Topic 3- Matter and Particles

Question 1

how is an atom structured?

Answer 1

there is a small nucleus made of protons and neutrons and electrons orbit around it

Question 2

give the definition for density and how it’s measured

Answer 2

• density is a measure of how concentrated a matter is
• D ( density, kg/m³)= m ( mass, kg) /v ( volume, m³)
• when mases are measured in g, and V is measured in cm³, then the units of D are g/ cm³

Question 3

give the basic properties of electrons, protons and neutrons

Answer 3

protons neutrons electrons

mass: 1 1 0
charge: +1 0 -1

Question 4

what is the Brownian motion?

Answer 4

The Brownian motion is the jiggling motion of smoke paricles in air or of pollen in water

• observation

we observe that the smoke particles move in random, zig-zag paths

• explanation

the smoke moves this way because smoke particles are coliding with air molecules. we don’t observe the air particles because they are too small.