Blood flows through the heart in one direction: in from the body to the right side, out to the lungs, back into the left side, then out to the body. Which way round is it? Every year it takes a minute to remember. This heart simulation puts it on the board as a beating 3D heart, cut open, with the blood moving along inside it like an animation you control. Blood low in oxygen is drawn blue and blood rich in oxygen red, and you can stop it at any step.
Step through it: six steps, one sentence each, with everything else faded so the class looks at one thing. Slow it down to follow the blood. Hide the labels and ask the class to name the chambers. Turn it by dragging. Press a name to zoom in on a chamber, a valve or a vessel and read what it does. Print a pupil sheet with blank labels, a word bank and the six steps to cut out and put in order. Press Closed to see the whole heart, with the vessels that feed the heart muscle running over the outside. Share copies a link that opens it at the step you are on.
The right side of the heart carries deoxygenated blood, low in oxygen, to the lungs. The left side carries oxygenated blood, rich in oxygen, out to the body. That is double circulation: on every lap the blood goes through the heart twice, once on its way to the lungs and once on its way to the body. Two vessels break the usual rule. The pulmonary artery is the only artery that carries blood low in oxygen, and the pulmonary veins are the only veins that carry blood rich in oxygen.
No. Blood is always red. Blood low in oxygen is a darker red, and diagrams draw it blue only to tell it apart from blood rich in oxygen. Veins can look blue through the skin, which is where the idea comes from. The simulation uses the same blue and red as a textbook, and its notes say that real blood is always red.
The model names the four chambers (right atrium, right ventricle, left atrium, left ventricle), the vena cava, the pulmonary artery, the pulmonary veins, the aorta and a valve. To use it as a label the heart quiz, press Labels once: every name turns into a question mark, and a pupil presses one to show it. The printed pupil sheet has the same heart with blank label lines and a word bank. Switch to More detail and the board adds the septum, the tricuspid, bicuspid and semilunar valves, the superior and inferior vena cava and, on the closed heart, a coronary artery.
The words are pitched at ages 9 to 14: Years 5 to 9 in England, 4th to 8th grade in the United States. In England it fits Year 6 science, which asks pupils to "identify and name the main parts of the human circulatory system, and describe the functions of the heart, blood vessels and blood". In the United States it supports NGSS 4-LS1-1, where the heart is one of the structures named, and MS-LS1-3, the body as a system of interacting subsystems, which includes the circulatory system.
What does the heart simulation show?
A beating 3D heart, cut open so the class can see inside. Blood low in oxygen, drawn blue, comes back from the body into the right side and is pumped to the lungs. It comes back rich in oxygen, drawn red, into the left side and is pumped out to the body. The blood is drawn moving along inside the heart and the ventricles squeeze on every beat.
Which way does blood flow through the heart?
Body, vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary veins, left atrium, left ventricle, aorta, body. The simulation steps through this in six stages, one sentence each.
Why is the heart's left side on the right of the screen?
Because the heart is drawn as if the person is facing you, the way every textbook draws it. Their left is on your right. The simulation says so on screen.
Why is the left ventricle wall thicker than the right?
Because it pumps blood furthest. The left ventricle squeezes hard enough to send blood round the whole body, where the right ventricle only has to send it to the lungs next door. That makes the left ventricle the strongest part of the heart.
What age is it for?
Ages 9 to 14: upper Key Stage 2 and Key Stage 3 in England, 4th to 8th grade in the United States.
Is it free?
Free to try. Opening Science Simulations uses one token for the whole day, however many times you come back to it. Every account gets 20 free tokens, and Pro gives 50 a day.
Do I need to install anything?
No. It runs in the browser on a school whiteboard, a laptop or a tablet, with nothing to download.
The respiratory system simulation shows where the blood picks up its oxygen, and the muscular system model shows the heart as a muscle. All twelve are on the Science Simulations page. For models the class can spin, from skeletons to dinosaurs, try 3D Explorer.