Steel is denser.

Aluminum is 2700 kg/m3

Steel is 8000+/- kg/m3

Grade 33 cement doesn’t have a number of grades, but is a strength rating of the cement mix. At 28 days of curing (number of days since it was mixed and poured) it will have a minimum compressive strength of 33N/mm2.

There are two major uses that cladding has. Keep in mind that the use of rocks is just the material of choice in this case.

First, cladding is used as a durable and/or protective layer over your building membrane. In older or more advanced examples it may also be or include the membrane. (The building membrane, in this case, would be the water and/or air barrier system such as building felt or Tyvek.)

Second is just aesthetics. People like the way it looks, and reminds them of classic archetypes.

The concept of floating is called buoyancy.

Basically, if the density of the object is lower than density of the material it is in it will rise until it meets an equal or lower density. This example assumes that your object is in a liquid or gas.

If you don’t include permafrost or glacier ice there is probably slightly more potable water today due to storage and filtration.

This would be difficult to answer as today’s criteria for potable water is stricter than would have been used 500 years ago. As such many water sources used 500 years would be considered unsuitable for human consumption.

So if you used today’s criteria I would think we have between 10 to 30 times the amount of potable water today.

To respond to Mark’s analogy of organic life compared to computers:

Birth – Assembly

Growth – Data and/or program storage

Stop growth – Data capacity

Feeding – Electricity or material processing (if applicable)

Self-healing – Recalibration (organic life also has a very limited ability to self-heal in proportion to damage)

Reproduction – von Neuman machines; not all life does or is capable of reproduction, but this is a designable criteria

Death – Critical failure

Additional virtually all organic life can be broken down into recognizable hardware: pumps, pipes, electrical systems, sensors, chemical reactors … We are just beginning to understand the software side. DNA seems to be like Read Only Memory, RNA is a form of signaling, as is nerve impulses. Our senses (sensors) gather additional information from our environment.

Is there more? Probably, but we don’t know enough yet.

At what point does a machine become alive? The line in the sand seems to be drawn (arbitrarily) between viruses and bacteria. Why? Because the scientists at the time were asked that very question, and the group agreed to place it there.

If they are touching the toaster; yes. Otherwise the current will be too dispersed to cause damage to them.

In the short term, you can acquire more property with less assets by renting. (You may pay more each month, but you didn’t need a huge downpayment.) Additionally, you tend to be less liable for the same property.

This means, again in the short term, that it is better for leverage and liability.

You get what is called “Well Graded Soil”. Basically, each fills in the voids left by the larger grained material.

In most cases yes. Don’t drink it if it has a different color, taste or smell.

Water from a water cooler is fine for months (sometimes even years).