Top 8 Questions About Human Body Reactions Kids Often Ask and How to Answer Them Scientifically

Explain to your child: This phenomenon usually occurs when the body is suddenly exposed to cold temperatures. The muscle contraction helps to maintain body temperature and prevents cold from entering. It is also a sign of homeostasis, the body's internal balance system, which regulates the environment inside to keep everything in equilibrium, adjusting mechanisms to stabilize organ functions and maintain body temperature.

Things to know: Shivering is the body’s response when the temperature changes quickly or becomes too cold. However, it's not just a reaction to cold environments; shivering can also be a symptom of an underlying condition that requires treatment. Many factors can cause shivering. When the temperature drops below a certain level, you may begin to feel cold and shiver. Shivering helps warm the body to adapt to external temperatures. It can continue for hours, but after a while, muscles run out of glucose (sugar) for fuel, causing them to tire and stop contracting. Each person experiences shivering at different temperatures, such as children, who lack a lot of fat under the skin and may start shivering at higher temperatures than adults. Sensitivity to cold also changes with age or health concerns. For example, those with hypothyroidism may feel colder than others. Wind or wet clothes can also cause people to feel colder and trigger shivering.

Explain to your child: Many people think yawning is just a sign of tiredness or boredom, but scientists believe yawning could be the brain's way of cooling down. Essentially, it works like an air conditioning system for the brain, helping you stay alert when you're stressed. Interestingly, when you see someone else yawn, you might find yourself yawning too.

Things to know: Yawning is a natural physiological response that cools the brain and can also express emotions in communication. Sometimes, yawning can be a sign of certain health conditions. It's an involuntary reflex, involving a deep inhalation, mouth opening wide, and air entering the lungs. This causes the eardrums to stretch, your eyes to close tightly, and often tears to form. Yawning is a function of breathing, especially when the body needs more oxygen. A single yawn pulls in a large amount of air, which causes the heart to beat faster. The extended jaw increases blood flow to the face and neck. When taking in such a large volume of air, the blood and cerebrospinal fluid circulate faster, helping to cool the brain.

Explain to your child: Hiccups happen when the diaphragm and intercostal muscles contract involuntarily and repeatedly. When a trigger causes the diaphragm to contract, air rushes into the throat, striking the vocal cords. This sudden closure of the vocal cords results in the familiar 'hic' sound.

Things you should know: Breathing involves the diaphragm, a muscle that helps pull air into the lungs and release it. Hiccups can occur if you eat or drink too quickly, go too long without eating, drink cold liquids while eating hot food, consume spicy or highly seasoned foods, laugh loudly, cough, drink excessive alcohol, or cry. These actions can force air into the abdomen and get trapped in the throat, causing the diaphragm to react and produce hiccups. If the hiccups last only a few minutes or within one day, there is no cause for concern. However, if they last more than 24 hours, it may be a sign of an underlying condition, and you should see a doctor for evaluation.

Explain to your child: Blushing typically happens when you're embarrassed, shy, or scared, or when there are issues with your blood pressure or heart rate. Biologically, this occurs when blood vessels in the face expand, allowing more blood to flow to your cheeks, creating a red or pink tint. However, scientists haven't yet confirmed the exact purpose or benefit of this response.

Things you should know: When you're in an emotional state, like feeling embarrassed after bumping into someone's coffee or nervous from catching the gaze of someone attractive, your body releases adrenaline. This hormone causes blood vessels to dilate, allowing blood and oxygen to circulate more efficiently through the body. As a result, not just your cheeks but also your ears, neck, and chest can turn red. Everyone experiences blushing differently—some people turn red quickly, while others might see the redness spread more slowly. Some individuals blush more easily than others, and there are cases of people suffering from erythrophobia, a fear of blushing.

Explain to your child: Drooling happens because it's a natural way to lubricate the mouth, help digest food, and protect the mouth and teeth before vomiting. It can also occur when you think about or look at appetizing food, particularly sour dishes. Additionally, drooling can be a sign of hunger.

Things you should know: There are several reasons for excessive drooling in both children and adults, such as disorders affecting the salivary glands, foods that stimulate saliva production like spicy foods, or having a large and late dinner. People who experience stress, anxiety, or have habits like teeth grinding at night may also drool more. Conditions like stomach or esophageal ulcers, or a habit of eating sour foods like lemons, oranges, grapefruits, or tamarinds, can trigger drooling as well. To reduce drooling, it's helpful to explain to your child the importance of avoiding spicy foods, chewing gum, or having large late meals, as well as managing stress from school or family-related pressures.

Explain to your child: Crying often happens due to sadness, but it is a complex human response. You may cry because of pain, disappointment, or even from overwhelming joy. Whether you're crying or laughing, it's all a positive response from your body. So, if you laugh so hard that you cry, consider it a sign of good luck.

Things you should know: According to Fox, experts still don't have a full explanation for this, but one thing is clear: both laughter and crying are emotional reactions. They often occur when we're hit with intense emotional stimuli. As Robert R. Provine, a psychologist at the University of Maryland, Baltimore County, explains, both are triggered by strong emotional experiences. A study soon to be published in the journal Psychological Science by a group of psychologists from Yale University suggests that crying when happy helps our body balance its emotions. Responding to intense positive emotions with a negative expression might help us recover better from such powerful feelings.

Tell the child: When chopping onions, we break the onion's epidermal cells, releasing enzymes that produce a gas called propanethial sulfoxide. When this gas reaches the eyes, it reacts with the tear fluid to form a mild sulfuric acid, causing the stinging sensation. The brain then sends signals to the tear glands to produce more tears to wash away the irritant.

What you need to know: According to scientists, when onions are chopped, their cells release a compound called sulfenic acid. This acid combines with an enzyme called alliinase to create a gas known as propanethiol S-oxide. This gas reacts with the moisture in the eyes, forming sulfuric acid, which irritates the eyes. The nervous system treats this as a stimulus and directs the tear glands to produce more tears to flush out the irritant. This 'crying gas' acts as a defense mechanism for the onion, protecting it from bacteria and animals that could harm it, including humans. The damage to the onion triggers a unique chemical reaction to protect it. 'However, if either of the two is destroyed, they will meet and create a reaction,' explained Marcin Golczak, a biochemist at Case Western Reserve University.

Tell the child: Goosebumps are a bodily reaction that occurs when you feel fear, cold, or hear a special piece of music, even when you hear the squeaking sound of two objects rubbing together. However, there is no biological reason explaining this strange phenomenon, and it doesn't have any health benefits. Goosebumps are a trait inherited from our ancestors. Similar to animals with fur, they often raise their hair in response to stimuli or to retain body heat. Due to evolutionary changes, humans have less hair, so we can observe the reaction through the raised pores, which serve as a substitute for the fur.

What you need to know: Goosebumps, also known as 'chicken skin' or 'piloerection,' is a natural reflex of the body. This phenomenon typically occurs in response to cold or intense emotions such as fear, surprise, anger, or excitement. In this case, the skin forms small raised bumps due to the contraction of the muscles attached to each hair follicle. The hair deeply embedded in the skin is surrounded by a sac (follicle), and each sac is connected to a muscle that causes the follicle to swell, making the bumps appear on the surface of the skin. This is what we call 'goosebumps.' When the sac swells, the hair inside stands up. Goosebumps are most noticeable on the arms, legs, and neck, but they can even appear on the face. They usually disappear once the stimulating factors subside.