Category: Uncategorized

Galileo Galilei came up with the famous falling objects experiment to prove that objects accelerate at the same rate. All falling objects do accelerate at the same rate in a vacuum; however, in the presence of air resistance the condition will change. Our experiment considers how air resistance has an impact on the velocities of different objects. After our team finished designing the experiment, we went to present it at Dorchester Academy and Tech Boston for high school students. The blog will discuss the theory, procedure and the result of our experiment, in addition to the students’ reactions.

                           

 

Theory:

The hypothesis of this experiment depend on how we visualize things around us. We would think if we drop two objects of different weight from the same height the heavier object would fall faster than the lighter object, right? Therefore, we’re saying that the velocity and acceleration of objects depend on their mass. The experiment will explore if that is true or not, if not then we will look at the reasons behind that.

 

Set-up:

To perform the experiment we used two light sensors, different objects and an NXT “robot” that our professor helped us to program. The program basically allowed the sensors to detect the object and see how long it takes to reach the ground. The distance between the sensors was added to the program in order for the NXT to calculate the velocity of the objects. The picture below illustrates on how does the program work.

The experiment is really easy to do. It’s just placing different objects few centimeters above the first sensor then dropping them.

 

Result:

To do the experiment we used a book, hat and a paper, and the result we found was that heavier objects had greater acceleration than the lighter ones. Also, we found that air resistance is proportional to the velocity, the more the velocity, the higher the air resistance will be. When we considered the weight, we realized that the more the mass, the lower the effect of air resistance will be. Also the larger the surface area, the larger is the effect of air resistance. This concept can be applied in designing devices like cars, trains and airplanes to reduce the effect of air resistance and increase the speed of the vehicles.

The following like shows the experiment

http://www.youtube.com/watch?v=z_sJ15feNGw

 

Presenting the experiment to high school students really helped us to understand the concept even more. They did not know how the air resistance relates to our daily life. We had to explain it in different ways to deliver the correct concept to them. Most of them actually thought that the velocity of the falling objects depended on the mass, where in fact it did not. The effect of the air resistance is what really controls the speed of the objects. The students asked questions that opened our minds and made us think more about our experiment. We learned from them as they learned from us. The experience was fun and we had a great time with the students.

 

 

 

Our Presentation:

http://prezi.com/vuxhsvt1desk/falling-objects/

 

Hyperlinks:

http://www.vernier.com/experiments/psv/40/falling_objects/

http://physics.ucr.edu/~wudka/Physics7/Notes_www/node49.html

http://www.juliantrubin.com/bigten/galileofallingbodies.html

The Keystone XL pipeline is a pipeline system that transports synthetic crude oil from Canada to the to the Gulf of Mexico. The project needs to cross international borders; therefore, in order for it to be done they need to get approval from some countries. One of these countries is the United State, where the project will bring energy security and economy strength to them. The Keystone XL pipeline will allow both Canadiens and Americans oil producers to more access to the oil refining market. Also, the project will help to reduce the U.S dependence on oil from Venezuela and the Middle East by 40 percent.

 

However, this pipeline system is facing criticism from environmentalists. Although the project will provide more jobs, deliver $800,000 or more a year and rise the economy, it has some negative effects. Any leak from these pipelines will cause a huge damages. If the oil leaked into the water and the ground, it will affect the environment and the farming operation. On the other side, the Keystone XL pipeline routes will help to ship 25 percent of the oil through the pipelines, which is less expensive.

 

 

http://keystone-xl.com/about/the-project/

 

http://www.newyorker.com/reporting/2013/09/16/130916fa_fact_lizza

 

http://www.omaha.com/article/20121204/NEWS/121209837/1707

 

Falling Objects Experiment

 

Purpose:

The purpose of the experiment is to study the velocities of two different falling objects and see if they accelerate at the same rate or not. Also, we will look at air resistance and what impact can cause on the object’s velocity.

