firewalking and greenhouse effect
how to calculate calories in peanut
how to a lake freezes over
thermodynamics
evaporation vs. condensation
100
What is firewalking?
Firewalking are people who walk barefoot without harm over red-hot coals from firewood.
100
How much does 1,000 calories equal?
1,000 calories equals 1 kilocalorie or 1 Calorie
100
What unique property does water have?
It's unique property is expanding. When it freezes it expands and becomes a solid. Because water expands when freezing, plants and animals can live in the water all winter.
100
What is the first law of thermodynamics?
The first law of thermodynamics is heat added to a system is transformed to an equal amount of some other form of energy.
100
What is evaporation?
Evaporation is the change of phase from liquid to gas that takes place at the surface of the liquid.
200
When do firewalkers get burned?
Firewalkers get burned when the conditions are not good.
200
Why shouldn't you boil water too much?
You shouldn't boil the water too much because the water will evaporate in the air and lose energy.
200
What is the boiling point and freezing point of water?
boiling water: 212 degrees F (100 degrees C) freezing point: 32 degrees F (0 degrees C)
200
What is the second law of thermodynamics?
The second law of thermodynamics is heat will never of itself flow from one object to another of higher temperature.
200
What is condensation?
Condensation is the change of phase of a gas into a liquid.
300
What is the greenhouse effect?
The greenhouse effect is the warming effect whose cause is that short-wavelength radiant energy from the sun can enter the atmosphere and be absorbed by Earth more easily than long-wavelength energy from Earth can leave.
300
What is the equation to finding the amount of calories something has?
The equation is temperature change times mass of water equal calories.
300
Why can some lakes be strong enough to support the weight of ice skaters and sometimes cars?
Some lakes are strong enough because the conduction in the air takes more heat energy than it gets from the top surface, so the layer becomes thicker. Eventually, this thick layer of ice is strong enough to support ice skaters and cars.
300
What is an example of the First Law of Thermodynamics?
Examples of the First Law of Thermodynamics are helium boiling or if there is gas confined by a piston in a cylinder. If the gas is heated, it will expand, doing work on the piston.
300
What happens when the human body overheats?
When the human body overheats, our sweat glands produce perspiration. Evaporation of the perspiration cools us and helps us keep a stable body temperature.
400
Why is it important to know about the greenhouse effect?
It is important to know about the greenhouse effect because it gives off enough heat to keep out planet warm. Without it our planet would be too cold for things to be living on it.
400
Why do you used food as fuel for your body?
You use food to fuel your body because food contains stored energy that helps you to move, talk, eat, etc. Food keeps you alive because it keeps your body process going.
400
Why is the turning over of a lake good for plants and animals in the lake?
It's good for plants and animals because everytime the lake turns over, it takes oxygen from the top to the bottom. The dissolved nutrients from the bottom are brought to the top. So the lake is oxygenated for the winter when the top is sealed by ice, and nutrients are mixed together.
400
What is an example of the Second Law of Thermodynamics?
An example of the Second Law of Thermodynamics are in an ocean there is a huge amount of internal energy, but all the energy cannot be used to light a single flash light lamp without external effort. Energy will not of itself flow from lower temperature ocean to a higher temperature of a lamp.
400
What is happening to the outside of a cold can of soda?
On the outside of a cold soda can there are formation of droplets of water that form. Water vapor molecules collide with the slower-moving molecules of the can. Since the vapor molecules give off lots of kinetic energy, they can't stay in a gaseous state, so they condense.
500
What are two factors in firewalking?
The two factors in firewalking is 1) the low conductivity of wood. Even though it has a high temperature there is little heat that is conducted to the feet. 2) skin moisture. Perspiration on the soles of you feet decrease heat transfer to the feet. Most of the heat that would go the the feet goes to vaporizing the moisture instead?
500
How do you calculate the amount of calories a peanut has?
You can calculate the amount of calories by burning the food. When you do that the heat energy can be absorbed by a mass of water. You first get a peanut and weigh it. You then light it on fire with a match under a mass of water. Once the fire goes out, measure the temperature change. Then you can used the equation (temperature change x mass of water = calories.)
500
What is the process of a lake "turning over?"
Cold water on the surface of the lake will sink until the water temperature drops to below 4° when the water is most dense. Below this temperature, water is less dense because of microscopic slush crystals. Water cooler than 4° floats to the top where it cools to 0° and freezes. The freezing changes all the water into crystalline state which is less dense than water in a liquid state, so solid ice will go to the top.
500
What does the field of thermodynamics study? What does the law of thermodynamics describe?
The field of thermodynamics studies the behavior of energy flow in natural systems. The laws of thermodynamics describe the fundamental truths of thermodynamics observed in our Universe.
500
What are three differences between evaporation and condensation?
The three differences are 1) evaporation is the change from liquid to gas while in condensation is the change from gas to liquid. 2) evaporation is a cooling process while condensation is a warming process. 3)In evaporation in the liquid phase there are only one type of molecules that bump each other, but in condensation there are fast water vapor molecules bumping into slow-moving molecules.
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