Generally, because of their small size, we can't see atoms. The information about atoms has to be inferred from how they behave.
For example, Rutherford's gold foil experiment told us that atoms are not solid, they have dense nuclei surrounded by space. Rutherford bombarded very thin gold foil with helium nuclei (small and heavy) and then used a detector to find where the helium nuclei ended up. He found that most of them would pass straight through the foil but some were deflected and even bounced straight back. This is a little like throwing Golf balls at a wall with holes in it, some golf balls go through the holes and some bounce back.
Scientists can bounce electrons off crystals to determine shapes and structure; they can rip electrons off vaporised atoms and then accelerate the atoms towards a magnet that deflects them. This enables the size of the atoms to be determined.
The Large Hadron Collider (French/Swiss border) accelerates ions and protons in a vacuum and allows them to collide, these high speed collisions, with the use of appropriate sensors, enable the scientists to identify and study atomic particles that are generated by the high energy impacts.
a electron microscope
A compass.
A seismograph
lectometer
Anemometer
a scale
This instrument is a balance.
A tiltmeter measures changes in the tilt of the earth. :)A tiltmeter is an instrument that measures changes in the tilt of the earth. :)
A calorimeter measures heat. In contrast, a thermometer measures temperature.A thermometer bolometer - an instrument that measures heat radiation; extremely sensitive calorimeter - a measuring instrument that determines quantities of heatHeat is measured with a ThermometerThermometerThermometer or calorimeterThermometerthermometerHeat is measured with a thermometer.
A thermometer measures molecular energy.
a calender
ruler
An aeroplane
spirometer
grams
A ruler
a creep meter
A sextant