In A World of Systems

[Music] meet Marcel Cynthia and Kiki or rather meet Marcel's circulatory system Cynthia's nervous system and Kiki's digestive system not only are these three made of systems but they're also part of systems like the family system that connects them together tonight Marcel and Cynthia are PR preparing to host their good friend Alex for dinner Cynthia worked all afternoon in the garden and her basket is full of freshly picked vegetables now they need to get ready Cynthia goes upstairs to take a shower and Marcel heads to the kitchen to cook Cynthia is still thinking about those tasty

peas she just harvested she's certainly not thinking about systems little does she know that she's about to enter one right [Music] now a shower is a convenient way to clean up but it's also a system we can think of a system as a set of parts that are connected to one another and organized to achieve a certain goal in this case the goal is to bring heated water upstairs for Cynthia and Marcel to use but watch what happens when Cynthia goes to start her shower Cynthia herself is a part of the shower system and her

feedback will help her get the temperature just right eventually every time Cynthia adjusts the shower handle she brings the temperature closer to where she wants it while Cynthia is finally happy in the shower here's a way of looking at the system water is Flowing from the shower head at a certain temperature Cynthia knows what temperature is ideal for her and the nerve endings in her hand perceive a gap between the current temperature and her desired temperature which makes her turn the handle to adjust the temperature of the water closer to the level she wants altogether

these actions feed back into each other in a loop that can be repeated until the desired temperature is reached here's the same feedback loop presented in a different [Music] way a feedback loop that is self-correcting is called a balancing feedback loop but why does it take so long to get the temperature right well that delay is part of the system too the shower system continues from the bathroom upstairs all the way down to the water tank and the heater in the basement and it takes time for the heated water to travel through the pipes because

delays are important forces in systems we better add one to our feedback loop voila we place it here to indicate that it takes time for the temperature adjustment to result in a change in the water temperature in this shower system we also mentioned the water tank and the heater the water in the tank is a good example of a stock a quantity that can grow over time as a result of an inflow and can decrease over time as a result of an outflow so the stock of water in the tank receives an inflow of cold

water and releases an outflow of heated water for Cynthia to use Marcel in the kitchen is also drawing from the stock of hot water as he washes some fishes the shower system is just one part of The house's larger water system but systems extend far beyond water or the house at that very moment Marcel gets a call from Alex he's on his way but stuck in traffic something is causing a major backup on the roads Alex has driven this route a 100 times without DeLay So what's going on well there's been an accident on the

highway that's slowing everything down normally cars would be flowing through the highway smoothly but today they're at a standstill cars keep entering the traffic jam from the back but no one can move until the accident is cleared up the outflow in this system is all blocked and it looks like Alex might just have to wait it out unfortunately it seems that no one is very patient at this time of day trying to get home for dinner someone in a car nearby honks his horn now that no one is moving a social system has been added

to the traffic system and Alex is on edge the woman behind him keeps trying to nudge her car up even though there isn't any extra room Alex is getting more and more tense and so are the drivers around him the whole thing is quickly escalating into quite a mess why is everybody getting angrier well just like Cynthia responding to the temperature of her shower the people in this traffic system are responding to one another in a feedback loop but rather than bringing the system into balance they're driving it further and further to the extreme as

Alex's anger increases his expressions of anger make other drivers around him angrier and when angrier their expressions of anger escalate into a frenzy of gestures and offensive words that make Alex angrier here's the same feedback loop present it in a different way this type of feedback loop is called reinforcing because it gains strength at each cycle but back in the traffic jam something is happening luckily just as things are threatening to get out of hand a traffic sign lights up with details about the delay now that he knows what's going on and has some information

to plan with Alex starts to relax he imagines new additions to the transportation system to speed things up and avoid traffic a well-trained raptor to the rescue or a more feasible Light Rail could do the trick how pleasant it would be to step on a train and be able to bypass the highway entirely and finally the traffic starts moving again phew surely that transportation system was complicated enough for one night right well not exactly back at the house Marcel proudly shows Cynthia the fish he picked out at the fish market earlier today but purchasing a

fish is only one very small part of the fishery system that Marcel is now a part of this seemingly simple entree where did it come from Marcel's fish started out in the ocean as part of a school of fish the school is itself a system and like the shower and the traffic system it has flows new fish flow into the school as fish reproduce and fish flow out because of fishing predators and because of natural deaths if the outflows Matched the inflow of new fish the fish population would stay fairly stable that would be a

healthy fishery but as it turns out Marcel isn't the only one who enjoys a nice fish filet now and then demand for fish is high fishing is increasing and the stock of fish is shrinking There are rules in place to try to protect the fish schools fishermen can only fish for a certain part of the year the fish they take must be a certain minimum size and any individual can Harvest only so many fish but the people who made those rules had only imperfect information on how many fish are left and they may have been

thinking more of today's economic returns than the long-term health of the fish stocks the system has been set up to deplete itself in a system designed to maintain a healthy stock of fish in the long term would Marcel have been able to afford that fish he bought would there be that species of fish for sale at all of course none of these complexities are on Marcel's mind he sets the table he's just happy that the fish is ready and looking tasty Cynthia feels refreshed from her shower and Alex finally pulls into the driveway to join

them they all sit down to enjoy a nice meal together while they're lost in the evening's delicious food and pleasant company it's easier to see the systems that made it all possible the house is water system the neighborhood's transportation system the nation's fishery system and many many more including the system of friendship that binds these three together [Music]