Metric yardstick
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A metric yardstick is a rough rule of thumb for comprehending a metric unit in terms of everyday life in the United States.
Contents |
[edit] Metric yardsticks based on everyday objects
[edit] Length
- One meter equals roughly one (longish) step of a tall adult man. Two cubits as perceived by such a person may come to about one meter.
- The length of a one-second pendulum is approximately one meter.
- One kilometer equals ten minutes' walk.
- The distance between nails of fingers pressed together is roughly 1 cm or 10 mm.
- the width of a fingernail is roughly 1 cm.
- The cubit arm (forearm from elbow to fingertips) is roughly 50 cm. This is known as metric cubit and has been used in some countries.
- The width of man's hand is about one decimeter or 10 cm. That is almost the same as the old English unit "hand".
- The side of a matchbox is 5 cm.
[edit] Area
- A large soccer field has an area of one hectare (10,000 square meters).
- The area covered by a large umbrella is roughly one square meter.
[edit] Volume
- A cube of one hand (1 decimeter) per side is equal to one liter.
- A drop of water (or water-based solution, like milk, tears, etc.) is very close to 0.05 milliliters. 20 drops make one milliliter. This is an approximation used in chemical engineering. One liter is therefore roughly 20,000 drops.
- Both the British and American pints are close to 1/2 L, sometimes called the "metric pint".
- Soft drinks are sold in 1, 1.5, 2 and 3 liter bottles.
[edit] Mass
- One liter of water weighs one kilogram, and therefore 1000 liters of water (a cubic meter) weighs 1 tonne.
- One tonne (1000 kg) is roughly the mass of an economy motor car.
- One U.S. "nickel" (5 cent coin) has a mass of 5 g.
- One litre of soda has a mass of roughly 1 kg.
[edit] Force
- A small apple on Earth exerts a force due to gravity of about one newton (N).
- One kilogram at the Earth's surface exerts a force due to gravity very close to 10 N.
- One newton-meter torque is roughly the increase in torque by adding a small apple to the end of an outstretched walking stick.
[edit] Temperature
- For Celsius temperatures
- 30 is hot
- 20 is nice
- 10 is chilly
- 0 is ice.
- Normal room temperature is roughly 22 °C
- An outside temperature of 300 kelvins means bikini weather.
[edit] Pressure
- Normal air pressure at sea-level is around 100 kilopascals. It equals approximately 1 kg/cm2
- Every ten metres' depth of seawater exerts about one bar or 100 kPa or 1 kg/cm2 of additional pressure.
[edit] Conversion hints for Americans
For users of the English system, mostly Americans in the 21st century, there are a few simple equivalents and conversion factors that help in learning to be comfortable with the metric system:
[edit] Near equivalents
The following units are the same within a few percent. The slightly larger unit is listed first
[edit] Approximate conversion factors
- 1 mile ≈ 1.6 km
- 1 meter ≈ 1.1 yard / 1 yard ≈ 0.9 meters
- 1 kilogram ≈ 2.2 lb
- 1 inch ≈ 25 mm
- 1 cup ≈ 250 ml
- 1 teaspoon = 5 ml
- 1 ounce ≈ 28 grams
- 1 acre ≈ 4000 square meters ≈ 0.4 hectare
[edit] Celsius landmarks
The table below lists easy to remember or particularly important Celsius temperatures.
| °C | °F | Landmark |
|---|---|---|
| -40 | -40 | Exact |
| -11.4 | +11.4 | |
| 0 | 32 | Freezing point of water, exact |
| 4 | 40 | |
| 10 | 50 | Exact |
| 16 | 61 | |
| 22 | 72 | Room temperature |
| 28 | 82 | |
| 30 | 86 | Beach weather, exact |
| 37 | 98.6 | Body temperature |
| 40 | 104 | Hot tub, exact |
| 100 | 212 | Water boils, exact |
