You put it on a scale
Tools or their hands.
a plumber uses a chisel
He used celestial objects and compass.
gramsWHAT
Magnifying glass, telescope, microscope, television etc.
Magnifying glass, microscope, and telescope are tools that make objects appear larger. They use lenses to magnify and focus light to enhance the visibility of small objects.
Some tools that use lenses to refract light include cameras, microscopes, telescopes, and eyeglasses. Lenses in these tools bend and focus light to produce clear images or magnify objects.
probably a microscope or magnifying glass.
Atomic weight is used for historical reasons. It was the first science to investigate the same physical objects.
by using certain mechanical objects, like a pulley, you can use the object's own weight to its advantage. Also, by exploiting gravity and the object's own weight, you can use inertia to roll the object down the hill or yet better in a free fall.
Kilogram is a measure of weight - so you would use it to weight something. You would probably use it for objects that are large enough to make using grams unnecessary.
A person who makes iron tools is commonly referred to as a blacksmith. Blacksmiths use traditional techniques to shape and manipulate iron into various tools and objects.