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Data and Society 9-12 / Week 10 / Tuesday
2/6
Week 10 · Models and Simulations

Tuesday

Simulations
// Can a simple model predict what will happen next?
⏱ about 20 min

Tuesday: Simulations

Comet has a new plan. "Let's skip the model. We open a real repair bench for a month and just count!"

"The trial bench was borrowed for one day," Wren says. "A bench for a month is what the council is deciding about. What do you notice about your plan?"

Comet taps her pencil on her notebook. "It needs the very thing we are trying to decide."

Nova hovers over the table and sets a small die in Comet's hand. "Would you like a hint?" she asks. "Something small can stand in for something big, if you choose its rules with care."

Comet rolls. A 2. "Someone just arrived at a bench that does not exist," she grins.

Wren smiles. "Then let's see what happens over a whole afternoon."

What is a simulation?

A simulation is a simplified version of something more complex. It is made for a specific purpose.

A simulation uses changing values to show how a situation changes. Each die roll changes the state of the line.

Simulations let people investigate a situation without the limits of the real world. The crew can test a bench they do not have.

Run one hour

Here is the first hour of one run, using the first rule: a 1 or 2 means one person arrives.

SlotRoll
1 (first 10 minutes)4
21
36
42
52
6 (last 10 minutes)5
RUN THE FIRST HOUR
  • Read the question.
  • Tap your answer.
In which slots did someone arrive?
How many arrivals happened in this hour?
After slot 4, how many arrivals had there been so far?
The first rule expects about how many arrivals per hour?

What gets left out

Building a simulation means removing details or simplifying how things work.

A simulation can carry bias from the choices about what was left in or left out.

The first rule treats every 10-minute slot the same. Look at the Saturday door count from week 4 to see if that is true.

Hour (Saturday door count, made-up data from the Commons Count story)People through the door
10 am5
11 am8
12 pm6
1 pm7
2 pm9
3 pm11
4 pm14
5 pm16
6 pm12
7 pm7
BUSY AND QUIET HOURS
  • Read the question.
  • Tap your answer.
Which hour had the most people through the door?
Which hour had the fewest?
The die rule gives every slot the same chance. What might it miss?
StatementTrue or false?
A simulation is a simplified version of something more complex.?
A simulation is made for a specific purpose.?
A simulation shows every detail of the real situation.?
What is left out of a simulation can add bias.?
WHY THIS EXERCISEEvery simulation is a trade: simpler to run, but missing something.
RUN ONE SLOT
  • ?Move on to the next slot.
  • ?Read the number on top.
  • ?Mark an arrival or no arrival.
  • ?Check the number against the rule.
  • ?Roll the die once.
WHY THIS EXERCISERunning a simulation by hand shows each step the model repeats.
A simplified stand-in for a real situation, made for a purpose, is a ____. Type one word.
WHY THIS EXERCISENaming the tool helps you explain what the crew is doing with the die.
On paper, sketch a line graph of the Saturday door count. Shade the hours where an even die rule might miss the rush.

Great work. Tomorrow in Count Lab you will roll all 36 slots yourself.

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