 

Hypothesis:

We would think if we drop two objects of different weight from the same height the heavier object would fall faster than the lighter object, right? The experiment will explore if that is true or not, if not then we will look at the reasons behind that.

 

Experimental Variables:

Independent variable: “Object Weight” we will change the object’s weight every time we drop an object.

Dependent variable: “Velocity” we will look at how the velocity of the two objects will change when changing the object’s weight.

 

Controlled Variable:

The controlled variable will be gravity, as we know earth gravity cannot be changed. Objects have gravity all time and this force pulls objects to the center of the earth.

 

Materials:

The materials needed for the experiment are two objects of different weights, motion detector or NXT with two light sensors and a labview “photogate_sensor”.

 

Procedure:

1) Place the two light sensors on a holder, the distance between the sensors we used was 38cm.

2) Connect the sensors to the NXT.

3) Connect the NXT to the computer and download your program.

4) Place the object you want to drop a few centimeters above the first sensor.

5) Press run on the NXT and drop the object.

6) Collect the data for the velocity and the time the objet took to hit the ground.

 

Measurements/Observations:

Book Velocity: 196.89 m/s

Paper Velocity: 114.11 m/s

It’s obvious from the data we collected that the velocity of the book is bigger. When we drop an object there are two things we look at, weight and air resistance. The result we found was that air resistance is proportional to the velocity. The more the mass, the higher the air resistance will be.

 

Demand response is a program used by some electric grids that allows consumers to help in reducing the electricity used at the peak times of the day. It is designed to respond to the peak demand periods fiscally and environmentally. The energy saved can be reused when natural disaster occurs. Most power plants offer financial incentive for consumers and businesses who participate in reducing electricity usage when the demand is high. Demand response does not only help in saving money but also it has some positive benefits serving the environment. This technology transfers power from one source to another and lower the power consumed. This has a big role in reducing pollutants that affect the environment such as greenhouse gases. Demand response is a good way for us to take an action towards energy consumption. It is basically telling the people that they are using electrical devices at the peak hours. However, if they waited for a few hours the demand will be less. Next time you want to use an electrical device look at the clock, is it a peak time?

 

http://science.howstuffworks.com/environmental/green-science/demand-response.htm

 

http://www.pge.com/en/mybusiness/save/energymanagement/whatisdr/index.page

 

http://0-www.sciencedirect.com.library.law.suffolk.edu/science/article/pii/S0301421513004539

 

In our first meeting for the final project, we had a long discussion on what experiment would be the most interesting for high school students. The choices varied between us but finally we agreed on doing the falling objects experiment. The experiment shows how two objects fall differently and how we can relate it to energy and sustainability. Air resistance is an important factor in the experiment because it can affect the rate of the object fall. Also, we will look at the velocities of two different objects. We hope the students find this experiment informative and interesting to watch.

In this lab, we looked at the relationship between the voltage and light intensity using solar cell. For the experiment we used solar cell, voltage probe, NXT adapter, NXT with light sensor, light source, ruler and colored filters. A solarlab view also was used to measure the voltage and the light intensity of the solar cells.

In the first part, we studied the relationship between the voltage and the light. First, we measured the voltage of the solar panel with no light. Then we used the ruler to place the light source at different distance from the solar panel. This gave us the difference in the voltage generated. After getting the data, we calculated the average of the numbers we got to draw the graph. The result was, as we increase the distance between the light and the solar panel, the voltage will decrease. The table below shows the data we got and the graph demonstrate the relationship between the light intensity and voltage.

 

 

The second part was to look at the relationship between the wavelength of light and the voltage of the solar cell. We held three different color filters in front of the solar panel and placed the light source at the same distance. After we found the data, we calculated the average to demonstrate the relationship in the graph. The result we noticed was without using the color filter the voltage generated was higher. This is true because there were no barrier that prevent the light waves from coming through. From the three filters colored the green one produced more voltage. Below is the data selected and the graph of this relationship.

