- pH can only have a value between 1 and 14.
pH is the negative log of Hydrogen ion concentration that we think can only be mathematically possible between 1 and 14. The truth is far from it, we only use the ‘normal’ pH scale of 1 to 14 for practical use because most solutions fall within it. But there are compound with negative pH as high as -35! pH is only the negative logarithm of H+ ion concentration. Don’t believe me? Calculate the pH of a solution of HCI with concentration of 10M. Spoiler alert, it’s -1. In fact, pH of any acid with concentration more than 1M is in negative.
2. Humans have 5 senses.
Humans have 5 sense? That said by Aristotle which has made its way into Junior School text books. Humans have more than the commonly cited five senses. The number of senses in various categorizations ranges from 5 to more than 20. In addition to sight, smell, taste, touch, and hearing, which were the senses identified by Aristotle, humans can sense balance and acceleration (equilibrioception), pain (nociception), body and limb position (proprioception or kinesthetic sense), and relative temperature (thermoception). Other senses sometimes identified are the sense of time, itching, pressure, hunger, thirst, fullness of the stomach, need to urinate, need to defecate, and blood carbon dioxide levels.
3. Thomas Edison invented light bulb.
Thomas Edison didn’t invent the Light bulb for the first time, there are about 22 people before him who worked upon development of the light bulb, but Thomas Edison might have invented the first ‘practical’ light bulb suitable for the market. Historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison’s version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve (by use of the Sprengel pump) and a high resistance that made power distribution from a centralized source economically viable.
4. Veins are blue.
Human blood in veins is not actually blue. In fact, blood is always red due to hemoglobin. Deoxygenated blood has a deep red color, and oxygenated blood has a light cherry-red colour. The misconception probably arises for two reasons: 1) Veins below the skin appear blue. This is due to a variety of reasons only weakly dependent on the colour of the blood, including subsurface scattering of light through the skin, and human colour perception. 2) Many diagrams use colours to show the difference between veins (usually shown in blue) and arteries (usually shown in red).
5. Evolution happens because of a characteristic need.
Evolution does not “plan” to improve an organism’s fitness to survive. For example, an incorrect way to describe giraffe evolution is to say that giraffe necks grew longer over time because they needed to reach tall trees. Evolution does not see a need and respond; it is instead a goalless process. A mutation resulting in longer necks would be more likely to benefit an animal in an area with tall trees than an area with short trees, and thus enhance the chance of the animal surviving to pass on its longer-necked genes. Tall trees could not cause the mutation nor would they cause a higher percentage of animals to be born with longer necks. In the giraffe example, the evolution of a long neck may equally well have been driven by sexual selection, proposing that the long necks evolved as a secondary sexual characteristic, giving males an advantage in “necking” contests over females. The misconception is encouraged as it is common shorthand for people who understand how evolution works to speak of a purpose as a concise form of expression (sometimes called the “metaphor of purpose”); it is less cumbersome to say “Dinosaurs may have evolved feathers for courtship” than “Feathers may have been selected for when they arose as they gave dinosaurs a selective advantage over their non-feathered peers”.