Physics and Natural Sciences
How heavy is the air in this room?
Estimate the mass of the air in this room. Is the answer more or less than you expected?
- Hint 1Estimate the room's length, width and height.
- Hint 2Air has a density of about 1.2 kg per cubic metre.
- Take a room 5 m by 4 m by 2.5 m: 50 m³.
- Mass ≈ 50 m³ × 1.2 kg/m³ = 60 kg.
- That is about the mass of an adult, which surprises most people.
- We do not feel it because the air pushes equally in every direction.
Where it lands: About 60 kg for a 5 m × 4 m × 2.5 m room.
The trap: Getting the units wrong: air is about 1.2 g per litre, which is 1.2 kg/m³, not 1.2 g/m³.
What a tutor might ask next: What is the total force of the air on the floor, and why does the floor not collapse?
Now do one out loud. In the interview you think aloud with a tutor. Try a Physics problem with hints, follow-ups and Mia's feedback on how you think.