Water and minerals

1.

WATER and MINERALS

2.

Lesson objectives
To explain the properties of water
fundamental importance of water for life
on Earth.

3.

How can small animals walk on
the surface of water?

4.

5.

6.

Properties of water:
Water is common solvent.
It is media for biochemical reactions
Cohesion and adhesion of water
High surface tension.
High heat capacity
Ice float on water

7.

Water is versatile solvent
Many nutrients are transported in dissolved
form.

8.

Cohesion and adhesion of water
Water molecules stick close to each other. This is
called as cohesion.
Adhesion is ability of water molecules to stick on
other surfaces.
Cohesion and adhesion both help to pull water
molecules upward in the vessels of plants.

9.

10.

High surface tension.
Surface tension is the tendency of liquid
surfaces to shrink into the minimum surface
area possible.
At water-air interfaces, water molecules have
greater attraction to each other due to
cohesion.

11.

It causes the
water to behave
as its surface
was covered
with elastic
membrane

12.

It allows insects to walk on water surface

13.

High heat capacity
Water melting point is 0ºC
Water boiling point is 100ºC
A lot of energy is needed to heat water
Excess heat is used to vaporize water
during sweating process.
So it helps to keep temperature relatively
steady .

14.

Excess heat is used
to vaporize water
during sweating
process.
So water helps us to
keep body
temperature steady.

15.

Ice float on water
Ice floats because it is less dense than
liquid water.
It allows aquatic animals to survive under
the frozen surfaces of lakes and polar seas

16.

17.

Let’s do labwork on p.35

18.

Homework
Copy the PPT
Read p.34-35
Answer to post-lab and pre-lab questions on
p.35
New words
Fill in the labwork table