4.6 Role of water  (Page 3/3)

This is evident when the learner:

• evaluates data and communicates findings.

LO 2: Constructing Science Knowledge:

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

This is evident when the learner:

• interprets information;

2.4 applies knowledge.

LO 3: Science, Society and the Environment

The learner will be able to demonstrate an understanding of the interrelationships between science and technology, society and the environment.

This is evident when the learner:

3.2 understands sustainable use of the earth’s resources.

Memorandum

Activity: The value of water and the water cycle

Own representation of the water cycle:

Check to ensure that the learner has included all the relevant terms in the table in his / her sketch.

El Niño, droughts and floods

1. Help the class to select and record the best information from the learners' feedback / presentations.

2. As in 1.

Activity: Water in and around the home

Learners collect information about water consumption. Encourage them to give their own opinions on the level of their personal consumption of water.

Water Conservation at home

• How might your family be able to contribute towards water conservation?
• Draw up a list of the best suggestions.
• Let the class decide on the best suggestions in the list. Praise the learner whose list resembles this list most closely.

Activity: Adaptations to water shortage that occur among plants and animals

Three groups, with examples : mesophytes (any example), xerophytes (e.g. the aloe, other succulents, prickly pears, etc.), hydrophytes (water lily, etc.)

Design : Note fleshy leaves, frequently small and sessile, arranged in such a way that they lead water towards the stem of the plant. Leaves may also be extremely small and thorn-like. May be covered with a waxy layer. Shallow roots, excessively branched.

Assignment:

• Examples (accept whatever is significant):

• Plants

• Hairy leaves
• Few openings (stomata)
• Openings occurring on lower sides of leaves only
• Fleshy stems and roots
• Enlarged underground parts in which water can be stored

• Animals

• Small body surface
• Little or no excretion of urine
• Dry excrement
• Few blood vessels near the skin in large areas of the body (Because of this, the body cannot be cooled properly and other mechanisms are developed for cooling specific areas, e.g. the brain. In the case of the Cape oryx, for instance, blood that goes to the brain is circulated through the nostrils where it can be cooled down.)
• Eating food with a high moisture content

Acquaint the learners with the following concepts:

Panting: fast breathing with high loss of moisture from the mucous membranes of the throat and mouth, as in the case of dogs and some bird species

Estivation: passing the summer in a dormant condition. It is cooler below the surface of the soil – this is why some animals use tunnels.

Migration: Birds, in particular, as well as some antelope species, migrate to areas that offer better sources of food, even seasonally, e.g. swallows.

Rete mirabilis : A miraculous network of blood vessels in the nostrils of the Cape oryx for cooling the blood.

Survival strategies of animals

• Oryx: shade of trees, and keeping the brain cool by circulating blood through the nostrils.
• Mongoose: shelters underground.
• Migrating to where there is water, no respiration through the skin – no moisture is lost, but cooling down by flying.
• Perspiring through the tongue only.