rate will increase the consumption on goods and services because consumers are more likely to borrow money to do purchase if loans are cheaper. Likewise, lower interest rate also stimulates firms to increase their investment. Both consumption and investment are components of aggregate demand. Aggregate demand will increase (from AD to AD1) and GDP output will increase (from Y1 to Y). This is shown in Diagram 3.

Diagram 3

On the other hand, monetary policies may be ineffective in dealing with this stagflation. Monetary policies are demand-side policies. The Russian inflation, however, is a cost-push inflation where the cost of production is not largely affected by interest rates. Moreover, this policy may also lead to higher price level in the Russian economy (from PL1 to PL2) without increasing output, making the stagflation worse.

To encounter this problem, it may be more useful for Russia to use supply-side policies. These policies can increase the long-run output (from Y1 to Y2), shifting the long-run aggregate supply curve from LRAS1 to LRAS2. Therefore, there will be a decrease in price level from PL1 to PL2. This is shown in Diagram 4.

Diagram 4

The government could achieve that by improving the quality and quantity of factors of production. For instance, it can directly provide free education and training programs, which will improve the quality of labor and lead to lower structural unemployment since more population will be able to work. Structural unemployment means people who are seeking for jobs but have not found any because of lack of opportunities. This helps to shift the long-run supply outwards. In addition, since Russia’s stagflation is caused by high cost of production, the government can also provide subsidies, infant grants and lower corporate taxes to encourage productivity.

However, supply-side policies rely on government budget, and there will be opportunity cost. For example, cutting business taxes will reduce government revenue, and money spent on subsidizing producers may be instead used on new infrastructures. All in all, more time is needed to check whether these policies will take effect in Russia.

Comment on the stricter smoking ban from March in Shanghai

SMOKING will be banned in all indoor public venues and workplaces in Shanghai from March next year. The ban will cover hotels, restaurants, offices, airports, railway stations and entertainment venues after a new smoking regulation was approved by the Shanghai People’s Congress Standing Committee yesterday.

Under the new regulation, hotels cannot have rooms designated for smoking, and restaurants and entertainment venues will not be allowed to have smoking areas.Smoking will also be banned in government agencies’ offices, meeting rooms and canteens. Airports, railway stations, ferry ports and bus stations will have to shut down smoking rooms currently in use.

The new regulation also extends the smoking ban in outdoor areas to public venues for minors, such as primary schools, kindergartens and training institutes, children’s hospitals, historic venues, stadiums and public transport waiting areas. Performance areas such as stages and audience areas will also be smoke-free.

“The regulation aims to take a stricter control on smoking and extend the smoking ban areas to protect the public from second-hand smoking,” said Ding Wei, deputy director of the congress’s legislation department.

The current regulation, introduced in 2009 ahead of the 2010 World Expo in Shanghai, stipulated that star-rated hotels, restaurants, airports, railway stations and ferry terminals could set up smoking areas or smoking rooms. Hotels were allowed to categorize rooms as smoking or non- smoking. China has accelerated a campaign against smoking over the past year, setting to raise the wholesale tax rate for cigarettes to 11 percent from 5 percent, and banning tobacco ads in the mass media, public places, on public transport and outdoors.

The new regulation does allow for smoking areas to be set up near public venues, workplaces and transport hubs, Ding said.However, they must be away from the public and major passageways and have signs-warning that smoking is harmful to health.They will also have to be approved by the city’s fire prevention authority. Fines for breaches of the new rule are unchanged at 50-200 yuan (US$7-US$29) for individuals and up to 30,000 yuan for companies.

Law enforcement officers can fine individuals and companies on the spot if anyone is caught smoking in no-smoking areas. The new rule also encourages the public to send pictures of offending behavior to the 12345 hotline. Owners of public venues will be required to ask customers to stub out their cigarettes. If customers refuse, owners can provide evidence and report offenses to law enforcement agencies, otherwise they will face fines of up to 30,000 yuan.

“Apart from the stricter regulations, we also take the feasibility of the rules into consideration,” Ding said.Under the new rule, “the city government can make stipulations on setting up indoor smoking rooms under special circumstances,” Ding said.

