During the course of the last week the “Contemporary Science and Innovation” class has been experimenting with Lego robots to understand: Force and Energy, Velocity and Acceleration, and Power. As mentioned in my previous blog about Lab #1 the class is completing the labs using Lego Mindstorm NXT. Which is a robotics kit that is programmable released by Lego Company in 2006 replacing their first generation kit. In this lab we used the NXT but also a Lego Mindstorm motor to lift weights with a pulley.

A pulley is a wheel, with a fluted rim for carrying a line, which turns in a frame or block and aids to change the direction to transmit force. A pulley works by altering the direction of what is called an ‘applied force’ by either changing rotation or what’s known as linear. Linear is measurement of one direction only. So that you are aware force is any influence that effects an object to undergo an alteration, either concerning its movement, direction, or geometrical construction. A force can cause an object with mass to change its velocity which begins moving from a state of rest. Velocity is the speed of something in a given direction. Acceleration is increase in the rate or speed of something. Power is defined as the amount of energy consumed per unit time. Newton’s Second Law of Motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables – the net force acting upon the object and the mass of the object.

When we got into class the lab was already set up with the pulleys so we did not have to assemble them. The VI was also set up so we didn’t have to create it (link attached under references). Some important components to note on the VI program is: read battery level, read timer, reset rotation, and write to measurement file. Ready battery level reads the NXT battery power level of the connected NXT and outputs the power level in millivolts. Read timer reads the specified millisecond timer on the NXT brick. All tiers are reset and start running when program begins. Reset rotation resets the motors connected to the specified ports and clears their internal rotation counts. Write to measurement file express VI writes data to text-based measurement files or binary files so that they can be opened in excel.

The first thing we had to do was explore Newton’s 2^nd law by keeping the power level fixed and
changing the mass. Newton’s law is f=ma. The group started with a test run so that we made sure the pulley worked without any trouble which it did. Then for the first three runs we kept the power level fixed at 50% but changed the mass or weight the pulley had to pull up. The weights used were several small pieces at about 10 grams a piece and could be added or removed as pleased. We started with the full 250 grams which calculates to the mass of 0.25 kg or kilograms which had an acceleration of 6.718 RPM/s at the time of 5.164 second. The second run was at the mass of 190 grams or 0.19 kg with the acceleration result of 14.87 RPM/s and the time of 2.864 seconds. So as the mass changed the acceleration quickened and with it the time it took. On the third run the mass was changed to 130 grams or 0.13 kg and the acceleration changed to 9.92 with the time of 4.321 seconds. This part of the experiment concluded that as the mass is lowered the acceleration and time speeds up so the pulley has to work less.

The second part of the experiment was to keep the mass the same and change the power level to see if the acceleration varies. The mass was set at 250 grams or 0.25 kg for the second run of the experiment. The first run with the power of 70% resulted in acceleration of 0.321 RPM/s with the time of 23.94 seconds. The second run with the power of 30% resulted in the acceleration of 2.585 RPM/s and the time of 6.552 seconds. And the third run at the power of 40% resulted in acceleration of 6.26mRPM/s with the time of 4.464 seconds. It is concluded that the acceleration followed a sturdy increase as the power decreased as with the time it took was considerably less.

As the class went along with the runs explained above we also followed the battery discharge versus the mass for a fixed power level. The battery discharge is how much the power was used for the experiment. The battery discharge overall decreased when the mass was decreased (so less weight) and also when the power level decreased. This is understandable because the lesser the weight the less the pulley has to work so less power is used. It took less energy for the NXT motor to move the mass up the pulley at a slower rate. The first three runs with the fixed power level but changes mass resulted in: 138, 41, and 0 for battery discharge. The next three runs with the constant mass and change of power level resulted in: 83, 27, and 13 for battery discharge.

This lab was useful in the understanding of how to make engines more capable especially car and plane engines. Maybe there is a way in the future with more testing to make cars and planes out of lighter and green material so there is less mass the engines have pull making the energy decrease resulting in energy efficiency. Also if there was a way to make all machines and machinery more effective and less of a danger to the workers, with less fossil fuels being produced then we should attempt to investigate through more experiments.

