Question 1

Is the US gallon the same as the UK gallon?

Accepted Answer

No. The US gallon is 3.785 L and the imperial (UK) gallon is 4.546 L — about 20% larger. Pints differ too: US 0.473 L, UK 0.568 L. This makes mpg figures incomparable between the two countries.

Question 2

What is an oil barrel?

Accepted Answer

One oil barrel = 42 US gallons = 158.987 L ≈ 159 L, a leftover from real wooden barrels. Crude is quoted in dollars per barrel; at $80 a barrel that is about 50 cents per litre of crude before refining.

Question 3

How many litres are in a cubic metre?

Accepted Answer

Exactly 1,000 L by definition. Also 1 dm³ = 1 L and 1 cm³ = 1 ml. A 25 × 10 × 1.5 m pool holds 375 m³ = 375,000 L. Typical household water use is 150–200 L per person per day.

Question 4

How is engine displacement measured?

Accepted Answer

In litres or cubic decimetres. A "2.0" engine displaces 2,000 cm³ = 2 L = 2 dm³ of cylinder volume. The US historically used cubic inches (1 L ≈ 61 in³), so 350 cubic inches is 5.7 L — the classic American V8.

Question 5

What is a cubic metre of gas?

Accepted Answer

It is 1 m³ of natural gas at standard conditions, with a heating value of about 35 MJ/m³. The gas meter counts in cubic metres. Heating a 60 m² flat in winter can take roughly 200–400 m³ per month.

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