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.