 

The Museum of Science is an amazing place to visit, you will learn a lot of cool things in a great and fun way. The most interesting things we looked at are the wind and solar energy sections. The wind energy is basically one of the renewable energy sources that has no bad effects on the environment. Wind energy is clean, free and can be found in most places. The museum actually uses wind tribunes to produce electricity. When the tribunes produce more energy than the museum need, other utilities buy these extra energy. Also, the wind turbine lab gives live data to the exhibit “Catching the Wnd” where the visitors can see and learn about this energy technology.

 

The museum also uses the solar energy to produce electricity to the theater. At the museum roof, there are photovoltaics, or solar panels, that use the sunlight to generate electricity. As the sunlight hit the cells, some of the light is absorbed by materials called semiconductors. This material makes the negative electric charges to flow into the surface of the cells. Then the charges will flow in one direction, as the cell was designed, to produce electricity. This source of energy is very important because it uses natural source and use it to serve the human needs.

In this lab we looked at Faraday’s law, which state “Changing magnetic fluxes through coiled wires generate electricity”. As we increase the change is the magnetic flux, the current and the voltage will increase. For this experiment, we used a generator, voltage probe, NXT and NXT adopter. The generator has a magnet that moves inside a coil of wire. The activity was to shake the tube and see how much power we can generate. We started with zero then as we increased the number of shakes, the voltage became greater. We collected some data to see how much power was generated based on the number of shakes we did. We repeated the experiment a couple of times with different rates of shakes. The data were presented in an Excel sheet to find the sum of the square of the voltage. After that we took the number of shakes and the sum to draw a graph. The graph illustrated that the faster we shake the tube, the greater the voltage will be.

 

 

 

Each government works to fulfill the responsibilities it has towards its citizens. One of these duties is to create a clean environment that allows people to have a decent life. The Obama administration is working on some actions to control issues concerning climate change. Some of these initiatives are cutting carbon pollution in America, prepare the country for sever climate events and leading international effort to address the global climate change.

 

Cut Carbon Pollution in America :

The Obama administration goal is to reduce the greenhouse gas emission, that lead to global warming, to take control over the climate change disasters. Now, they are increasing the generation of electricity by using wind and solar energy which indeed will help to reduce the carbon emission and pollution. Another way is by cutting carbon from power plant and use renewable energy source. Obviously, there isn’t a law to prevent plants from releasing carbon but many states and companies are shifting to cleaner sources to use.

 

Prepare the United State for the Impacts of Climate :

The concern is how to control the climate change and avoid the impacts it cause to the country. The U.S made a crucial step by releasing a climate change adoption plan. This is basically strategies to protect certain missions and programs from any climate effect. One step to prepare the people for the climate actions is building stronger and safer communities and infrastructure. Improve hospital’s capacity to serve more patients and building a stronger infrastructure that can withstand against storms.

 

Lead International Effort to Address Global Climate Change:

The Obama administration is working on the climate change actions to reduce the greenhouse gas emission. Therefore, working with other emitting countries like India and China will help to achieve the goals related to climate change. There are many actions that have been addressed with regard to climate change. Reducing emission from deforestation and forest degradation is a one which represent one third of the global emission. The Obama administration is working with other governments to make a system that reduces land use related to emission. Also, another action is expanding clean energy use and cut energy waste. Most of the emission can be assign to energy use.

The MIT nuclear reactor tour was very interesting and helped us to understand nuclear power. The tour started with a lecture by one of the staff that work at MIT. He gave us an introduction of what is a reactor and how does it work to produce energy. Then he talked about the fusion process which is basically when two atomic nuclei emerge into a heavier atomic nucleus to release energy. In order for this process to occur, high temperatures and pressures are needed. The MIT reactor uses hydrogen atoms to form helium atoms that have less mass than two hydrogen. They use light water to keep the reactor cool and heavy water as a reflector. MIT nuclear reactor is not only for energy use but for research purposes like medicine. Most people fear the nuclear power radiations and always look at the negative side ignoring the benefits the world can get from this source of energy.