chemteam rocks: Oct. 29-31, Nov. 1-2

This week, I have learned about the relationship between Kelvin and Celsius, how pressure and temperature affect the motion of particles, how low and high-pressure systems are caused, and reviewed last week's material for this week's assessment.

This week, we learned about pressure affecting the motion of a syringe needle using 2-liter bottle filled with water–one with a syringe needle in a closed system and the other in an open system.

I learned that as we squeezed the pop bottles, the syringe needles went down because the volume decreased, accounting for the increased pressure. So, these two factors caused the force to go upward. As the force reached to the top, there was even less volume to go up, since the syringe needle provided some resistance, so the force went downward since it was exerted onto the syringe needle.

But, since one was in a closed system and the other was in an open system, the one in the closed system went down easier since nothing went into the syringe needle and resisted the downward motion. However, in the open system, there was upward resistance in the syringe needle since some water got into it, but it wasn't enough to prevent the downward force since it had greater pressure than the upward resistance, thus causing the syringe needle to go down, but not as quickly.

This week, I also learned how the temperature affects the motion of particles in glow sticks. My group and I experimented with the different temperatures of water and put the glow sticks in the water. We found that the relationship between the brightness of the glow sticks and the temperature is that as the temperature increased, the brightness increased because the temperature increased the motion of particles and their traveled distances. However, the glow sticks in the cooler water didn't glow as much because the particles were more closer together, didn't move as quickly, and didn't move greater distances. Therefore, the temperature of the water affected the brightness of the glow sticks.

Understanding that particles have motion, I also speculated that there was a point where there wasn't any motion at all. I learned that Absolute Zero is the point where particle motion stops because at Absolute Zero, there is neither any energy input, nor is there any pressure.

The mathematical equation for Absolute Zero is:

Pressure=(pressure/Celsius)(Absolute Zero in Celsius)+(pressure when T=0ºC)

These are the steps to find Absolute Zero in this example:

Absolute Zero is -273.15ºC, or 0(K).

To convert Kelvin to Celsius:

kelvin = degree Celsius + 273.15

To convert Celsius to Kelvin:

degree Celsius = kelvin - 273.15

For the weekend, I am working on a barometer for a chemistry assignment. So in class, I learned that a barometer is an instrument that measures atmospheric pressure, and the liquid inside of it expands or contracts based on the pressure it measures. Although somewhat similar to a barometer because they are both instruments of atmospheric pressure, a manometer is an instrument that measures difference in pressure from atmosphere to system of gas, in contrast to measuring atmospheric pressure itself.

This week, Sandy was the major topic everywhere–on TV, in the news, in my journalism class–even in chemistry. Although it didn't cause the most damage, it was considered to be one of the worst hurricanes in history since it had the greatest air pressure. Since hurricanes occur in low-pressure systems, this caused hurricane Sandy to expand. A low-pressure system is caused by greater heat in the air, decreasing its density, causing it to rise and lowering atmospheric pressure downward toward the Earth's surface. As the pressure lessens, the moisture increases. The heat then causes storms to occur by causing the liquid water to condense, thus explaining why hurricanes move from the Gulf of Mexico to the coast.

However, in a high-pressure system, a hurricane would contract since pressure acts upon the hurricane and resists it. In a high-pressure system, a great deal of pressure is pushing down on the Earth's atmosphere, thus discouraging the formation of storms and hurricanes, since cold air is more dense than warm air; causing the warm air to go downward while the cold pushes down upon it. That's why it's bright and sunny in a high-pressure system.

Kinetic Molecular Theory is the overall theory that supports what we learned in class about particles, states of matter, energy and motion, temperature, volume, and pressure. Particles are always in motion, particles in liquid collide with container, change in energy affects motion, all states of matter involve particle motion, matter exists in three states of matter, increasing temperature increases particle motion, and volume and pressure have an inverse relationship.

Review from last week: