6 wrong 'truths' in high school textbooks

The true number of senses, the magnetism of tomatoes and the basic colors are scientific knowledge that we often misunderstand or have not been taught properly at school.

Number of senses

According to Tech Times, the five senses such as taste, touch, sight, hearing and smell are not enough to feel the world. In fact, people perceive movements not only through sight, but also to recognize acceleration through the vestibular organ located in the ear. When moving, the air currents vibrate in small channels deep in our ears, allowing us to sense the change in movement speed, providing a sense of acceleration and balance.

5 common senses.(Photo: Scaa.org)

Similarly, when we stop breathing, we feel headache, dizziness, fatigue, and the brain stops working. This result is due to blood-soluble CO ₂ forming carbonic acid, which makes the blood pH lower than the permitted level. In addition, humans have many other senses that allow us to feel what is happening inside our body as well as our surroundings, such as temperature, pain, space - time.

Adverse words

Among the three options are tomato fruit, paper pin and human, we often assume that only magnetic paper pins. In fact, we were mistaken because both tomatoes and humans are magnetic.

A reverse magnetic material hovering over a magnet.(Photo: Theodoregray.com)

Paper clips contain magnetic materials such as iron, cobalt and nickel, meaning they can be attracted by magnetic fields. There is water in the body and the tomato. More specifically, there are hydrogen nuclei in the body and tomato fruit, which can be repelled by magnetic fields . This interaction is called diamagnetism.

The magnetic forces of hydrogen atoms are extremely weak, so we pay little attention to the effect of magnetic fields on the body. When we are in magnetic resonance imaging (MRI), a giant magnet interacts with different atomic nuclei inside our bodies and creates an image that carries detailed information about internal activity. body.

Basic colors

In school, we are taught that basic colors are colors that cannot be created by mixing different colors. All other colors can be created by blending the base color according to a certain formula. But this is not true, at least in red and blue.

Three basic colors.(Photo: Wikipedia)

We can create red by mixing yellow with magenta (magenta). Blending bright red with cyan (cyan) will create blue. Meanwhile, many colors cannot be created if we start with only red, blue and yellow.

Scientists have discovered this fact since the end of the 19th century, but for some reason, this knowledge was not included in the curriculum at schools. Evidence is in the color printer cartridges that we often use, only three basic colors are cyan (cyan), yellow and magenta (magenta). Those are really basic colors.

Taste area

In the map of the taste area in the biological textbook, the feelings of bitterness, sweetness, and sour taste form in separate positions. In fact, scientists have shown that there is no difference in the perception of different tastes at different positions on the tongue.

Four positions 1, 2, 3 and 4 are practically no different in taste function.(Photo: Messer Woland)

Taste map appeared for the first time in 1942 after Edwin Boring at Harvard University, USA, published the study mistakenly on this issue. However, the taste map contains many errors of Boring soon appeared in the general curriculum. Then, in 1974, this topic was reviewed by scientists and all of Boring's research results on the taste map were denied. However, more than 40 years later, confusion about the taste map still exists in many biological textbooks.

Material state

We all know that solid- state matter has a constant shape because its molecules are tightly bound in a certain order. When melted, these materials turn into liquid with constant volume. Volatile liquid will form gas with a volume that expands the entire container. Those are the three physical states we learn.

Liquid crystal.(Photo: Wikipedia)

In fact, matter exists in other states. For example, liquid crystals with molecules are arranged as solid state but in liquid form. Liquid crystals are necessary for cell activity, existing in shampoos and liquid crystal displays (LCDs).

In addition to liquid crystals, matter can also exist in plasma form, the state of almost every material on the Sun. The scientists also found Bose-Einstein condensate, superfluid state and dozens of other physical states.

Negative refractive index

We all learn about light refraction in a universal physics program. Light rays (electromagnetic waves) that pass through the interface between two refracted environments, refracting rays are located in the other half of the normal than the incident rays. The angle of refraction created with the normal is characterized by the refractive index of the refractive medium and this value is always positive.

Illustrate refraction in liquids with negative refractive index (left) and normal water (right).(Photo: Cfn.kit.edu)

Nearly half a century ago, Russian theoretical physicist Veselago proved that mathematically, the refractive index of an environment can receive negative values . However, for many years thereafter, scientists did not find any material in nature with a negative refractive index.

Until the beginning of the 21st century, an artificial material made of resonant circuits smaller than the wavelength of light allowed observations of negative refractive index to be observed, as predicted by Veselago. Once these negative refractive materials are made in the proper form, they will give strange optical refraction images that we have never experienced.