lesson one (hydrosphere)

lesson two ( part 1)

lesson two ( part 2)

lesson three ( density 1)

lesson three ( density of water )

lesson three ( heat 1)

lesson three ( heat 2)

lesson four ( solution )

lesson five ( part1)

lesson five ( part2)

lesson six

lesson 7

task 1

task 2

task 3

task 4

task 5

task 6

lesson 8

lesson 9