Guesstimation and Fermi Problems
Thursday, May 20, 2010
How do you decide... When it’s safe to cross the street? Which line will be fastest at the movies? How many pizzas you need to buy to feed your friends?
Thursday, May 20, 2010
Estimation!!!
Thursday, May 20, 2010
Fermi Problems AKA Fermi estimates or “back-of-envelope” problems Solved using “best guess” or justified approximations Useful for finding reasonable answers (close enough) A great way to work on out-of-the-box thinking! Thursday, May 20, 2010
Enrico Fermi Famous Italian physicist Well known for solving difficult problems in his head Used a combination of common sense, intuition and data
Thursday, May 20, 2010
How do you solve them? Understand the problem Think of a plan Carry out the plan Look back, is your answer reasonable?
Thursday, May 20, 2010
The Problem:
How many ping pong balls would it take to fill this classroom? Thursday, May 20, 2010
Understand the Problem What are you asked to find? What information are you given? What information do you need to find, measure or approximate?
Thursday, May 20, 2010
Think of a Plan This is a volume problem How many small things can fit into a large thing?
# small things = (large thing Volume) รท (small thing Volume) What assumptions or approximations are you going to make?
Thursday, May 20, 2010
Carry Out the Plan What is the volume of this classroom? V=HxWxL What is the volume of a ping pong ball? V = H x W x L OR V=4/3ฯ r3 # ping pong balls= (room V) รท (ball V)
Thursday, May 20, 2010
Look Back
Does the answer seem reasonable? Is there a way to improve your estimate? Look at each assumption you made
Thursday, May 20, 2010
Now you try some!!!
Thursday, May 20, 2010
Name _________________________________________________ Date ______________________
Figure Out Fermi Enrico Fermi was a famous Italian physicist well known for solving difficult problems in his head, using a combination of common sense, intuition and data. Directions: Following is a list of common Fermi problems. Your challenge is to work in pairs or table groups to figure out the answers. Hint: You will need to collect some basic information for each question before you can solve the problem. 1. What is the total weight of all the students in our school?
2. How many hours of TV will the students in our class watch this year?
3. How many minutes will all the students in our school spend on their cell phones this school year?
4. How many times does a person始s heart beat in a lifetime?
5. Now, create one of your own Fermi-style problems below.
Thursday, May 20, 2010