Science - Level E

Home Page	Access to other Strands & Attainment Outcomes	Skills	Materials from Earth	Energy & Forces	Living Things
			Changing materials
Level E	Learning activities & links to Target Groups (G) in Framework for Planning	Additional advice from Guide for Teachers & Managers
Target, Code & Menu
ES-E1.1	Target Menu from G18 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)	Earth in Space
explain day, month and year in terms of the relative motion of the Sun, the Earth and the Moon	record the changes in shape of the Moon over a calendar month and use models to illustrate and explain the phases use video or computer programmes to establish the difference between the 24-hour rotation and 365-day (approximate), orbit of the Earth use a datalogger to collect data about temperature and light using a tilted globe relate these measurements to seasonal changes	This is a challenging topic for pupils and teacher alike. The Moon orbits the spinning Earth that is itself in orbit round the Sun. Good evidence of these relationships comes from a solar eclipse, when Earth, Moon and Sun are aligned, with the Moon preventing sunlight from reaching us. For able pupils it is worth introducing the subject of gravitational effects on our oceans, so that when Sun and Moon pull from the same direction we get our largest tides. Similarly, the inclination of the Earth's axis can be introduced to explain seasons. There should be an appropriate emphasis on scale and pupils should be introduced to the use of light years to measure vast distances [the distance that light, travelling at 300,000 km per second (186,000 miles per second), covers in one year]. Light from the Sun takes only 8.3 minutes to reach us, representing a very short distance in terms of space.
ES-E1.2	Target Menu from G18	Earth in Space
describe the Universe in terms of stars, galaxies and black holes	use small research teams to gather information, each team to focus on one feature find a way of displaying the salient features of stars, galaxies and black holes in order to distinguish between them.	During research, other familiar terms will be encountered - planets, moons, comets, asteroids, meteorites. This might help establish scale of the much larger stars and galaxies. For black holes the emphasis is on the dead star becoming smaller and smaller yet having a constant mass. Near the surface of the star there is a corresponding increase in gravitational pull, which eventually becomes so strong that not even light can escape. A black area with no escaping light is formed.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Earth in Space	Changing materials	Energy & Forces	Living Things
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
ES-E2.1	Target Menu from G22 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Materials from Earth
describe the particulate nature of solids, liquids and gases and use this to explain their known properties	observe and offer explanations of a variety of experiments: (comparing masses of identically sized blocks of different materials, putting a small coloured crystal into cold water and into hot water, trying to fit a metal bar into a gauge before and after heating, opening a perfume bottle at a distance, heating a metal rod that has paperclips attached by petroleum jelly, trying to depress syringes filled with solid, liquid and gas) observe what happens when measured volumes of dried peas and sand are mixed and use this to explain the reduction in volume occurring when alcohol and water are mixed investigate diffusion in air, in liquid and in gel predict the effect of gas pressure (collapsing can experiment), using the particulate theory		The series of experiments should be carried out quickly. The purpose is to encourage observations and explanations. Most pupils will have incorrect ideas at this stage. They can be revisited once the particulate nature is established. The terms 'atom' and 'molecule' should be introduced with care. Particle motion is faster in a gas than in a liquid, and faster in a liquid than in a solid. Pupils find it difficult to accept that the spaces contain nothing - believing that they are occupied by air. Take particular care in explaining the pea/sand model. This subject allows for the idea that theories must be tested and that they can be used to explain the results of experiments. Models are very important in helping us to understand how nature works.
ES-E2.2	Target Menu from G28		Materials from Earth
describe what is meant by an element	heat a piece of bread and explain the result examine a range of materials (elements, rock samples, living things) to illustrate the variety of materials that exist carry out a sorting exercise to separate elements from other materials study the Periodic Table and record symbols, appearances and uses of elements use models to explain how elements are made up of only one kind of particle (atom)		Much of the bread is lost during the burning but a black solid is left - carbon. This is an example of a simple chemical called an element. It consists of atoms of only one type. When examining the range of materials it will be helpful to include some gases, e.g. chlorine. Prepare samples of hydrogen and oxygen to further illustrate the existence of elements. It may be helpful to point out that many elements are metals.
