What will happen to metal containers that are filled with liquid or gas at high pressure if they are exposed to extreme cold or to a temperature above 120 degrees celcius? Why so?
Are containers filled with liquid or gas at high pressure, thermostats and thermometers influenced or affected by the effects of heat?
What effects cause the density of the air in a hot air balloon to change?
What is the name of the gas that bubbles in the dough to make the dough rise?
Mercury and alcohol are usually used in liquid-in-glass thermometers. Suggest why these liquids, instead of water, are used.
How is heat transferred between the polar bear and it's surroundings?
Both mercury and water are liquids at room temperature. Why is mercury a good conductor of heat, but not water?
What is a souldering iron used for? A souldering iron has an iron rod with a copper tip. Why is the tip made out of copper instead of iron?
Can heat be transferred by convection in solids? Why/why not
2007-10-05 20:46:57 · 3 answers · asked by Yuppy kid! =P Roxzzz.... 2 in Science & Mathematics ➔ Physics
Pple this isn't my homework. I came across these questions when i was going through some of the chapters and if go to my profile you will see that i have tons of those questions cause my science end-of-year exam is on this tuesday which is why i am not googling all this!!! I don't have all the time in the world so plzzz help me!!! help would be GREATLY appreciated!
2007-10-05 20:56:48 · update #1
At high temperature, container can explode if the liquid crosses its boiling point at that pressure. At very low temperature, liquid like water may freeze to ice and as ice has low density, it occupies higher volme as compared to liquid water which can also explode the container or deshape it such that its volume is more. Maximum volume is that of a sphere. Every liquid on solidifiaction do not expand.
In hot air balloon, fuel burnt results in a lot of carbon dioxie and also steam. Bothe these gases have high density and that increases the density of air near the balloon and thereby increases the force of bouyancy.
Gas that causes dough to rise is steam.
Because, mercury and alcohol have higher linear coefiicient of expansion. So, they expand to a greater extent with rise of temperature. This property of mercury and alcohol make them more suitable for use in thermometers.
Heat is transferred mainly by conduction between polar bear and its surroundings.
Mercury expands to a greater extent due to same rise of temperature which increases the rate of heat transfer by convection of mercury atoms much more than the molecules of water. Decrease in density of hot mercury atoms is much higher than the decrease in density of water molecules for the same rise of temperature which is the reason for higher rate of heat transfer by higher rate of convection. Moreover, Mercury is metal and has free electrons which make it better conductor of heat. Heat is conducted by convection by electrons also.
Soldering iron is used for joining two electric wires with continuous elctric connection. Copper at the tip melts and solidifies on the two wires joining them for good electric contact.
Heat is transferred by convection in some solids like metals to a limited extent by the free electrons in metals. Non-metals do not have these free electrons and hence are nonconductive for heat.
2007-10-05 21:17:54 · answer #1 · answered by Madhukar 7 · 1⤊ 0⤋
Too many questions in one question. I will answer one or two. Post separately for better responses,.
Both mercury and water are liquids at room temperature. Why is mercury a good conductor of heat, but not water?
Mercury is a metal and metals are in general good conductors compared to non-conductors (like water). Metals have free electrons which carry electrical charge and heat etc.
Can heat be transferred by convection in solids?
No. Convection involves physical movement of atoms and molecules and solids are solids because the forces between atoms in solid are strong. Liquids and gases support convection. Heat is transferred by conduction in solids.
2007-10-05 20:58:36 · answer #2 · answered by Swamy 7 · 1⤊ 0⤋
The name of the gas is carbon dioxide. Zymase catalyses the breakdown of glucose into ethanol and carbon dioxide.
Density is mass/volume right? Volume can change by pressure (Boyle's Law) and temperature (Charles' Law).
Water sticks to the surface of the capillary tube. It also has a high melting point and low boiling point. Mercury and alcohol has very low melting points... so they are very good thermometers.
Is it "soldering iron"? If so, it's used for welding...
Transfer of heat in solids by conduction.... either that... or my physics need reading.
2007-10-05 21:12:32 · answer #3 · answered by Sammuelz_101 1 · 1⤊ 0⤋