Indoor smoking rooms are necessary, for instance, at companies or factories where naked flames are banned outdoors. He said companies setting up indoor smoking rooms would have to get prior approval. Indoor smoking rooms have been closed at Shanghai’s Pudong and Hongqiao international airports as well as the city’s railway stations. Outdoor smoking areas have been set up at these places.

Source: http://www.shanghaidaily.com/metro/society/Stricter-smoking-ban-from-March/

The new smoking ban in Shanghai restricts the use of most smoking rooms and the act of smoking in more open areas such as kindergartens. Shanghai has already set regulations to ban indoor smoking. Besides, last year, the government raised the tax rate for cigarettes from 5 percent to 11 percent, and banned ads in the media and public places.

Cigarettes are demerit goods whose consumption is socially undesirable due to the perceived negative effects. Cigarettes have significant negative externalities, the side-effect on the people who did not incur that effect. The consumption leads to people around who are not directly involved suffering from health problems caused by second-hand smoking. The cigarette market represents a market failure which overproduces the amount of output that the society needs where the community surplus is maximized. Cigarettes are over consumed and produced. This is shown in Diagram 1. The actual quantity consumed (Q) is higher than the optimal quantity (Q*). The vertical between MPB and MSC shows the external cost paid by the society instead of the individuals who cause the externalities.

Diagram 1

Banning smoking rooms or ads and making fines are government regulations used to reduce consumer demand, shifting the demand (MPB) curve to the left, and decreasing the quantity consumed from Q to the optimal level (Q*). This is shown in Diagram 2. However, government regulations mean high cost. For example, the labor cost of hiring someone to enforce these laws in public places are expensive. This may cause a pressure on the government’s budget. In addition, the opportunity cost of setting these regulations should also be taken into consideration. The money used to hire people may be used to build new public facilities instead. Also, the regulations may not have great effect if the laws are not strict enough.

Diagram 2

Taxation is an easy and common market-based policy to reduce negative externalities. Taxes increase the cost of production of cigarettes, reducing the supply, and eventually raising the price of cigarettes. Ceteris paribus, the demand of cigarettes decreases, showing a movement along the demand curve. Now we set that the previous market equilibrium starts from output Q and price P1. The previous 5% wholesale tax on cigarettes has already shifted the supply curve from the market equilibrium to the left. Now the new 11% tax will further decrease the supply and shift the supply curve to the left. As a result, the price of cigarettes now rises to even higher P, and the output is reduced to quantity Q2, getting even closer to the optimal quantity. This is shown in Diagram 3.

Diagram 3

However, taxation also has some difficulties.

The price elasticity of demand, measuring the responsiveness of the quantity demanded of cigarettes, is quite low. The quantity demanded only changes a little when the price changes in a higher rate. Smoking is a habit, and the spending of cigarettes is only a small proportion in people’s income. So, people will continue to buy as many cigarettes as before when the tax rises. To make sure the tax is effective to discourage smoking and achieve Qopt, it must be set extremely high, which is unacceptable because most cigarette buyers are the poorer people, and if they continue to buy, most tax will be paid by the poor but not the rich, causing more income inequality. Generally, the new 11% tax may not work well in reducing negative externalities because the rate is still not high enough to force people give up smoking.

In addition, the tax rate is difficult to set appropriately because the value of negative externalities is hard to determine. It is hardly possible to measure how much the consequences such as health problems will cost. Whether the tax rate is reasonable for helping correct externalities is unknown.

Furthermore, the reducing demand and the rising price of cigarettes will definitely decrease cigarette output, lowering firms’ profits. Workers are more likely to lose their jobs if the firms cut workforce. As a result, the unemployment rate may increase. And the unemployment pension paid to the workers will exert a pressure on the government’s budget.

In conclusion, the government should evaluate different costs and consequences of every new regulation and market-based policy for discouraging cigarettes. There is no doubt that it is impossible to turn the cigarette market into a perfectly optimum level, but the government can try their best to internalize the MSB and MPB to reduce as many negative externalities as they can.