ES-E2.3	Target Menu from G28		Materials from Earth
describe how physical properties of elements are used to classify them as metals or non-metals	group research task to search for data on five elements (symbol, state at 20 °C, metal or non-metal, magnetic or not, appearance, etc.) examine a range of metals to establish their common properties demonstrate malleability compare metals with non-metals look up melting points of common metals and non-metals.		There are 84 metals and 21 non-metals. Metals are usually strong, malleable, ductile, sonorous. They shine when polished, are good conductors of heat and electricity and (except mercury) are solid at room temperatures. Non-metals tend to be brittle. They are not strong, generally have low boiling and melting points and are poor conductors.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Materials from Earth	Energy & Forces	Living Things
				Properties & uses of energy
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
ES-E3.1	Target Menu from G29 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Changing materials
give examples of simple chemical reactions, explaining them in terms of elements and compounds	use models to establish the idea of elements combining to form compounds demonstrate examples of some reactions between elements and ask them to record their observations in terms of appearance of the reactants and products to include energy release use models, diagrams and simulation software to represent the compound formed demonstrate the need for energy to break up a chemical compound by showing that water can be split into hydrogen and oxygen prepare samples of hydrogen, oxygen and carbon dioxide and demonstrate appropriate methods for testing the gas produced during chemical reactions		Classes should be introduced to chemical names and symbols of elements. Pupils should be aware that each compound has a definite composition that can be represented by a formula using these symbols. With proper attention to safety, a range of reactions can be demonstrated.
ES-E3.2	Target Menu from G22		Changing materials
describe the effect of temperature on solubility	plan and carry out a valid investigation of the effect of temperature on the solubility of salt or sugar in water investigate the effect of temperature on the dissolving rate of a range of artificial sweeteners		Pupils should account for variables. In their report they should be encouraged to refer to the particulate nature of matter and to describe what they find in terms of particle movement and spaces between particles of water. It could be noted that for some substances, solubility decreases as temperature rises.
ES-E3.3	Target Menu from G23		Changing materials
describe the use of pH to measure acidity	examine a range of acids and alkalis and discuss their characteristics investigate the effect of adding household and laboratory acids and alkalis to dyes extracted from plant material explore the range of pH of a variety of acids and alkalis		The values alone, '0_14' will be sufficient here, with '7' being neutral. The values can be used to describe strongly or weekly acidic or alkaline solutions. It is not necessary to discuss the difference between weak and strong and dilute and concentrated.
ES-E3.4	Target Menu from G23		Changing materials
describe the process of neutralisation and give some everyday applications	investigate what happens to the pH of a dilute strong alkali when a dilute strong acid is added drop by drop find out about everyday applications of neutralisation find out about the use of acids and alkalis in everyday situations investigate the differences in the acid content of a range of soft drink		Burettes, dilute acid, and conical flasks of dilute alkali with universal indicator should be available. Pupils should be aware of the salt and water products. Note that not all salts are neutral. Milk of magnesia and indigestion, treatment of garden soil, sodium bicarbonate for acid bee sting and vinegar for alkali wasp sting, hair- and skin-care are all examples.
ES-E3.5	Target Menu from G23		Changing materials
describe what happens when metals react with oxygen, water and acids	investigate reactivity of metals in oxygen, dilute hydrochloric acid and water investigate displacement reactions use secondary sources to find out about how reactivity relates to uses and sources of metals		Safety issues must be carefully considered, with judicious demonstration and use of safety goggles. The names of products should feature in this work.
ES-E3.6	Target Menu from G23		Changing materials
describe how metal elements can be extracted from compounds in the Earth's crust.	investigate the effects of electrolysis carry out electroplating experiments use secondary sources to investigate how some metals are extracted (gold, silver, copper, lead, iron and aluminium).

