Tag Archives: science

Final Project: Water Glass

Working on an environmental issue close to home has shown me the importance of cleaning up our world. Now.

I first came across the pollution at Astoria Park, Queens earlier this semester. As I walked along the shoreline I noticed the rocks gleaming in the light in an unnatural manner. With a closer look I realized that shards of glass littered every inch of the land. It shocked me to see the severe contrast between nature and man-made trash. I knew something had to be done, and people needed to be informed.

The East River is a salt water tidal estuary. It serves as a receptacle for the city’s sewage and garbage, thus making it extremely unclean. Hell’s Gate Bridge was also a major cause for pollution as it was the route for numerous industrial shipments. Fortunately, over the years, it has been preserved to now be safe for fishing, boating, and swimming. To shed light on this corruption, I decided to collect shards of glass and create a collage. By doing so, I would be able to share it with residents and strangers and start a conversation about the water that surrounds us.

When I went to the shoreline to collect the materials, I was greeted with an abundance of trash. Every step I took was met with the crunch of broken beer bottles washed up on the shore. I ended up taking 1.75 gallons worth of glass and had to stop because my bucket became too heavy. As I was leaving, I talked to a girl named Tahia who was at the nearby bus station. I showed her what I collected and explained the project I was working on. She responded, “You’d think the government would do something, but everyone just ignores it. It’s disgusting.” She is currently a junior at Pace University studying mathematics, and was very grateful for my research. Seeing her passion and gratitude for an issue such as this reminded me that my generation is ready to make a difference, and has the power to do so.

Most of the beer bottle pieces I collected were green and brown, so I thought of creating a collage of the Earth. But I decided to stick to a river, because that’s what I researched and where the pieces had come from. On the back of my art piece I posted three pictures of the site for reference. I had also scooped up some of the East River in a container to show what the trash looks like in real life. I’m not a professional visual artist, but I’m pleased with how my final project came out. The image is clear, the patterns are neat, and it showcases exactly what I wanted to bring light to. In our final Green World class, one of the students brought it to my attention how insane it is that I was able to gather so many large pieces of glass. When she had heard what I was planning to do she assumed it would be a bunch of small pieces. But seeing the final collage was impactful by the sheer largeness and amount of glass I was able to get so easily.

So, what can we do to stop this? Riverkeeper is an incredible organization that fights to defend NYC’S waterways. You can help clean up the shores, donate, or take part in any of their numerous events to protect our water. And although NYC is is striving to invest in cleaning up the water over the next ten years, it is our responsibility to be conscious of our own actions. For example, disposing excess fats and greases, diapers, condoms, and personal hygiene products in the garbage can; using the drain can cause raw sewage to overflow. And as shown through the washed-up glass bottles in Astoria Park, recycle responsibly and consistently. The health of our world matters and affects everyone. Pollution is a man-made problem and now, more than ever, it needs a man-made solution.

 

 

Understanding Heat Exchange

I had a really excellent science teacher for 9th grade “Integrated Science” class. Her name is Kathy and the thing that’s stuck with me most from her class (besides the Photosynthesis Song) is our unit on heat.

Heat transfer is shockingly simple; there are a few equations and constants which govern the exchange of all thermal energy. It’s incredibly useful to have a good understanding of heat transfer in your daily life. Here are some key terms:

