health / Hearts / life science

I Heart Valentine’s Day

We often try to discuss science topics that are associated with the season or a holiday. This month there is no shortage of hearts as we approach Valentine’s Day. Heart shaped candies, candy boxes, cards, and even clothing accessories abound on store shelves and your child can not escape noticing these as you run errands.


So if you think your child is interested, why not turn the discussion to the real thing, or our hearts and their function? Understanding our bodies is essential for understanding the concept of health and for the life sciences more generally.

In introducing an exploration of the heart, as with any of the topics on this blog, don’t hesitate to also incorporate stories, poetry or art. Valentine’s Day is about the heart. Not the one that pumps blood, but the one that loves, or can be broken if that love is not returned. The heart-shaped symbol we are all familiar with is called an ideograph – something that represents the metaphorical or symbolic sense that the heart is the center of emotion. Themes of love are common in children’s stories and thus familiar, but the emotion of love will take time, even a lifetime, to comprehend. So explore the two “hearts,” both the organ and the symbolic source of emotions, as they deserve deep inquiry to promote appreciation and understanding.




Where is my heart?


What does it look like?


What does it do?


Do all hearts in animals look alike?




Can a heart be broken or mended?


Why do we talk about love and think of a heart?




Can a heart get sick?


What makes a heart go, or keep pumping?


Where does the blood go that the heart pumps? (Everywhere in the body!)




Ask your child where her heart is. If this is the first time she has pondered this question, you can show her. You can also find illustrations of the heart and other organs in the body as a start, but you do not want to overwhelm with too much information. One interesting point to emphasize is that you and your child can still discuss and learn about things that you cannot see. The heart is a great example of this concept!




Have your child place her hand over her heart to see if she can feel it beating. Invite her to feel your heartbeat, a sibling’s or a pet’s. Help her find the language to describe what she is feeling.


Perhaps now is a good time to suggest that the heart is a special muscle in the body. Are there other muscles in the body? Where are they? How can you tell, or what about how they feel tells you it’s a muscle? (Hint: The heart is an involuntary muscle meaning it works all on its own. We cannot start or stop it. Other muscles can be relaxed or put into action. Invite your child to think of a muscle and flex it. Now think of her heart. Can she control its beating? Yes, to some extent she can speed it up, but otherwise, it is doing its own thing).


What else is she feeling in the area around the heart? Could there be a rib or two? What function might these serve? (They protect the heart)




Feel the work of the heart by finding a pulse, yours or your child’s, and have her feel that. Pulses can be detected on a wrist or the neck, or, if you are lucky, you can even find one around an ankle. Invite your child to see if he can find all of these points where a pulse can be detected.


Pulses are key to what the heart does or pumps blood throughout the body. Find language to describe what is felt, but also, consider drawing dots, lines or dashes as an alternative way of characterizing the observation. (Can you draw the pulse you are feeling?)


Listen to a heart. If you have access to a stethoscope this is the best way to hear the heart working away. Next time you visit a health professional ask if she will let your child listen to his heart with this medical and scientific instrument. If you do not have a stethoscope, you may still be able to amplify the sound by holding a paper cup or cardboard tube over a heart and placing an ear on the other end. If you are more of a hands-on type there are a couple links to making homemade stethoscopes in the experiment section.




Give it a try, or experiment with other items that may help channel the sound of a heart so that it can be heard. What sound does he hear? Have him try to replicate the sound. Listen to other people’s hearts. Does he hear the same sound?


If you don’t have a stethoscope or the cup is not working, here are websites that will allow one to see and hear the heart pumping away. These might be a little advanced, but hey, let your child give them a look and listen and if he’s interested, then no harm done.








Ask what your child is observing (sees and hears). Healthy hearts make an identifiable sound or lub DUB lub DUB. The heart is a muscle pumping blood out into the body, but that blood is circulating, so it must also enter the heart before leaving it again. Entering and leaving is the result of opening and closing valves as the heart expands and contracts (these are the sounds you hear). If observing a video, ask what the heart is doing and how it is doing it? That is, is the heart’s function or mechanisms clear (to pump blood throughout the body)? If not, perhaps find other illustrations to talk about the heart and its role in providing blood to the rest of the body.


Here is an example of an illustration. Take a close look. Invite your child to use a finger to trace the veins and arteries and the flow of blood. Make sure that it is clear that blood is going through the lungs. What can happen there (pick up oxygen and release carbon dioxide)?





Compare and Contrast

Is an adult’s heartbeat the same as a child’s, as a pet’s (if the pet is cooperative)? (If the pet is not a mammal or a bird, such as a lizard, its heart may be constructed differently in terms of the number of chambers, so depending on what type of animal it is, look up the shape and function of its heart).




Examine material on the hearts of other animals, comparing shapes, size, and numbers of chambers.


For example, A blue whale’s heart is 5 feet long, 4 feet wide, and 5 feet tall and can weigh upwards of 1,500 pounds. In other words, it is the size of a small automobile, and it only beats about six times a minute. To more clearly visualize that here is a link.