Home Page	Access to other Strands & Attainment Outcomes	Skills	Conversion & transfer of energy	Earth & Space	Living Things
				Changing materials
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
EF-E1.1	Target Menu from G25 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Properties & uses of energy
describe the differences between the flow of heat by conduction and convection	investigate conduction of heat in a variety of materials use a spiral of paper to demonstrate convection over a heat source and observe convection using a crystal of potassium permanganate		Conduction is explained in terms of vibrating molecules. Pupils often believe that when they touch a cold object, cold flows into their fingers, but of course the sensation is due to heat flowing out from their fingers into the cold object. This is why good conductors such as metal feel cold to the touch and why insulators, such as expanded polystyrene, feel relatively warm. Convection is explained in terms of density.
EF-E1.2	Target Menu from G25		Properties & uses of energy
give examples of everyday uses of good and poor conductors of heat	make lists of insulators of heat used in the home identify uses of good conductors of heat used in the home plan and carry out an investigation to find out what materials will keep a container of water warm for the longest time		Establish that air is a relatively poor conductor and so is often involved in insulation - in clothing, bedding and in newer foam lagging for pipes, etc. Expanded polystyrene could be mentioned, together with the associated fire hazards. Metals are used in radiators, cooking utensils, etc., because they are good conductors. This topic links with materials and their uses.
EF-E1.3	Target Menu from G24 Attractive compilation covering Light & Sight, from Kirkcaldy High School (pdf, 14 pages, 1.03 Mb)		Properties & uses of energy
explain the effect of a prism on white light	use a slide projector to cast a large spectrum on a wall and identify the colours and the order in which they appear explore and record the images seen in a prism challenge pupils to find out how the coloured rays produced by a prism can be re-mixed		The rainbow colours always appear in the same order - ROYGBIV (VIBGYOR is easier to remember!). The glass (or plastic) of the prism alters the angle of the light rays passing through. This is called refraction. Each different colour of light is refracted by different amounts, so the white light is split up into its constituent colours.
EF-E1.4	Target Menu from G24 Attractive compilation covering Light & Sight, from Kirkcaldy High School (pdf, 14 pages, 1.03 Mb)		Properties & uses of energy
describe what happens when light passes through different materials	carry out a range of activities to establish the idea that light travels in straight lines sort a range of materials into opaque, transparent and translucent by shining light from a ray box on to them measure the amount of light (using a light sensor) that is reflected or transmitted through the different materials		Light travels in straight lines. It is bent (refracted) as it passes into and out of glass. The investigation lends itself to measurement of angles and the collection of more quantitative data. The ideas of reflection, transmission and absorption should be explored.
EF-E1.5	Target Menu from G24 Attractive compilation covering Particles & Waves, from Kirkcaldy High School (pdf, 9 pages, 1.53 Mb)		Properties & uses of energy
explain what happens when sound passes through different materials	investigate the ability of sound to pass through a vacuum explore the transmission of sound through liquid and through solid investigate the effect of soundproofing carry out a number of surveys on noise pollution in the classroom, school and street from personal stereos analyse and evaluate information on hearing impairment		Hang an electric bell inside a jar connected to a vacuum pump and listen for sound before and after evacuating the jar. This can be used to establish the need for particles to transmit vibrations. A pencil can be used to listen to the sound, e.g., of a clockwork timer. Plastic foam, egg boxes and newspapers can all be used to reduce noise. Teacher should be aware of the need to be sensitive to individual pupils and their families.
EF-E1.6	Target Menu from G30		Properties & uses of energy
	construct a circuit with one bulb, then find a way of adding two more bulbs without causing the brightness to dim construct a circuit with two bulbs that can be switched on or off independently discuss and explore the advantages and uses of parallel and series circuits		Before arriving at the formality of constructing circuits in parallel from diagrams it is worth allowing pupils to play with circuits to try to solve these problems. Thinking investigators might raise questions about the effects on battery life. The point should be made that all household appliances are connected in parallel.
