Ideal engines

In the first, we put the right side of the machine in hot water, and the left side of the machine in cool water; However the machine does not have any change because it is has a slowly reaction. Since, the hot water is changed to fire. When the one side of the machine is fired, other side of the machine still in the cool water, the machine starts to spin, and it becomes quicker and quicker. And we change it to one side in hot water, one side in ice, it still spins but slowly. Then we  plug in to electricity in the two sides, it spins quick as the first time. It tells us, the different temperature will change electrons' moving, and causes machine spin.

 In this lab, we use different mass to put in the top of the small pan and we connect it to a machine to measure pressure. we  performed a cycle by following the procedures and create graph of the P vs V diagram.

 The graph V vs. P

Each two connect point must have a relationship or in special state. Calculating the Q,W,U by given information. ()

Heat Engines

When a candle is putted into a long and deep tube the fire will go out. It because the burning fire is keeping using Oxygen, after Oxygen is burned completely, it goes out. Since after the fire completely all Oxygen in the tube, the fire goes off. However, if a along pipe is showed above the fire, the first will keep burning and never goes out because the pipe sends unburn gas out off the tube and out pressure pushes more Oxygen goes into tube. Taking out the pipe, the fire goes out.

 If a fire is pushed in a closed can and let it free fall, what will happen? The flame goes down because during the can is free falling, the few Oxygen moves up; however, there is not all Oxygen leaves down side, most of them are still on the down of can with fire. But the concentration of Oxygen decrease, and it effect the flame to be darker.

The experiment of work done by the change in volume and pressure. By the the formula W= ∫PdV and PV=nRT, the formula Q=P₁V₁ln(V₂/V₁) could be found. In the experiment, In the experiment, the temperature is constant, so the U (internal energy) does not change, Since the heat is added into system is equal to the work to change volume(W=Q)

Kinetic Theory and 1st Law

1. A unconstant volume can is putted in a hot water. by the time, the volume becomes bigger than the initial size. The reason for volume becomes bigger is when the temperature increases, the pressure increases, too.

(PV = nRT  → P = nRT / V) And the hot water transfers its energy into the can, and this energy push the volume to become bigger and bigger. Because the hot water is not that hot, the energy transfers is slowly, so the volume changes slowly, too.

Put in few cotton in a unconstant volume can. When the volume is changed very quick, the temperature will be changed very quick, too. By the calculating steps: 

CLASS NO.3

2.When a hot can was dropped into cool water, the can quickly shrunk.Because of the P = nRT / V, when n, R,V do not change but T, when T decreases quickly, the P decreases quickly. Since when the pressure of inside of can becomes smaller, but outside does not change, so outside of air pressure is more stronger than inside, then the can's volume becomes small quickly.

3.Test the pressure on U shape test tube: take few water  into U shape test tube, and mark water level, when one person blow either side of it, that side's water will go to under the level, other side's water is upward to the level. 

4.Experiment for finding relationship between Volume and Pressure.
                                              Temperature and Perssure
                                              Volume and Temperature

Experiment about the volume changing, when balloon and marshmallow are putted into a tool that could change pressure. When it starts to decrease the pressure, the balloon starts to become bigger. when it goes back to the normal pressure, the balloon backs to normal size. However, when the balloon is changed to marshmallow, when the pressure backs to the normal pressure, the pressure will become smaller than the initial size because its inside bubbles break when the pressure is decreased.

CLASS NO.2

1.The experiment of heating the bimetallic strip：
   When the bimetallic strip was heated, the brass expanded quicker than the invar.

The experiment of cooling the bimetallic strip：

  When the bimetallic was cooled, the brass shrunk quicker than the invar.

When the brass plate was heated, the hole became bigger. However in fact, the ring  expands in both side, its force push ring to be bigger.

2.Linear Thermal Expansion Demo
An one meter metal rod was clamped on one end, and it was heated by hot water. Measure △L.

4. Water and ice were mixed, using heater to heat them in a cup（Procedure ）.

The power of heater：299.2W

Graph：Temperature(℃) VS Time(s) （The graph is not very good because the initial point is not from origin. when ice and water are mixed, the temperature should be 0℃, but it is not.）

Calculating steps

Percent error

Calculating  uncertainty about the value, 0.5 was the smallest increment.

The uncertainty value cannot cover the our error in the experiment, because of operation and human error. When the ice and water are mixed, its temperature should be 0 ℃, but our initial value is not 0 ℃. And during the ice is transferring into cup, few ice has already became water, and it decreases the mass of ice. The last reason is there is not all energy to be used to heat water, but they are lost by heating air.

LAB 1 2 3

      1. First time the bubbles drop because they are fulled by CO2, p(CO2)=1.96g/L, it is  heavier than the density of the air. but when CH4 full the bubbles, p(CH4)=0.71g/L, its density is lighter than air, so it flies up. (Two different density of gas. The lighter gas, it is on the heavier gas, always rises up, and the heavier gas, it is on the lighter gas, always sink.)

And when we the bubble meets with fire, it will break. When the fire hits the bubble, bubble's kinetic energy gets growing up, when the too much kinetic energy in a bubble, until the bubble can not hold energy anymore. Then the energy is sheet out, and the fire is shot upward.

         2.When the 50g of cool water is filled into 100g of hot water, the energy transfer from hot to cool. Since, when the hot water loses energy, the temperature will drop down; however, the cool water gets energy from the hot water, so its temperature will rise up.(This energy is appeared by hot.)

The energy is transferred through cup's wall. Most energy can go through the wall from high energy to lower energy.

The way to increase the acceleration about water cooldown

3. Power about heater is 284.8W.

The relationship between the temperature(C°) and time(s) is a linear the T=mx+b; where m=0.3023C/s; b=20.16C; The physical meaning of the equation is

 T=0.3023C/s * t + 20.16

The relationship between the heat(q) and temperature(C°)  is a linear Q=mx+b; where m=4.7J/g/C; b=-94.65J/g; The physical meaning of the equation is q=4.7J/g/C * T - 94.65 initial. The slope of the between q and C is 4.7J/g/C is also named specific heat of water; however, this value has the 12.4% error compare to the true value of specific heat of water. That is because the heater does not be covered completely, and some energy is transferred into air immediately.