Electric sparks simulate lightning from a 400kV Tesla machine. With high frequency, it can also light up fluorescent lamps at a distance of up to 3m, illustrating the principle of transmitting energy without wires.

- When electric current passes through the coil, the pointed tip will begin to discharge electricity and sparks will appear shaped like lightning bolts.

Explanation:

- This device is called a Tesla Coil. This device was invented by Nikola Tesla in 1891, and can create very high voltage (from 50 kV up to several million volts) with low current intensity and high frequency.

- High voltage will ionize the air near the electrode, making this air area conductive and forming electric sparks. The phenomenon of lightning in nature is also formed with a similar mechanism.

More information:

- Nikola Tesla (July 10, 1856 – January 7, 1943) was a Serbian-American inventor, electrical engineer, and mechanical engineer. He is best known for his contributions to the modern alternating current power supply system.

Applications in life:

- X-rays, remote control radio waves, wireless charging technology on phones, tablets,...

Electric sparks simulate lightning from a 400kV Tesla machine. With high frequency, it can also light up fluorescent lamps at a distance of up to 3m, illustrating the principle of transmitting energy without wires.

- When electric current passes through the coil, the pointed tip will begin to discharge electricity and sparks will appear shaped like lightning bolts.

Explanation:

- This device is called a Tesla Coil. This device was invented by Nikola Tesla in 1891, and can create very high voltage (from 50 kV up to several million volts) with low current intensity and high frequency.

- High voltage will ionize the air near the electrode, making this air area conductive and forming electric sparks. The phenomenon of lightning in nature is also formed with a similar mechanism.

More information:

- Nikola Tesla (July 10, 1856 – January 7, 1943) was a Serbian-American inventor, electrical engineer, and mechanical engineer. He is best known for his contributions to the modern alternating current power supply system.

Applications in life:

- X-rays, remote control radio waves, wireless charging technology on phones, tablets,...

Two very different Mona Lisa images are presented in reverse. Very difficult to notice the difference, but when the player rotates the two pictures the difference becomes clear. That's because when rotating images, the brain can use existing concepts about faces to as a reference point.

- This is a strange visual psychological effect called the "Thatcher illusion" or "Thatcher effect".

This effect was discovered by Peter Thompson - a British cognitive scientist - in

1980. The first photo he created this illusion was of Margaret Thatcher - prime minister

He was at that time.

- The human brain often recognizes faces in block form: eyes, nose, mouth... and then sums

combined to form a face. When rotating the image upside down, the eyes and brain still recognize details well, automatically

rotate the blocks upside down and combine them into a complete face without noticing the difference

until the face is turned in the right direction.

- The interesting thing is that even though we know about this effect very well, the brain is still very

so "confident" that when we glance at two pictures, we will still feel that they are no different at all.

Practical applications:

- Knowing that the human brain recognizes a face by remembering the characteristics of the sets

individual parts: eyes, nose, mouth... and then put them together, artists can express

my photos of people are more realistic and effective; Besides, human identification work

Investigating and solving crimes has also become more convenient.

- Supports the treatment of patients with autism syndrome and facial recognition disorder syndrome.

- The Ames Room is a room distorted to deceive the human eye. Possibly influenced by the writings of Hermann Helmholtz, it was invented by ophthalmologist Adelbert Ames, Jr. in 1946, and was built the following year. - The Ames room was viewed with one eye through a pinhole to avoid any suspicion from cubic vision, and it was constructed so that from the front it appeared to be a normal cubic room, with one back wall and two side walls parallel to each other and horizontally perpendicular to the floor and ceiling. However, this is just a trick of perspective and the true shape of the room is trapezoidal: the walls are slanted and the ceiling and floor are slanted, and the right corner is closer to the front observer than the left corner (or vice versa). - As a result, a person standing in one corner is a giant, while a person standing in another corner appears to be a dwarf. The illusion is so convincing that a person walking back and forth from the left corner to the right corner appears to grow larger or smaller. Studies have shown that illusions can be created without the use of walls and ceilings; it is enough to create an apparent horizon (which in reality will not be horizontal) against a suitable background, and the eye relies on the apparent relative height of an object above that horizon.< /p>