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Friday, December 11, 2009
Thursday, December 10, 2009
Tuesday, December 8, 2009
Convection
Convection is heat that is transferred through air currents and can happen in liquids or gases. Hot air has much faster atoms that are further apart then colder air. In addition, hot air is less dense than the much heavier cold air surrounding it. So the cold air falls down, pushing the hot air back up. This produces a convection current. An example of convection is when you turn on your heater or furnace. The furnace takes the air from outside and heats it up, and when its heated it spreads the air throughout the vents in the house. Once through the vents, the air spreads throughout the house, making it warm.
Monday, December 7, 2009
Atoms and Molecules
Atoms and molecules are the building blocks of all matter. Multiple atoms together come to form a molecule. An example of a molecule is sugar and citric acid, which is known as orange juice.
Atoms and molecules are part of heat because the atoms are always moving and the movement creates the heat. As atoms get hotter, they move more faster and more uncontrollably. The hotter atoms collide with they much colder and slower atoms, making them as hot too. An example of this situation is when your spoon touches your hot soup. The much faster moving atoms inside the soup collide with the much slower moving atoms, making them hot as well. Another example of such happen when you leave ice cream out in the open for it to melt. The ice cream has very slow atoms but when it becomes more heated than the atoms slowly get faster.
Atoms and molecules in a solid, liquid, gas, or plasma states have either low or high density rates.
Atoms in a solid are tightly packed together and are not free to move around as much. Solids have a definite shape and definite volume. In liquids, however, the atoms are allowed to move freely and the atoms are less packed as they are in a solid. Liquids have no definite shape and they take the form of the container they are in. Liquids also have a definite volume. In gases and plasmas, the molecules much farther apart then solids and liquids. These two states of matter don't have a definite volume or shape and are able to move around freely in unquestionable amount of space.
Thursday, December 3, 2009
Radiation
Radiation is heat that is transferred by the heat waves that travel through empty space. Some examples of radiation is the sun because it creates heat on the earth and it also creates light that is known as sunlight. Another example of radiation is when you us a your fireplace or when you go camping and you make smores over a fire. Some more cool examples are the radiation from a microwave cooking oatmeal, another is the light from a lava lamp, and lastly is the steam from a piping hot tea.
Conduction
Conduction is heat that is transferred through when molecules of different temperatures rub or touch each other. Conduction comes in the form of direct heat. When conduction is happening, the hotter atoms start to move faster, making their neighbors hot too. Some materials such as metal are much quicker in heating up then others. Good carriers of heat are called conductors while others are called insulators. An example of when conduction happens is when your hands are touching the handles of a pan when you are cooking food. The heat from the stove goes to the pan, and metal is a good conductor of heat, the heat energy goes through the pan and into your hands! When you are cooking soup or eggs, the heat goes through the pan to the food so the food gets cooked for you to eat. Another example of conduction is when you are holding ice in your hand and it melts after a while. Since your body temperature is hotter than the ice, the faster moving atoms in your hands bump the slower ones in the ice, slowly heating the ice up so it melts.
Tuesday, December 1, 2009
Conduction, Convection, and Radiation
The three types of heat transfers that are occurring around us are conduction, convection, and radiation. If you take a vacation in the beaches of Hawaii, and when your feet touch the hot sand, your feet get hot. This is called conduction because the heat is transferred through one thing to the other. It is radiation when you are at the beach and you get sunburned.It is radiation because the sun is transferring heat in the form heat waves. An example of convection is when you are cooking food above the stove. The steam is hot so it rises up to the pan to heat the food. Convection is when heat is transferred through air currents.
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