Physics Investigation: The Rotational Speed of a Windmill and Distance

A windmill is a mill that converts the energy of wind into rotational energy by means of vanes called sails or blades, according to Wikipedia. In Physics’ perspective, it converts the wind energy from the air into the kinetic energy on its blades so that they move. When it rotates, it does a centripetal motion. The faster it rotates, the more kinetic energy it has. Windmills have a very long history. Centuries ago, windmills usually were used to mill grain and pump water. Modern windmills are used to produce electricity and pump water for land drainage or to extract groundwater. Therefore, windmills are an important sign which shows that human beings make good use of renewable green energies.

Once I asked myself: “Well, the wind provides energy and forces the windmill to rotate. But in what way can we change how fast it rotates?”

THE RESEARCH QUESTION

Last week, I found a windmill in my old toy box. I tried to blow away the dusts on it. It rotates really fast. But when I was on my bed after I made it standing on my table, it rotates slowly and peacefully when I blowed. I thought of the question that I had wondered for many years since I was a child: how can the distance from the origin of the wind to the windmill affect its rotational speed? I might guess the answer, but I needed to prove that. I needed to design an experiment to examine the specific relationship.

EXPERIMENTAL VARIABLES

Since I only want to how the distance affects the rotation speed, I have to eliminate other factors that may influence the results of the experiment. For example, the original speed of the wind must be constant. The angle made by the direction of the wind and the front of the windmill must be constant too. Other factors such as the air resistance and the external temperature must also be kept unchanged.

In this experiment, the independent variable is the distance from the origin of the wind to the windmill. The dependent variable is the speed of rotation of the windmill. I change the independent variable, the distance, and examine how the dependent variable, the rotational speed, changes in response to the independent variable.

EXPERIMENTAL DESIGN

The purpose of this experiment is to test the relationship between the distance from the origin of the wind to the windmill and the rotational speed of the windmill.

I prepare all the following equipments needed to finish this experiment:

  • To make sure the original speed of the wind is constant, I need a hair drier and always set it to the LOW power output. (Though I do not know the exact speed of wind, it does not matter because it is not the factor involved in this experiment)
  • To measure the specific distance from the hair drier and the windmill, I need a 1-meter-long ruler with clear scales on it.
  • I need a motion sensor to test the rate of rotation of the windmill.
  • Two retort stands are needed to fix the positions of all the equipments.
  • And of course, I have a colorful toy windmill with four blades.

EXPERIMENTAL PROCESS

  • First, I attach the windmill to the first resort stand.
  • Then I setup the sensor on the second resort stand and make sure that the four blades of the windmill can pass through the sensor when they rotate without touching the sensor.
  • After that, I attach the ruler to the first stand in the horizontal direction. The ruler must make a right angle with the stick of the stand.
  • In addition, I need to make sure the front opening of the hair drier (where the wind comes from) perfectly directs at the mid-point of the four blades so that the wind direction does not change.
  • Finally, I power on the hair drier, set it to LOW power to make sure the wind speed is unchanged, and change the distance according to the readings on the ruler by my hand.
  • I choose the distance once every 10 centimeters. The distances I pick are 20 cm, 30 cm, 40 cm, 50 cm, 60 cm and 70 cm.
  • I measure the rotational speed 3 times for the same distance, and then use the average. Repeating experiments makes my data and results more accurate.

DATA COLLECTION

The sensor is connected to the Verner Lab Pro interface and then is connected to the computer. The Logger Pro software automatically senses the motion sensor and displays graphs axes of rotational speed against time.

DATA PROCESSING

Mean rotational speed = (V1 + V2 + V3) ÷ 3

For example, the mean rotational speed of trial 0.20m is (0.756 + 0.760 + 0.765) ÷ 3 = 0.760

Uncertainty = (Vmax – Vmin) ÷ 2

For example, the uncertainty of trial 0.30m is (0.688 – 0.594) ÷ 2 = 0.047

DATA ANALYSIS

The mean rotational speed is graphed against the distance in the following diagram:

And the ln(mean speed of rotation) or lnV is now graphed against the distance in the following diagram:

CONCLUSION

From the first graph plotted, we can deduce that the rotational speed of a windmill has an exponential relationship with the distance from the origin of the wind to the windmill. As the distance from origin of the wind to the windmill increases, the rotational speed of the windmill decreases.