On the opposite end of the size spectrum is the tiny pigmy shrew. It has a very fast metabolism. Its’ heart beats up to 1,500 times a minute – that is around 25 times a second!




A normal adult horse’s heart can weigh between 3.3 – 8.8 pounds and normally beats about 38 times a minute while at rest. An elephant’s heart can weigh 30 pounds. A dog’s pulse is between 60 and 140 beats per minute (there are variations across the size and species). A cat’s pulse is 120 – 140 (though the rates varied depending on what source of information I was looking at). With your child, look up interesting information on a favorite animal. What animal’s heart is the largest, smallest, or works the fastest? Can you find a relationship between an animal’s body size and normal heart rate? What might be a reason for this?


If looking at an illustration of the circulatory system, you can compare the roles of arteries and veins. These are tubes or the “pipes” that carry blood throughout the body. Arteries carry blood away from the heart. Well-oxygenated blood is bright red. Veins carry blood back to the heart. Veins are a more bluish color because the blood is carrying carbon dioxide back to the lungs. Fine networks of capillaries link the arteries and veins.


A majority of the blood pumped through our hearts goes to our brains and central nervous systems. Compare the brain to other organs in the body (liver, kidneys, stomach).





With your child, count the number of her/your heartbeats per minute heard when listening with a cup or tube. (A resting heart rate is 60 – 100 beats per minutes. An athlete’s resting heartbeat will be slower or between 40 – 60 heartbeats per minute). (Fun fact: Consider that a hummingbird’s heart can beat up to 1260 times a minute when they are very active).




Count the number of pulses detected in a minute. (Should be about the same as above).


Repeat these measurements on other family members. Rank the results from the most to least beats per minute.


Measure your child’s heartbeat. Record that number. Next, invite your child to run in place for a minute, and then re-measure the number of heartbeats. What happened? Is it beating faster? Why? (After exertion there is a need to refuel the muscles with more blood and oxygen.) How much faster is it beating (what is the difference between the two measures)?


How big is a heart? They are usually about the size of one’s fist, so you can ask a child to make a fist and measure the height, width and circumference as an approximate measure of his heart. A real heart, however, is a little wider at the top, tapering to a rounded point at the bottom.




Invite your child to open and close her fist, or mimic a pumping heart, 70 to 100 times a minute. How does that hand feel after working so hard?


Another approximation is that a heart weighs about as much as a lemon (11 oz.). So hand your child a lemon and he can get a sense of its weight, or weigh that lemon on a scale, and consider how it is about the same as his heart. (Consider that a giraffe’s heart weighs about 26 pounds!)




A heart pumps about five quarts of blood a minute. Measure five to six quarts of water into a pot to get an image of this impressive feat.


A heart beats about 36 to 40 million times a year. Can you and your child write out this number?


Count those heart candies before devouring them. How many do you have? How many did you eat? How many are left?




To keep your heart healthy it is recommended that you engage in approximately 60 minutes of physical activity a day. Create a chart and keep track of the amount of physical activity in terms of time spent (running, walking, climbing, skipping, and stretching). Does it add up to 60 minutes?


Time this! It takes 10 seconds for blood to travel from the heart to the big toe AND back. Amazing!



Here are a couple videos that show how to make a homemade stethoscope from inexpensive materials.







Dissect a heart. Chicken and beef hearts are on sale in most grocery stores or one may come with that roasting chicken or turkey you were going to cook. Ask your child to take a look, touching it if he is okay with that. What does it look like in terms of color, shape, and size? What does it feel like to the touch, but also if picked up and squeezed? Find the language to describe these experiences.





Your child may have overheard a discussion of someone having a heart attack. You may want to ask if she has heard this term, and explain what it means, or that someone’s heart stopped beating properly and the muscle is damaged. If she has heard that this was linked to a death, you be the judge of your child’s readiness, but this can be scary and a good discussion of why hearts get sick and malfunction could provide some needed information to alleviate that fear.




There are also children’s books that explore this topic and may provide a gentle introduction to succumbing to health issues.


Grandpa’s Garden by Shea Darian, illustrated by Karlyn Holman. 1996. Ages 5–8. Every Saturday Grandpa and grandchild work in the garden, sharing words and thoughts. After Grandpa has a heart attack, his grandchild works alone for a time.


Saying Good-Bye to Grandma by Jane Resh Thomas, illustrated by Marcia Sewall. 1988. Ages 5–8. When her grandmother dies, seven-year-old Suzie and her parents go to the town where Mother grew up to attend the funeral.


Explore ways to keep a heart healthy and how to take care of it. What are heart healthy foods? What forms of exercise does your child enjoy and is he spending enough time actively engaged?




Here are recommendations for books about love and Valentine’s Day for young children. Most of these you can probably find at your library, or ask your librarian for recommendations.






Circulatory system










Carbon dioxide


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