Introduction: Waves: Quirky Science (00:53)
In 1866, a dentist tried to make two wired kites communicate, which indirectly led to today's wireless communication. Find out how on this program.
Electromagnetism and Lodestones (01:54)
Wireless technology relies on electromagnetic waves. In a lodestone, one of the first magnets discovered, electrons can all point in the same direction, creating a charge attracting other objects.
Leyden Jar (02:21)
In the seventeenth century, a German scientist produced electricity. Leyden jars storing electricity were later invented; its workings are explained. Electricians used it to dazzle the European public.
Electricity is the flow of electrons that have broken loose from their atoms. The workings of electric shocks is explained, along with Franklin's kite experiment with lightning.
Discovering Relations Between Magnetism and Electricity (02:21)
Oersted found that electric current moved the needle of a nearby compass. Ampere discovered that change in current changes magnetic field. Maxwell made contributions.
Making Kites Communicate (01:37)
A nineteenth century American inventor created the first wireless aerial communication. He attached two kites separately to the ground and found that running current through one altered current in the other.
Hertz and Antenna. (01:27)
Hertz proved we can create electromagnetic waves; in the process of proving this point of theoretical interest, he invented the receiver or antenna.
Long-Distance Electronic Messages (02:43)
Many thought it was impossible to transmit electromagnetic waves over a long distance, as signals would choose their own path, but Marconi sent wireless telegrams across the sea.
Radio waves change as they encounter rivers, mountains, weather patterns and other phenomena; RADAR allows us to monitor these changes.
Electromagnetic waves serve many purposes because of the variety of their wavelengths. Wavelength is explained using water ripples as an illustration. Energy level of photons determines wavelength.
Working on the cathode ray generator, Rontgen accidentally discovered the x-ray. X-ray photons pass through a body, but not bones. Full-body scanners now allow us to see through clothes, generating images of naked bodies.
We are learning to read the waves we produce, as exemplified by MRI. Brain imaging may help us understand how people think. Electromagnetic waves' many uses are summarized and marvelled at.
Credits: Waves: Quirky Science (00:44)
Credits: Waves: Quirky Science
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