Electricity

For the past two weeks, our science class has been reviewing, learning, and investigating the topic of electricity. There have been eight main topics that all students were required to learn, of which included: how charges interact with one another, how charges can be transferred, electric currents, conductors and insulators, how resistance affects currents, Ohm’s law, series vs. parallel circuits, and the difference between voltage, current, and power. The class was divided into groups of three, and each group created a presentation on one of these specific topics.

One of the first things our class did was that we each had to build an electrical circuit with only a battery, a magnet, and a wire. Mine is shown on the video at the side. The point of this project was to make us understand how an electrical circuit works. An electric circuit is a “complete, unbroken path through which electric charges can flow.” The charges in an electric circuit flow from the negative side to the positive side because the electrons are negative. Negative charges repel other negative charges, just as positive charges (protons) repel other positive charges. However, positive and negative charges attract, which is why the electrons flow towards the positive side. In my experiment, the electric current (the continuous flow of electric charges through a material) flowed through the copper wires, through the copper spinner, and back through the other wire. With the force of the magnet pushing the spinner up, and the electricity causing it to move, the spinner executed its task and started turning.

The law of conservation of charge states that charges are neither creates nor destroyed, they are only passed along. Charges can be transferred through three different types of methods: friction, conduction, and induction. When objects are transferred through friction, their electrons move when the two items are rubbed together. In the process of conduction, items can be charged through direct contact, in which electrons transfer from the item with more negative charge to the item with more positive charge.  In the last method, induction, objects do not have to touch to transfer charges. It is caused by the electric fields of the objects, which either attracts or repels electrons.

The next topic is based on conductors and insulators. Conductors help ease the flow of electricity, and its atoms contains electrons that are loosely bound together. Good examples of conductors are silver and copper, like I used in my project. An insulator slows down the flow of electricity, and its atoms are tightly bound together. Good examples of insulators are plastic and rubber. Rubber is usually found wrapped around wires. This is so that when people touch the wires, they don't get shocked.

The fifth topic that we learned was about resistance. Resistance is how difficult it is for charges to flow from materials. There are four things that affect resistance: heat, material, width and length. Take, for example, two cables. One is wide and the other one is half the width, the wider cable will allow more energy to flow than the latter. In some cases, resistance is a good thing. With hairdryers, showers, etc., resistance is needed to produce the friction that causes the heat.

Ohm's Law states a simple equation, Resistance = Voltage/Current. In Ohm's Law, the greater the resistance is, the less the current is and vice-versa. Voltage is a difference in potential energy between two places in a circuit. Voltage causes electric currents because the pressure from the voltage will push the current. Sometimes, the voltage may not be enough to push the current, or it might be too much. That is why you cannot put a 220 volt appliance in a 110 volt socket, or a 110 volt appliance in a 220 volt socket. 

There are two types of circuits, the series circuit and the parallel circuit. In series circuit, the current can only take one path through all of the resistors. This means that if something goes wrong and one of the resistors burn out, the resistors that follow it will also burn out. In contrast, parallel circuits have multiple paths that a current can take, so if a resistor burns out, the other continues working. An example is with christmas lights, sometimes one of the twinkly, colorful lights stops working, and all the others behind it stop shining as well. However, if you take the lighting of a house, for example, if one of the lightbulbs run out, the others stay on. 

The last topic is the difference between voltage, power, and current. This also has an equation: Power = Voltage x Current. This means that if either voltage or current increases, so does the power.

This is basically what we've been talking about since school started, and it will be the base of what we learn for the rest of the school year. Personally, I don't understand this topic very well, and I am having difficulties. However, I plan to get better, and eventually succeed in understanding all of the topic. 

Electricity Quiz

Cells Project: Zoinks!

