ACTIVITIES:
-let the kids take the model apart and let them figure out how it all fits together

THINGS TO TALK ABOUT
-What is “circulation” and why do we need it (see below)
-Structure and function of the heart
-Things that can go wrong (valve defects, heart attack etc)

TIPS FOR DEMONSTRATING:
It is quite surprising how little most people know about circulation. It is therefore very important to find out how much the kid knows already and work from that. I have included a very basic script for explaining circulation below- you would obviously have to adapt that to the age of the kid and to what he/she knows already.

BASIC PROCEDURE AND EXPLANATION

A) BASIC CONCEPTS

Look at the whole model. Ask the kids what it is (heart) and what it is used for (they will usually say that it pumps blood). Now comes the tricky bit: Why does the heart pump blood? It is quite surprising that many kids (and parents) have no idea about why we might want to pump blood through our body. If this happens, here is an explanation you could use to explain the basics of circulation (I have used a very simple one that even young kids can understand- you would have to adapt that for older kids/parents):

- Our body is made out of loads of little building blocks called cells. Each cell is like a small factory and it needs two things
- get the kids to think about what these two things may be; i.e. why do we breathe (to get oxygen); why to we eat (to get food/nutrients)
-so the factories in our body need food and oxygen
-where do they get that from? Ask them where the food they eat goes (stomach); similarly, the air they breathe in goes to the lungs
-so if the food is in the stomach and the oxygen is in the lungs, how can it ever get to all the “factories” that make up the brain, your toes etc.
- you need something like a street- these “streets” are your blood vessels
-you also need something to transport the food and oxygen, i.e. a lorry –this “lorry” is the blood
-so our blood transports food and oxygen to all the cells in our body
-but there is a problem- blood is a liquid- ask them what happens when you poor water/get water from the tap (water always “goes down”- so if this happens to our blood as well, it would all end up in our toes
- so you need something that makes the blood go to the cells in the brain as well; i.e. you need an engine to drive a lorry or in other words, you need the heart to pump the blood through your body

B) STRUCTURE OF THE HEART

Let them take the heart apart and get them to think about what the individual bits may be and what they might be used for. Here are some things you could point out:

-can they see the big blood vessels (“streets”) that come into and out of the heart; get them to think where they might come from and where they may go to; i.e. some go to/come from the lungs and others go to/come from the body (having explained circulation beforehand helps; i.e. the blood has to go to the lungs to pick up oxygen); let them guess which ones might be the vessels that go to the lungs and which ones are the ones that go to the body

- The heart has chambers –can they see them? How many are there?- how does the blood travel through the heart?

- do they think that the blood can go back to the chamber it just came from? No; point out valves; if the kids are older, get them to figure out why this “one way” system is important

- the heart is a muscle; it contracts, when it contracts, the chamber gets smaller, this squeezes the blood in that chamber into the next chamber/ into the body/ to the lungs; valves prevent backflow

C) OTHER THINGS TO TALK ABOUT

- Can they see the small blood vessels going into the heart itself (coronary arteries etc)? Why is this important? – the heart is a muscle, that has to work all the time for all your life- it needs a lot of food and oxygen, too!!! What do they think happens if you block one of these vessels?
Ischaemia, angina, heart attack (Parents are usually quite interested in this)

-What can you do when this happens? Open up vessels (stents), make vessels bigger (drugs; vasodilators); but most importantly, remove anything that can block those vessels- this is why a healthy diet, exercise and stopping smoking are so important!

-Other things that can go wrong: Valve defects, heart failure

-When the heart pumps, it makes a noise- this is what you can hear with a stethoscope; refer them to the stethoscope experiment