construct a parallel circuit, following diagrams
EF-E1.7	Target Menu from G30		Properties & uses of energy
use the terms 'voltage', 'current' and 'resistance' in the context of simple series circuits	use an ammeter to investigate current flow and use a voltmeter to investigate voltage construct a variety of parallel circuits and test predictions about the current at various points investigate which circuit components allow the greatest current to pass and which offer the greatest resistance to the flow of the current demonstrate the effect of increasing current on a short length of steel wool discuss the role of fuses in electrical safety.		Pupils should be familiar with the units 'amperes' and 'volts'. Voltage may be explained as an electrical force pushing electricity around a circuit. Large voltage causes a large current. To double current we double the voltage (if the resistance does not change). A thin wire has more resistance than a thick one. The electrical resistance of a wire can produce a heating effect.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Properties & uses of energy	Force & their effects	Earth & Space	Living Things
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
EF-E2.1	Target Menu from G19 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Conversion & transfer of energy
describe some examples of the interconversion of potential and kinetic energy	investigate the source of energy in a selection of wind-up toys		Pupils should discover that each toy has a mechanism that allows the movement of 'winding-up' to store energy that in turn can be released to move the toy. Movement energy (kinetic) ->stored energy (potential) -> movement (kinetic). The toy has the potential for movement when wound up. The energy a toy has because it is moving is called 'kinetic' energy.
EF-E2.2	Target Menu from G19		Conversion & transfer of energy
give some examples of chemical energy changes	find out what happens when things burn discuss flammable and non-flammable materials with regard to safety in the home collect information on the energy content of a range of foodstuffs		Candles, paper, sugar and magnesium can be investigated, with proper attention to safety. Refer to labelling on furnishings and relate to safety. Many teachers will wish to introduce energy units at this point though there is no formal requirement for this at Level E.
EF-E2.3	Target Menu from G19		Conversion & transfer of energy
explain the difference between renewable and non-renewable energy resources	debate the advantages and disadvantages of setting up a wind farm in the vicinity of the school visit a wind farm or hydroelectric scheme discuss how pupils can contribute to the conservation of fuel supplies.		The finite nature of coal, gas and oil resources should be stressed and the sustainability of hydroelectric schemes, wind power and solar power emphasised. Pupils should be helped to visualise a world without oil and the efforts that must be made to provide alternative energy sources. Responsibilities of individuals and communities can be considered, including 'not in my backyard' (NIMBY) objections to alternative developments.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Conversion & transfer of energy	Earth & Space	Living Things
					Variety & characteristic features
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
EF-E3.1	Target Menu from G31 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Forces & their effects
describe the effects of balanced and unbalanced forces	use two spring balances to pull in opposite directions use a simple model of a see-saw to investigate relationships between opposing forces weigh a series of objects suspended in air and then suspended in water discuss balanced and unbalanced forces on moving and on stationary objects to create explanatory diagrams using arrows to show the direction and scale of the forces involved		The readings on both balances indicate that the two forces are equal - Newton's Third Law of Motion (action force and reaction force are equal and opposite). The force x distance from the pivot, when the see-saw is balanced, is equal on both sides. If there were no friction, a trolley pushed in a certain direction would speed up and would then keep going at a constant speed once it was released. Pupils could be encouraged to draw a diagram of a car with the engine thrusting it forward so that the unbalanced force in the direction of movement results in the car speeding up. A block of wood on a table is stationary, with the downward force (weight) of the block being equal to the upward push of the table.
EF-E3.2	Target Menu from G31		Forces & their effects
explain how gravity on other planets and the Moon affects the weight of an object	find out which of the planets of the Solar System have the strongest and the weakest 'gravitational fields' discuss the gravitational aspects of a manned moon-landing by considering each stage of the flight research the effects of taking everyday objects to the Moon.		The larger the mass of the planet, the greater its gravitational force. Thus Jupiter has the greatest gravity, Mars the least. The Moon has a gravity about one sixth that of Earth. The mass of an object on different planets remains the same, i.e. its amount of matter does not change. However, the effect of gravity on this mass produces the force that we call its weight. As the gravity varies, so too does the weight.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Processes of life	Earth & Space	Energy & Forces
					Force & their effects
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
LT-E1.1	Target Menu from G32 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Variety & characteristic features
give the main distinguishing features of microorganisms	use secondary sources to research microorganisms and their role in disease, decay and food production examine examples of the main groups of microorganisms under the microscope or using bioviewers, e.g. bacteria, yeast, fungi grow fungi on bread sealed in petri dishes. Measure growth over a period of time make simple yeast dough and observe and measure the increase in volume in a variety of conditions		The culture of microorganisms in schools requires that a teacher is trained in aseptic techniques and is able to carry out the procedures involved and the disposal safely. The common features centre on microscopic size and on the rapid rate of multiplication. They also require similar culture techniques. The dependence of viruses on living cells of other organisms is linked to their disease-causing characteristic.