The goal of this project was to invent a creative way to teach kids about cells. Our invention would be added to a science kit produced by Zoinks!, a book company. My plan was to create a talk show called "The Late Night Science Show" in which the host, Tania Davies, would ask three guest stars, Eliza Peterson the Eukaryotic Plant, Ernie Armando the Eukaryotic Animal, and Patricia Popper the Prokaryote, multiple questions about cells. This works to teach kids about cells because the "cells" answer many basic questions that the consumers might have themselves. They also have many different personalities to match with their cell. For example, Eliza is British and thinks she knows everything, she is a very complex person, the cell she represents is also complex. Ernie is very laid back; he represents the animal cell, which is not as complicated as the plant cell. Patricia is very bland, she isn't very interesting, she seems to be away in her own world most of the time. She represents the prokaryotic cell, which is very boring as well and doesn't have much going on inside, without a nucleus.
In the beginning, the plan had been to use three different people to star as the guests. They would each have a cardboard saying what they were taped around their necks. I had previously thought of filming with a professional camera, but that did not work out. My final project differed greatly from what I had had originally in my mind. In the end, I ended up playing all four characters, because the people that were going to help me ended up not being able too.  I did not use the cardboard idea because the words could not be visible in the bad quality camera. The final result, though not as pretty as I had planned, turned out to be quite good.
I think that I did well on the project. It was not very good quality, and at times boring, but it contained good information, and I worked on it very hard. The filming was difficult because I had to stay in a certain spot and could not move around. The computer, which I was filming with, could not be touched or else I would have to start all over again. I accidentally moved it once, and had to start over. The editing was easier, but it took a very long time because I had to crop all of the clips. One part of the video turned out strange because I accidentally cropped a different video and didn't notice it until later. Overall, however, I think I did pretty good information wise.

Egg Lab Investigation

Introduction

In science class, we’ve been learning about the diffusion of water and other molecules through the selectively permeable cell membrane. Our Egg Lab consisted of placing two different eggs in two different solutions, one of distilled water and the other of corn syrup. This relates to our science lesson because as we observe the reaction of the egg and the liquids, we can witness an example of what happens with the cells. An example of osmosis in real life is when we eat salty things, the salt is absorbed into our bloodstream and the water within our cells transfers to the other side to create equilibrium, which is why we get so thirsty. We need the water to come back into our cells, so that we can have an equal balance of water, outside and inside the selectively permeable cell membrane.


Predictions in the Beginning of the Experiment:

In the corn syrup egg, the egg will shrink because there is less water outside the egg which causes the water in the egg to be transferred into the corn syrup.
In the distilled water egg, the egg will grow because there is more water outside of the egg than inside of the egg, causing water to be transferred into the egg.

What did my team do all three days?

                Following the instructions, on the first day my team took the measurements of the eggs and placed them into corn syrup and distilled water for the following day. The next day, we removed the eggs from their residing liquids, and measured them once again. We took notes of our observations, and once again placed the egg into their containers. On the last day of the experiment, my team got the eggs and measured them for the last time. We also measured the volume of both the distilled water and the corn syrup, as we had been the other days, and observed how much it increased or decreased from its initial 80 ML. We popped the eggs, as shown in the video below, and took notes on what we saw afterward. Lastly, we got the notes from the other team and averaged the numbers. With our results, we created graphs and began our analysis.

The Graphs

Qualitative Data:

Egg 1:

  Day 1: Egg has a yellowish color, and has a visible yolk. It has a smooth texture and seems to be very fragile. It looks like a water baloon. After applying into Corn Syrup, egg began to float.

  Day 2: Egg seems smaller. Corn syrup solution raised. The egg got a darker color, similar to the corn syrup’s golden shade. It seems more fragile, softer, and more likely to pop.

  Day 3: It has completely faded into a corn syrup-like color. It seems to be larger than it was last time, but still smaller than Egg two. 

  Popping of egg: This one just seemed to pop when touched, the yolk was solid.

Egg 2:

  Day 1: Egg 2 is a little golder than Egg 1. It is smaller and seems to be rounder. This egg has a smoother texture and seems to be less fragile than Egg 1. After being applied to distilled water, this egg did not float.

  Day 2: This egg seemed larger, fuller and less fragile. The egg has lost its golden color and has turn a peachy white color. It has probably absorbed more water, causing its loss of color.

  Day 3: The egg’s golden color has faded completely into a very white color, similar to the distilled water’s. It is bigger than last class.

  Popping of egg: This one popped and bits seemed to fly everywhere, the inside was completely liquid.

Possible Sources of Error Related to Procedure and Equipment and Solutions:

•Not everyone might have measured the circumference of the egg in the right point every single time. A solution I thought of was to measure the length of the egg, and get the circumference at the closest possible to the half mark.

