Curious Facts Quizzes / Everyday Life · 3 questions
What does the gap in a flask do?
Three questions distinguish the gap’s location, its role and reflective surfaces.
No prior knowledge is needed. Choose an answer to see the explanation and evidence.
1Understanding
Where is the vacuum gap in the flask described here?
Correct answer: Between the inner and outer walls
The gap is between the walls. The account does not empty the drink chamber itself.
Evidence: The vacuum gap lies between the inner and outer walls, not in the chamber holding the drink. The gap is between the walls. The account does not empty the drink chamber itself.
2Understanding
What is the main purpose of removing air between the walls?
Correct answer: To reduce conduction and convection across the gap
The particle-poor gap reduces conduction and convection, without making the entire product perfectly insulated.
Evidence: A vacuum greatly reduces conduction and convection across the gap, but it does not block all thermal radiation. The particle-poor gap reduces conduction and convection, without making the entire product perfectly insulated.
3Context
Why can a reflective surface be useful in addition to the vacuum gap?
Correct answer: To reduce heat transfer by radiation
Radiation can cross a vacuum. Reflective surfaces reduce this heat-transfer route.
Evidence: Reflective surfaces can reduce heat transfer by infrared radiation. Radiation can cross a vacuum. Reflective surfaces reduce this heat-transfer route.
Quiz complete
Quiz results
Your first-attempt score stays the same. Review rounds are recorded separately.
Review history
Questions missed on the first attempt
Compare your answer with the correct answer, then explore the explanation and evidence.
You answered every question correctly. Revisit the takeaway, then explore something new.
Connected reading
Where is the vacuum in an insulated flask?