calorie The amount of energy required to raise one gram of water one degree Celsius. Calorie (with capital C) means Kilocalorie, or 1000 calories. Kilocalories are the units used to measure the energy contained in food. One calorie is 4.185 Joules.
phase change When matter transitions to a different form due to addition or subtraction of heat energy. The forms of phase change are boiling, freezing, melting, evaporation, and sublimation.
convection A form of heat transfer in which heat moves through a medium (like air). For example, an oven or forced air heating system rely on convection.
conduction A form of heat transfer where heat moves through an object. When your teaspoon heats up after being immersed in a hot beverage, this is an example of conduction.
radiation A form of heat transfer in which waves of infrared light transmit heat to the surface of an object. When the sun heats up the surface of your car, this is radiation.
conservation of energy In a closed system under normal circumstances, energy is never created or destroyed. This is a fundamental law of physics. This means that heat never disappears, it simply moves around. From this, we may infer that heat lost must equal heat gained. For example: As your cup of tea cools down, the mug, saucer, and air in the room become warmer.
specific heat capacity The amount of energy a particular material can store. Water has a specific heat capacity of 1 calorie per gram; Aluminum is more like 0.2 calories per gram.
temperature The average heat of the particles which make up a substance. Measured in degrees.
heat The total amount of thermal energy contained in a substance. If you have a bucket and a cup of water, both at 20°C, they have the same temperature but the bucket has much more heat because its mass is greater.
Q=MCΔT  That weird triangle thing is the Greek letter delta, which is scientific shorthand for change or difference. This is the fundamental heat transfer equation. Heat (Q) is equal to the mass of the sample (m) multiplied by the specific heat capacity of the sample (C) multiplied by the change in temperature (ΔT).

Say you want to know how much energy it takes for your freezer to make an ice cube. Q, the amount of energy, is our unknown. Assume the mass of our water is 100mL, and its current temperature is  23°C (we want to bring it down to 0). Since water’s specific heat capacity is 1 calorie per gram, this makes the math really easy. Q = (100gr)X(1cal/gr)(23°) = 230cal.

I’ve noticed that many people have trouble grasping the fact that liquid water can never (under standard atmospheric conditions) get hotter than its boiling point of 100°C. Assume you have a pot of water simmering on the stove at 100°C. If you turn up the heat all the way, the water will not get hotter, it will simply evaporate more quickly.

A real life example: Some friends of mine live in an apartment with old-fashioned radiators for heat. They were concerned that paper or other flammable items placed near the radiator might combust due to its heat— this seems like a sensible fire safety precaution. But since the radiators use heated water and/or steam to distribute heat, it can never get hot enough to cause a fire. Feel free to store your books on the radiator— but don’t try this with any other form of heating device! Counterintuitively, radiators do not employ radiation to transfer heat. Instead, heat is transferred from the hot water to the metal pipes via conduction which in turn heats the air through convection.

Imagine you have a container full of hot steam and a thermometer. You put the container into the freezer, and check the temperature every minute or so. If you were to plot the time and temperature on a graph, you’d get something like this:

 

When the line is flat, the system is undergoing a phase change. While the phase change is in progress, the temperature does not change because all the energy is being used in the phase change. Once the phase change is complete, the temperature will continue to change until the next phase is reached. The system reaches equilibrium when the stuff inside the container is the same temperature as the environment outside the container.

Ever wonder how scientists measure the amount of Calories in your food? Remember that the process by which your body converts food into energy is not so different than how a fire converts fuel to heat. Scientists place a sample of food, for example 100grams of butter, into a machine called a bomb calorimeter. Under ideal, high-oxygen conditions, the sample is burned rapidly. It heats a known mass of water, and the change in temperature is measured. Just solve for Q and you’ve got your nutrition facts! Of course, once you know the heat energy contained in known masses of common ingredients like oil or flour, you can just add them together to find how many calories are in your tortilla chip. Probably easier than setting it on fire.

I think understanding the basic physical laws which govern energy exchange is important in daily life. If you understand heat transfer and phase changes, you can better understand the energy consumption of tasks like cooking or making coffee. Remember that calories or joules (units of energy) can be converted to watts per second/minute/hour (units of work). I imagine that it will become increasingly important as melting ice (a phase change if there ever was one) continues to affect our planet’s habitability. Take some time to brush up on your 9th grade science!

In case this wall of text was too much for you, here are some videos to help you understand.

The inimitable Bill Nye (30min episode):

Chemistry Lesson: Heat and Specific Heat Capacity (not quite so fun, but simple and informative). 12 minute presentation.

Doc Physics- Latent Heat of Fusion and Vaporization (9min)