If we graph the ln value of the average rotational speed against distance, we can find that lnV has a linear relationship with the distance. This also proves that the rotational speed of a windmill has an exponential relationship with the distance.

EVALUATION

Though the data does show an exponential relationship, the data is not accurate enough. When we are collecting the data of rotational speed, we find out that for the same distance, the rotational speed fluctuates a lot. Every trial has a large difference from the other ones for the same distance. Because we do not have any equipment to fix the position of the hair drier on the ruler, we have to do that by man power. This means that we are not able to make sure that the front opening of the drier (where the wind comes from) directs precisely at the mid-point of the four blades. In addition, human hands may  shake a lot during the experiment. Therefore, we can not make sure that the direction of the wind is always constant. The rotational speed may change due to the change in wind direction. Further more, I did not take the distance from the wind origin to the opening of the hair into consideration of the whole distance. Instead, I used the distance from the opening to the windmill when calculating. This may have a slight influence on the results of my experiment.

IMPROVEMENTS

I can make some improvements to make the data in the experiment more precise:

  1. I can do the experiment in a perfectly windless indoor room to avoid some fluctuations because of the change in strength of airflow.
  2. I should use an equipment to fix the position of the hair drier during the experiment, so that we can make sure the wind direction does not change during the experiment and the front opening of the drier (where the wind comes from) directs precisely at the mid-point of the four blades.
  3. I should take the distance from the wind origin to the opening of the hair into consideration of the whole distance instead of only using the distance from the opening to the windmill when calculating. Therefore, the real distance should include both the distance from the wind origin to the opening of the hair, and the distance from the opening to the windmill.
  4. I can also do further experiments in the future to find how other factors such as wind direction influences the rotational speed of the windmill.

My new company project STU-CLOUD coming soon

I set up my new students’ company called STU-CLOUD with a few friends from different schools in China recently. I planned to attend the 2016 High School Changemakers Challenge contest with this project, and I have already registered. By this time, we have successfully passed the first round of selection by submitting our proposal. The next round will be the presentation on Nov.25. And I will share some information about it in this article.

In short, STU-CLOUD provides a perfect, multi-function, online campus services solution designed for students.

We hope that by using WeChat and online websites, we can abstract useful information from traditional forms in campus public services, and transfer it into a new form, so that we can improve the efficiency of using information and resources, save cost for schools, and significantly improve the students’ experience in campus. Rather than being a dumb info-taker, you can be an info-finder with ease, just like observing everything above the cloud! So what we goanna do is to build an online information center, and provide some basic services such as Second-hand goods exchange and Lost & Found.

Through our own experiences and observation, as students, we find out that most schools are not using the most effective way to solve the problems that students overcome every day. There’s no innovative way to improve students’ experience. This causes a huge waste in information and resources. Through our investigation, we mainly find three problems.

We find that students own many unused but valuable goods and resources. They just wasted them. For example, text books and electronic devices. However, none of our competitors is perfect. For instance, they are not specifically designed for students. They are also not safe enough because the society is too chaotic. And we all know lost and found. It is a very common service, but it also has many problems. First, information asymmetry. Usually, if someone find something, he can transfer the information to the public very easily. But about the one who loses something? He or she will not have a way to transfer that information to the public. In addition, timeliness. Usually if you find something, what will you do next? Ok, you can shout on the broadcast. But no. Who wants a broadcast? What if you miss that tiny ten seconds of speech? You will never have a chance to know that again. This doesn’t work, because information is not transferred in the right way. In addition, because of lack of technology and awareness, traditional schools are not willing to solve these problems by the Internet. So, it is really embarrassing so see that our schools are still so old fashioned.

So we ask ourselves: What are the solutions? What we gonna do, is to put all campus services in one online platform. Let’s first talk about Second-hand goods exchange. We will build a campus service website that is can run on PC, phone and iPad at the same time. We will build up our own Wechat account. Buyers and sellers can upload their information about the goods they want to sell or buy on their phones. Yes, only by using your phones. And you can upload description, photos, locations, Wechat and phone numbers. We even have customer relationship, and do Q&As for our customers through QQ, Wechat and emails. Second, Lost & Found. After the goods exchange platform is built, we’ll copy and change it a little bit to make an online lost and found website. We will use Wechat to present information to our users so that no one will miss it. Both people who lose or find can submit description, photos, their phone numbers and even prize on the website. The customer relationship will keep contact with both users who lose and find until the case is finished. We will also provide free deposit services.

