23:11

CONSTITUENT OF ATOM

34:53

periodic table of the first twenty elements

18:19

SEQUENCE PART 1

13:22

SEQUENCE PART 11

1:06:16

08/01

17:47

Heron's formula (example and proof)

13:11

Electronic structure of atoms

20:16

Problema de Física: Duas Massas com uma Mola e Gravidade