CBSE Class 9 Answered

Atoms are so small that we cannot see them with our eyes (i.e., microscopic). To give you a feel for some sizes, these are approximate diameters of various atoms and particles:

• atom = 1 x 10^-10 meters
• nucleus = 1 x 10^-15 to 1 x 10 ^-14 meters
• neutron or proton = 1 x 10^-15 meters
• electron - not known exactly, but thought to be on the order of 1 x 10^-18 meters

You cannot see an atom with a light microscope. However, in 1981, a type of microscope called a scanning tunneling microscope (STM) was developed.

The STM and new variations of this microscope allow us to see atoms. In addition, the STM can be used to manipulate atoms.

Atoms can be moved and molded to make various devices such as molecular motors.

Science has revealed the structure of the atom. Scientists are now conducting experiments to reveal details of the structure of the nucleus and the forces that hold it together.