It seems like a thoughtful method, but you might wonder if this would actually succeed. In order to make sure our success, we have short term, mid-term and long term targets. In the short-run, we will do market research. We’ve already finished that, which is quite a good start. And our tech team will build up the original form of our website. In short run, we will only provide second-hand exchange and lost and found in just one school: Weiyu High School. And the first website will be available in about one month. Three months later, we will change the website a little bit according to students’ needs and wants, and start to bring impact on the school and the teachers by advertising on social medias. In the long term, about half to one year after we get started, we will further improve it and advertise it to more schools using research and development. We hope to add more new functions, and plan to run in at least five high schools in the following year.

But there is still one more question. Why do we need STU-CLOUD? What’s so attractive about it? There are four main characteristics of STU-CLOUD. From the very beginning when we first thought about STU-CLOUD, we believe that it must be modularized. This means that STU-CLOUD is not just a single service, but a combination of many different services. So second- hand exchange and lost and found are just two of the modules of our platform. What can we do if we have a good idea in the future? We just add it! And STU-CLOUD is completely customized, so the school can DIY the modules that they want, they can just switch of the modules they don’t need. Second, it’s duplicable. Once we finish a complete solution, we can simply apply and sell it to many other schools. And I think that’s why it should have a huge impact on the society. There are so many schools and so many students in Shanghai, in China and even in the world. It is just so easy to spread it all around the world. Can you dream of that in the future, by using STU-CLOUD, any school can own such a powerful online platform in just one click? No need for hiring professional teams. No need to rent expensive servers. And we can save so much time and so many resources. Isn’t that change amazing?

So this is not just an online platform that provides campus services. We all believe that, and you must believe that this is the future, the future for the schools and the future for all the students.

Chinese council should collect recyclables from people’s houses

I think that our local council should collect paper, plastic and recyclables from our houses directly. Currently, in Shanghai, most communities that run recycling projects ask people to bring their garbage to a center in the community. And this is one of the reason why only a few people support and do recycling. First, unlike those people in developed countries, Chinese people do not have much understanding about environmentalism. Unless they are forced or asked to do so, they usually prefer avoiding those trouble because they think that is a waste of time. No one want to walk a long distance to those collecting centers every day. Collecting from people’ houses can solve this problem to some extent. In addition, people will be also reminded every time their garbage is collected, and will turn it into a habit in long run. Second, collecting from people’s house cost less in long run. It can be regarded as a kind of long term investment. If we help and teach people do garbage classification at their home when we collect garbage at the beginning, people are very likely to turn it into a habit some time later. Then there will be no need for workers to do classification and processing work in garbage centers. This will save a lot of time and labor, which is beneficial to our society in the near future.

Emissions trading: good or bad

Emissions trading is a government-mandated, market-based approach to controlling pollution by providing economic incentives for achieving reductions in the emissions of pollutants. A governmental allocates a limited number of permits to discharge specific quantities of a specific pollutant per time period. Polluters are required to hold permits in amount equal to their emissions. Polluters that want to increase their emissions must buy permits from others. There is no denying this does help decrease emissions in some developed or high carbon-emission countries to some extent. For example, the Europe Union, United States and China has already set their own regulations and markets several years ago. However, it also has many shortages and potential negative effects. First, it is not realistic enough. All developing countries highly rely on manufacturing which cannot avoid high carbon emission. If emission trading is applied on those countries, the economy development of those countries will be negatively affected. Then it will become an obstacle for the developing countries. Though it is important to cut emission, there is nothing more important than helping more people get rid of poverty. Second, it leads to high risks on the economy of a country. If we allow producers to trade permits freely, we will not be able to control the rising price of the permits. Since the quantity of emission allowed is so limited, the price will rise crazily out of control. The rising cost of production will finally lead to the decrease in supply and the rising price of final products, which makes all products on the market less affordable. Lower living standards and turbulent prices do no good to the economy.