The Environment - Soil Types (Lessons 1 & 2)

 FOCUS QUESTION

Why is it important to care for the environment?

SPECIFIC OBJS.

1.       Investigate features/soils of different environments

CONTENT SUMMARY

Soil is a valuable resource. It has different layers. We need soil so that we can grow crops for our food and to feed animals. The plants that grow in soil can help[ reduce carbon dioxide in the atmosphere and protect us from high winds and waves. Many animals need soil in order to survive. Soil can easily be spoiled and this is called degradation. Soil that is damaged can easily be blown or washed away. This is called erosion.

Layers of soil

DAY 1

ENGAGE

Students will be engaged in a discussion on where soil comes from and what it comprise.

Students will be asked to take out their soil samples they were asked to collect. They will label them as to where they were taken from. Soil from sea, the garden etc. They will manipulate the different types, and tell if they think the properties are the same.

EXPLORE

Examine the chart below and  see if any of the soil types you found looks like the ones in the picture below.

Students will carry out an investigation in their groups, they will pour water on the different soil types in transparent containers and stir, then allow them to settle. They will examine the different layers that will be formed.

 They will record where the different particles drop ( ie. sand, small particles, humus). They will tell why they believe they fall in that order. Students will tell what else is in the soil?  They will later identify soil as a composition of dead plants and animals, bacteria and humus.

Watch the video clips below to gain more insights on types of soil and their characteristics.

Characteristics of soil

EXPLAIN

Tell what soil is, the different types there are,  and what soil is made up of.

EXTEND/ELABORATE

Students will complete the table below in their groups.

Soil Type	Sandy soil	Chalky soil	Clay	Loam
Properties(colour, texture,

Make your notes from the content summary.

EVALUATE

1.  Write a report on your observation of the soil types, when mixed with water.

2.  Explain what humus is and why it so important to soil.

3.  Based on information gleaned from video clips and experiments done, answer yes or no for the following statements.

STATEMENTS	YES	NO
Soil has dead plants and animals material in it
Soil does not contain bacteria
Humus serves as nutrients for soil
All soil types are the same

 

Day 2

ENGAGE

Let's watch this video clip together and then do a discussion.

Soil type

So would you say that all soil types are the same?

Do they all hold the same amount of water?

Which would be the best to plant a crop of peas?

EXPLORE

Now you will be performing an experiment in a while with the different soil types. First I want you to pay attention to the activity that will be done in the video clip below. Let's review what ensures a FAIR test.

We will be poring water into the containers with the different soil type to find out which type will retain more water.

First I want you to formulate a hypothesis.

What will be the dependent, independent and control variables?

Look at what was done to ensure that the test was FAIR.

Soil Retention

Now you can  perform the  simple experiment with your soil samples.  Please pay attention to the questions you will need to answer at the end of your experiment.

(Fixed amount of water should be added to all plastic funnels, and you will pour a fixed amount of water to all the different soil types. You will measure the time taken for each to pass through each funnel with soil type. Answer questions  that follow:

(a)    Which soil type held the most water?

(b)   What does this suggest about the water-holding capacity of the soil?

(c)    Which type of soil will drain most easily?

(d)   Which soil type drains the slowest?

(e)   Based on observation, which soil type would be the best for germinating/growing plants?

(i)                  Justify your answer.

(ii) Would you say the test was fair? YES/NO. Give reasons for your thinking.

EXPLAIN

Students will give their report of the experiment, and answer the questions based on experiment carried out.

EXTEND/ELABORATE

Students will make concluding sentences on why the soil is so important to mankind and why it should be conserved. Examine video clips of some devastation caused by soil erosion around the world. Add concluding statements to their piece, explaining what we can do to preserve/conserve the soil, and prevent soil erosion.

EVALUATE

1. Explain why it is important that soil retains (holds) only some amount of water but not too much.

2.  Read the fascinating facts below then answer the question that follows.

FACINATING FACT The richest, most fertile upper layer of soil is known as topsoil. It takes 500 years for 2.5 cm of topsoil to form.

  

 

 

3. You were just informed about this soil facts by your teacher. Use it to prepare a poster for the members of your farming community. Be sure to inform them of the fact, and why they need to preserve/conserve the soil.

3.       Use the passage and the results of the investigation to complete the activity.

 

 

NEEDS OF A CACTUS PLANT

A CACTUS IS A PLANT THAT CAN SURVIVE IN DRY, DESERT-LIKE CONDITIONS. MOST CACTI STORE MOISTURE IN THEIR STEMS AND UNLIKE MANY OTHER PLANTS, THEY ARE LESS DEPENDENT ON THE SOIL TO PROVIDE THEM WITH MOISTURE.

DESERT CACTUS MUST HAVE A VERY WELL-DRAINED SOIL FOR THEIR SURVIVAL.

 

RESULTS OF INVESTIGATION

The table shows the results of an investigation to determine how water drains through three types of soil.

Soil Type	Time taken for water to drain through soil         (minutes)	Volume of water added to soil (cm 3 )	Volume of water drained through soil           cm 3
Soil A	10	120	80
Soil B	4	120	100
Soil C	7	120	100

Order the three types , Soil A, Soil B, Soil C from most suitable to least suitable for growing a cactus plant. 

Most Suitable            ⬜              ⬜             ⬜                    Least Suitable  (2 marks)

 

4.      5.  Complete the table below by indicating if each statement is a property of the different types of soil. (page 22 Text)

Properties observed	Sand	Garden soil	Clay
There is a lot of decaying materials in it.	¡	¡	¡
It is grainy and has large particles.	¡	¡	¡
It is greyish white in colour.	¡	¡	¡
When wet and rubbed between the fingers, it feels smooth and is very sticky.	¡	¡	¡
It is moist and the particles tend to clump together.	¡	¡	¡
You can pour it easily from your hand.	¡	¡	¡