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References:

1. http://www.physicsclassroom.com/class/newtlaws/u2l3a.cfm
2. http://web.cas.suffolk.edu/faculty/lshatz/Sustainability_class/Labview/Lab2_2.vi

 

Hydro-fracking or Natural Gas Hydraulic Fracturing is the fracturing of rock by pressurized liquid to extract natural gas. The process was created by Haillburton Inc., Schlumberger Inc., and Messina Inc. in 1947. The technique is mixing sand, water, and chemicals in which the mixture is injected at high pressure into a wellbore to generate small fractures (< 1mm) along with gas such as petroleum, uranium-bearing solution, and brine water may travel to the well. Wellbore is a drill hole used for the purpose of withdrawal or examination of natural resources such as natural gases or oil where a well may be produced as resource for extended period. The most common natural gas in Shale gas which are fine-grained sedimentary rocks that can be rich sources of petroleum. Natural gas is used for 24% of America’s energy demand. It heats 51% of American households.

As of 2012 there are 2.5 million jobs available in hydro-fracking and more than one million of those jobs are in the US. Although fracking provides millions of jobs these jobs are dangerous, exposing workers to chemicals with long term effects that are still unknown to us. Many people wonder if hydro-fracking will bring the U.S. more energy independence but in fact it won’t. Much of the gas being fracked will end up in Europe because gas will flow to the highest bidder. Once the gas flows overseas the prices will rise in the U.S. and the gas prices will be dictated by the world market.

Challengers of hydraulic fracturing point to some environmental risks including reduction of fresh water, contamination of ground water, corruption of the air, noise pollution, migration of gases and hydro-fracking chemicals to the surface contamination from spills and flow-back, and also health effects. Each time they build a well they need 3,500,000 gallons of water when fracking one well. It is stated that upwards of 70% of fracking fluid remains in the ground after fracking and is not biodegradable. Researchers suspect 65 of the components used in hydro-fracking are hazardous to humans.

Natural gas is cleaner than oil and a lot cleaner than coal but it’s still a fossil-fuel that enhances greenhouse gases like methane and carbon dioxide (CO2) into the atmosphere. Although the leakage of methane outweighs the climate benefit of natural gas versus coal. Natural gas gives off 50% of the carbon dioxide emissions as coal. Methane’s warming potential far exceeds that of coal; methane traps heat up to 105 times more effectively than the mass of carbon dioxide.

Scientists have identified cancer-causing chemicals like “BTEX” benzene, toluene, ethylbenzene, and xylene and 596 other chemicals are being used in hydro-fracking, but nobody knows for sure what chemicals are pumped underground. In 2005, the Bush administration supported an energy bill that excuses hydro-fracking from the Safe Drinking Water Act. The Safe Drinking Water Act is a federal law that ensures the quality of American drinking water. The law protects drinking water and its sources: rivers, lakes, streams, and ground water wells although they do not regulate private wells which serve fewer than 25 persons. The peculiar thing is that companies that participate in hydro-fracking keep their chemical mixtures a secret to the people that allow them to engage in hydraulic fracturing on their land. This is peculiar because if they were using environmental friendly chemicals during the process of fracturing they wouldn’t have to hide the truth.

The hydro-fracking chemicals used within the mixture to help obtain natural gases becomes sealed deep underground, there’s a good chance the chemicals enter private wells destroying drinking water quality. When the natural gas comes to the surface, it carries millions of gallons of contaminated water with fracking fluid and radium that is stored in on-site ponds that can leak or overflow into streams connecting to major bodies of water. And in many other cases the poisoned water is transported to water treatment plants that cannot handle radioactive water. That contaminated water is then sent downstream to the town’s drinking water. The above serious long term threats to water quality are one of the many oppositions people have to hydro-fracking, especially in the Marcellus Shale Region where important watershed provides drinking water to 16 million people.

