Knowledge N Fact4u

Why doesn't   a   laptop emit radiation ? •Your laptop computer does emit radiation. In fact, your laptop emits several different kinds of radiation: •400 to 800 THz electromagnetic radiation. This is the visible light given off by the laptop's screen that makes it possible for you to see what the computer is displaying. Yes, ordinary visible light is a form of radiation. •10 to 100 THz electromagnetic radiation. This is the infrared radiation given off by all parts of the laptop due to their temperature, through the everyday process of thermal emission. •5 GHz or 2.4 GHz electromagnetic radiation. These are the radio waves given off by the WIFI antenna in the laptop, which are used to connect to a wireless network. •2.4 GHz electromagnetic radiation. These are the radio waves given off by the Bluetooth antenna in the laptop, which are used to connect wirelessly to peripheral devices such as a cordless mouse. •Low frequency electromagnetic radiation. These...

How do trees give earth all its oxygen ? •All of earth's oxygen does not come from trees.  •Rather, the atmospheric oxygen that we depend on as humans comes predominantly from the ocean.  •According to a study, about 70% of the oxygen in the atmosphere comes from marine plants and plant-like organisms. •These ocean-living plants release molecular oxygen as a waste product of photosynthesis (as do most plants). •In photosynthesis, plants capture sunlight and use its energy to split carbon dioxide and water, making sugar for itself and releasing oxygen as a by-product. •The dominance of ocean life as earth's top oxygen producer makes sense when you consider that the majority of the earth is covered with ocean. •Of the different types of marine life providing oxygen, the dominant class is phytoplankton.  •Phytoplankton are microscopic photosynthesizing organisms that live in water.  •Phytoplankton includes cyanobacteria, green algae, diatoms, and dinoflagellate...

Clouds are just water vapor , so why do they move ? •Clouds are not water vapor. Water vapor is the gas state of H 2 O and is invisible.  •The air around you on a humid summer day is chock full of water vapor, but you don't see any of it.  •On the other hand, there is very little water vapor in the air during the cold of winter, yet you can easily make clouds with your breath.  •Clouds are collections of liquid water droplets or ice that are small enough to float.  •When the water vapor in the air gets cold enough, it condenses back into liquid in the forms of droplets.  •But the condensation is not automatic. It takes a bit of matter – a condensation nucleus – in order to jump start the process. Dust, salt, and ice in the air do the trick by providing a surface for the water to condense on to.  •Clouds are white because the water droplets making the cloud are the right size to scatter light resonantly according to Mie scattering.  •Mie scatte...

How do magnets heal ? •Magnets have no healing properties. Magnetic Resonance Imaging (MRI) employs very strong magnetic fields, far stronger than a household magnet can produce, and yet MRI's have no direct effect on the health of the patient (an MRI may have an indirect effect as a diagnostic tool). •The iron in our blood is in far too low of a concentration to be affected by the weak magnetic fields of household magnets.  •Furthermore, the iron atoms in our blood are bound in heme molecules. The chemical bonds that hold the iron atom in the heme molecule interfere with the state of its electrons, causing the iron atom to lose its usual ferromagnetic properties. •The lack of healing properties for magnets has been established multiple times through controlled experiments. •For instance, M.S. Cepeda and colleagues found that static magnetic fields had no effect on pain levels. •A study performed by M.H. Pittler reviewing multiple experiments also confirmed the in...