Look for a manufacture that supplies a mechanical gauge and check directions for location it depends what the size fittings they use.
if v8 it is in water neck or right behind on intake mantifold /strait 6 water neck or intake on side moter
Mechanical.
1- Soldering 2- Brazing 3- compression 4- flair 5- Mechanical joints 6- adapters to IPS system
Yes, like all other mechanical devices.
No; water in a fish tank is not a mechanical mixture. It is a homogeneous mixture. Mechanical mixtures are heterogeneous mixtures.
To answer you question more thoroughly I will need more detail because there are several different types of water qauges. You have a water temperature gauge, water pressure gauge and water level gauges.
No, chemical because it involves water and water is a subject of Chemical Weathering not Mechanical.
On the housing where the thermostat bolts on, just above the water pump and below the upper rad line (the suppily), there is a temperature sensor. Remove it, install a Tee into the fitting and reinstall the temp sensor in one of the legs of the Tee, and the sensor from the after-market gauge in the other. run the sensor wire through the firewall and up to the gauge in the dash. Connect the lights to the gauge and there you go. On my 4cyl there was another temperature sensor at the back of the head (up close to the firewall) that went to the dash idiot light. I suppose you could pull it, and install the sensor there. But I kinda liked having the idiot light as a backup. The sensor in the front that you are teeing into is the one that measures engine temp for the computer, so make sure that you reinstall it.
Wind, water, animal, and mechanical
Mechanical waves require a medium (substance) to travel in, other waves do not. For example, sound is a mechanical wave and require a medium (air, water, etc.), light is not a mechanical wave and does not require a medium
Water.
A rain gauge looks like a water bottle and collects the water and then after the water is collected you can see the answer.