There are a few companies in the world that are planning an alternative to hydro-fracking by using sunlight and nanoparticles to produce natural gas from wastewater. They hope that it will alleviate the need to drill for gas using hydraulic fracturing. I believe that if we can find a safer non-toxic way to obtain natural gasses then I am all for it but not until then. I firmly believe hydraulic fracturing is not in the best way to obtain natural gases and if we continue global warming will worsen and more drinking water will be contaminated.

Videos:

Fracking Causes Flaming Taps

Fracking Hell: The Untold Story

Hydraulic Fracturing 3D Animation

Gasland

Resources:

1. Time: The Debate over Shale Gas Deepens
2. Discovery: Shale-Gas Drilling Contaminating Drinking Water
3. Energy API: Natural Gas and Its Uses
4. A Brief Chat About Fracking
5. Geology: What is Shale Gas?

Throughout the last few weeks the “Contemporary Science and Innovation” class has been

experimenting with Lego robots to understand: distance, velocity, acceleration, and force. Lego Mindstorm NXT is a robotics kit that is programmable released by Lego Company in 2006 replacing their first generation kit. The computer of the Mindstorm NXT is called the NXT intelligent brick. The intelligent brick is the brain of the machine that lets the robot perform operations you tell it to.

To be able to experiment with the cars the class had to construct them first. With our teammates we assembled the NXT motor car using the parts provided to us within our kits and the instructions on the blog. The first thing we had to attach was the motors to the intelligent brick which makes the car eventually move. Attached to the motors is supportive components and the wheel.The support is connected at the top of the motors through pegs so that the motors stay steady and don’t sway when moving. The back wheels are attached to the bottom of the motors with connector pins and the front wheel is attached creating L-beams and axel jointers. After attaching all the wheels we placed the RJ-11 cables into the two motors and the USB cable into the intelligent brick and computer.

After powering on the motor car the group went into the LabVIEW program through Windows. LabVIEW or Laboratory Virtual Instrument Engineering Workbench is a platform and development environment for visual programming language through a company called National Instruments. To make the motor run forward Within LabVIEW, click view > function pallet > NXT I/O > place motor and drag into block diagram. That makes it so the motor car has a motor but a constant isn’t created yet. To create a constant you move the mouse over the object (motor) > right click > create > constant > Port A. What this does is tell the computer that you want Port A to move or the wheel attached to Port A. Next the group created a while loo which is a control flow statement that allows information to be implemented recurrently (structure palette > selection rectangle).

If you want to make the while loop stop so that the motor car stops with the press of the orange button; you have to wire the NXT button to the stop button. This is done by clicking the NXT button and dragging the grey dotted line to the stop button. To change a constant’s power the group right clicked the constant and typed in the number needed (in this example 50). To make more functions follow the directions above (third paragraph) and then right click that constant on the blue dot to add another port function.

To save the project and download the group went to file > save > right click (on the bottom bar) > NXT > download > click orange.

The second lab is a continuation of what I talked about in the paragraphs above only we had to measure distance and velocity. Distance is scalar quantity or actual path length traveled, associated with speed. Velocity is a vector quantity meaning there is a direction. This lab is using the motor car to measure the distance the wheel traveled and the speed at which the car traveled. The first thing we did as a class was program the motor car to spin clockwise in a circle of two feet and the separate groups had to figure out what setting to have the motors run so that one wheel is turning more than the other and measure it with the ruler. This was done by measuring the circumference of the wheel (.19m) which we later plugged into the program. Subsequently running the program the group recorded how many complete turns the wheel had made and the degrees at which the wheel was rotating. Knowing the degrees at which the wheel turns lets the group know where the wheels stopped and how many turns it had made. The program (VI) recorded the distance the motor car traveled but the group double checked with a ruler. From this data above the group found the percent error for three trials at low, medium, and fast with the outcome of medium and high speeds having the least difference of measurement compared to low speeds. The formula is as follows:  (d stands for distance). Motor-Car-Turning

The lab did a wonderful job of opening my eyes and helping me understand how cars work and how we can save energy while driving. This is important information to be aware of when purchasing a car or designing a car to be economical and energy efficient. This is extremely important so we can help little by little to reduce the toxins within the air and planet to decrease the ill effects of global warming.