•When transferring the liquids from cup to beaker to cup in order to measure it, some drops of liquid might have been lost in the process. To solve this, we coud put the liquid originally in a cup with a built in measuring tool so then we do not have to move it around.

Conclusion: 

  The goal of our investigation was to find how the egg’s membrane demonstrated an example of the cell membrane. I think that as an experiment, it really gave us a good chance to see an example of how the selectively permeable cell membrane works. With Egg 1,  the egg decreased in size after being placed in corn syrup. The egg had originally weighed an average of 72.7 grams, and after three days, it ended with an average of 69 grams. However, a strange thing that happened was that the egg had an extreme decline from day 1 to day 2, but from day 2 to day 3, the egg's mass increased. I think that this is because the egg had lost too much water, and because of its loss, had to absorb water from the surrounding corn syrup in effort to balance both sides. I conclude that the numbers decreased because the corn syrup contained less water than the egg, osmosis made sure to distribute the water to the corn syrup, so that it could have an equal concentration of water on both sides.
  As with Egg 2, which increased in size after being placed into distilled water, it also experienced a case of osmosis. As the amount of water was greater outside of the egg’s membrane, the water was transferred into the egg in attempt to balance out the inside and outside, and thus created a very large egg. The numbers show this because, in the beginning, the egg had weighed an average of 67.8 grams, and on the final day, it weighed an average of 77.5. As with the popping of the egg, I conclude that Egg 2 popped easier than Egg 1, as shown in the video above, because it was more drenched with water than the latter. In the end, the experiment showed me a very interesting concept relating to osmosis. I realized, as well, that not only did the water distribute throughout the two substances, but the color did as well. The two eggs completely lost their original color, and became an exact replica, or close to one, of their designated liquid. Another example of osmosis is when, in plants, water and nutrients enter a plants roots through osmosis, going from the area of higher concentration (outside) to an area of lower concentration (inside).


Evaluation of Team Work and What I Learned in this Investigation:

  My team worked well and collaborated nicely. We took notes, and I think that overall, we had good teamwork. We helped each other when needed, and we efficiently completed the project. 

  In this investigation, I got to see what exactly osmosis and diffusion were like. I think it was a good experiment to help me understand about the processes that cells go through. I learned about osmosis through the cell membrane, and how it helps to transfer molecules. I also learned that with osmosis and passive transport, the cell membrane, depicted by the egg, works to keep the balance between the inside and outside. I found it interesting that, in the corn syrup investigation, the egg got smaller but then, after 2 days, it got larger again. I learned from this that the membrane works hard for the balance, until it is perfect or almost perfect. 

Concept Mapping: Cells

Why I, the Mitochondria, Should Remain on the Boat

Running, walking, standing, eating - even breathing - requires energy. The basic functions of our daily lives can only work with energy, energy that we get from the food that we eat. How does this relate to cells? Why should I, the mitochondria, remain in the cell? I am the power house, I provide energy for the cell to function. Without me, the cell would not be able to move, divide, breathe or survive. During the day time, chloroplasts can provide their jobs and create food for the cell. But what happens if there is nobody to convert that food into usable energy? That's when I come in, I take the food that the chloroplasts create and transform it into ATP, the energy that the cell uses to carry out basic life functions. Without me, the plant would surely die by lack of ATP which is made by cellular respiration in the cristae, folds in my inner membrane. That is why I should remain in the cell.

What kind of cell would I like to be and why?

Plant Cell and its Organelles

I would like to be a eukaryotic plant cell because even though my cell wall limits me from movement, I get maximum protection from the outside. Therefore, I am not as easily damaged as the other cells, Prokaryotic and Eukaryotic Animal, and can live a longer life. Also, I would have chloroplast which would create "food" that my mitochondria would alter transform into ATP, so that I can have energy to work right. This is the opposite for animal cells, which acquire their food from outside sources. Being able to "feed" itself to create its own energy, and having cell walls that protect and shape the plant cell, is an advantage over animal cells, which depend on many more factors to keep themselves working and healthy. Prokaryotic cells would also not be my first choice because even though they can be free moving with their flagella, they have no nucleus. It would be like a car without a driver. The nucleus is like the cell's "brain", and I would much more prefer having a brain than a car.