Gas lines in homes are most often done in flexible copper tubing. A fairly new product also being used that is easy to spot is the yellow flex pipe a "flexible, yellow polyethylene coated copper tubing that is continuously line-marked for clearer identification of liquefied petroleum and natural gas." It would come in various sizes- 3/8" to 3/4" or even more for industrial applications.
Black iron or galvanized pipe is also commonly used.
They look like a regular clump of rock. They are called rough gemstones.
In America it should be 60hz. But you can hook up a power meter to the line and find out the real frequency and voltage of the common household or office power line. You may be surprised at the number of spikes and drops in voltage and frequency in a household line. A good UPS can some times tell you as well.
2 endpionts at the end of aline
An airplane is based on a bird. A fishing net is based on a spiderweb. And an umbrella kind of looks like a mushroom.
you cant really see natural gas just like you cant see wind or air but it there none the less. You can't see it, you can only smell it I think. natural gas is in a vapor form and isn't visible by the human eye. The only you can smell natural gas is because they add a sulfur scent to it for safety! Definitely do the "sniff test" if you're concerned about leaking natural gas!
dark look
a straight line
A curved line is a line that is curved.
A linear line is a straight line
When supply and demand are perfectly elastic/inelastic
a line across
If the line has ends, then it's a line segment.
The plumb line is a vertical straight line.
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a line
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