How To Ask Fermi Questions Examples for Teachers

What Are Fermi Questions?

A Fermi Question requires a quick, estimated answer which would be impractical to measure directly.

Students are expected to answer Fermi Questions with very little information or data to support them. Fermi Questions therefore promote both creative and logical thinking.

The answer to a Fermi Questions should not be something that is easily calculated, already commonly known or easily found.

Fermi Questions are named after physicist,  Enrico Fermi, who was renowned for making good, accurate estimations using order-of-magnitude calculations in his head.

These are very beneficial questions and it is important that teachers understand how to ask fermi questions in lessons. 


18 Types Of Questions

Teachers Can Ask In Lessons

Fermi questions are just one of many question types that teachers can ask in lessons.

Read this article to explore other types of questions you could use in your lessons. 

VIDEO: Fermi Questions Explained

20 Examples of Fermi Questions

These examples will give you a flavour of what a Fermi Question is and you will easily be able to come up with your own Fermi Questions using similar ideas. 

Here are 20 examples of Fermi Questions that you could use in your lessons.

  1. How many balloons can you fit in an Olympic size swimming pool?
  2. What is the total mass of all the cars that were scrapped in the UK last year? 
  3. How many hairs are on your head?
  4. How many hours do you spend brushing your teeth in your whole life?
  5. If every person in the UK held hands, how long would the line be?
  6. How old would you be if you were one million days old?
  7. How many dogs could you fit in your classroom?
  8. How many cups of tea are drunk in the UK every year?
  9. How many gold fish would be needed to equal the weight of a blue whale?
  10. If you would walk to the moon, how long would it take?
  11. How many blades of grass are in a football penalty area?
  12. What is the total number of bricks in the school building?
  13. How many words to the children in this school read in a year?
  14. How many trees are currently in the UK?
  15. If everyone in Europe moved to France, would they fit and, if so, how crowded would it be?
  16. What is the total number of emails sent each day by students and teachers in the school? 
  17. How many railway stations are there in the UK?
  18. If you walked in a straight line for 1 year how far would you travel?
  19. How many tennis balls would it take to fill the school bus?
  20. How many traffic lights are there in a 10 mile radius of the school?

When and How To Ask Fermi Questions In The Classroom

Fermi questions can be used at any stage of a lesson. 

You can use a fermi question as a starter activity to engage students in a productive way through their participation in the discussions and collaborative working that is required to provide a response to a fermi question.

As a starter activity the students would either need to refer to their prior knowledge and assumptions of the topic or work with their peers to determine the information they need to produce a response.  

Similarly, you could use a fermi question at the end of a lesson as part of a plenary. In this example you could ask a fermi question which requires students to produce an estimated response using some of the information and ideas generated in the lesson. 

Ultimately, fermi questions can be used at any stage of a lesson, whenever the teacher considers it appropriate and beneficial to student progress.

What Are The Benefits Of Asking Fermi Questions In Lessons?

Fermi questions are an excellent way to promote critical thinking, abstract thinking, creativity and also logical thinking. 

Fermi questions are also fun to explore and from my experience students tend to actively participate with little need for encouragement. 

However, it is sometimes quite challenging to directly link fermi questions to the specific topic you are teaching. This is due to the abstract nature of fermi questions. 

Therefore, fermi questions are often used with the main purpose of promoting the type of thinking outlined above. 

If, as a teacher, you would like to develop your students’ abilities to think in a more divergent way, generate responses with limited information and work collaboratively with their peers, then understanding how to ask fermi questions can be a great tool for achieving this.

Author: Jonathan Sandling