going to the next chapter

Before i start on the next chapter. hear some physics jokes:

Q: What did the thermometer say to a graduated cylinder.

A: You may have graduated but i still have more degrees than you.

Q: At a garage sale, a electron and a proton cost $10 each. How much does a neutron cost?

A: free oF charge ( no charge)

one day hydrogen said,"someone has stolen my electron! i am positive." then oxygen said,"Oh i thought you are just being negative again."

haha. funny. thats all

chapter 8- transfer of thermal energy.

basical this chapter is all about convection and conduction and radiation. the textbook is long winded again so i will summarise what i have learnt.

CONDUCTION

DEFINATION: Conduction is the process of thermal energy without any flow of the material medium.

Thermal energy is transferred from a region of higher temp. to a lower temp. but the time interval that it is transferred varies on the type of medium being used.

thermal energy is transferred faster in a good conductor (eg. wood) but slower in a poorer conductor( insulator).

this reminds me of a joke. one day a conductor lost his baton hence uses a sword to conduct. during practice, a player was constanly playing out of tune and the conductor got very angry and threw the sword at the player. he killed the player and was sentence to death through a electric chair but survived. the law states that if a man is not dead by the electric chair after 3 times of shocking, he can be released. and one day, the conductor lost his baton again and the same thing happen and still survived the electric chair. Why is this so? it is because he was a bad conductor.

haha funny.

CONVECTION

DEFINATION: Convection is the transfer of thermal energy by means of currents in a fluid

the arrows stated are the convection currents.

Hot air rises, cool air sinks

in this picture, the sun heats the air on the ground of the atmosphere, the hot air(red arrow) rises as air travels from a region of low pressure(hotter)to a region of high pressure(cooler).then the upper part of the atmosphere becomes cool and sinks. this is known as convection.

RADIATION

DEFINATION: Radiation is the continual emission of in farared waves from the surface of all bodies, transmitted without the aid of a medium.

i just went to youtube and found that handphones has high radiation and can cause cancer. i think i will use less of it now.

ALL COVERED!