LT-E1.2	Target Menu from G21		Variety & characteristic features
create and use keys to identify living things	use published keys to identify a wide range of organisms, both plants and animals use computer programs to identify organisms produce simple keys to identify given groups of shells from a beach, leaves from trees, birds around the school, house plants from around the school		Keys should be of both branched and paired statement types. The decision points in the keys should not be made too difficult and should be made on the basis of readily observable external features. The keys should also be selected to avoid unnecessarily technical language. The value of diagrams in keys this stage cannot be overemphasised. Pupils use both types of keys with ease but branching keys are easier to create than paired statement keys and should be attempted first. Many pupils will need practice in the intermediate step of converting a branched key into a paired statement key before attempting a paired-statement key alone. Keys should be made from observing living things rather than from pictures.
LT-E1.3	Target Menu from G27		Variety & characteristic features
give examples of inherited and environmental causes of variation	group work to make collections of pictures of particular types of familiar organisms, e.g. people, cats, dogs, roses, cabbages discussion or investigation of ways in which individuals in each group are similar or different to others count and record the number of seeds in the fruit of flowering plants, e.g. peas in a pod, pips in apples or oranges, or 'petals' on lawn daisies measure and record variable features that occur in the group of pupils and discuss which are the result of inherited characteristics and which are due to environmental factors, e.g. tongue-rolling ability, ear lobes attached or unattached, left- or right-handedness and height, hand span, foot length add to or create a database to store information about features carry out an investigation into the variation in growth of seedlings such as cress, peas or beans.		Discontinuous variation arises from inherited characteristics. An organism either shows a characteristic or it does not. In humans examples include tongue rolling, left-handedness, blood grouping, and ear lobes. Eye colour is generally included in this group but can be confusing since a range of colours exists. The presentation of the findings will be a bar graph as the horizontal axis label will be descriptive and not numerical. Continuous variation arises from the action of environmental factors and gives a smooth grading between two extremes with the majority of individuals being somewhere towards the centre (height, leaf length, etc.). Observations should be systematic and involve measurement; the graphical presentation will be in the form of a histogram. Sensitivity to issues relating to parenthood is needed when talking about inheritance. Teachers may prefer to use fictional characters for this work. It is important to establish that some variation, e.g. height, may be a result of both inherited and environmental factors.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Variety & characteristic features	Interaction of living things with their environment	Earth & Space	Energy & Forces
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
LT-E2.1	Target Menu from G27 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		The Processes of Life
identify and give the functions of the main structures found in plant and animal cells	examine pictures or three-dimensional models of a range of cell types from animals and plants, or prepare slides of typical plant and animal cells and identify cell membrane, cytoplasm and nucleus identify the cell wall and central vacuole in plant cells and the presence of chloroplasts design and make 'junk' models of cells and discuss selection of materials for each cell part make drawings of cells and describe the function of each cell structure		Pupils should know that living things are composed of many different types of cells that perform different functions. They should also know the basic structure and function of typical plant and animal cells and be aware of similarities and differences. They should be aware of how similar cells are grouped together to form tissues. The care and use of microscopes will be an essential component of this part of the course. Pupils will need to practice using a microscope and in preparing simple slides including staining material. Current restrictions on which material can be safely used in schools should be observed.
LT-E2.2	Target Menu from G17		The Processes of Life
identify, name and give the functions of the main organs of the human reproductive system	use diagrams and models and view video material label male and female parts on diagrams and add function of each part		Programmes of delivery in primary and secondary schools will determine when this topic is taught and if it is integrated with work at lower levels. The emphasis should be on processes with names of parts given in a logical sequence to promote understanding of the processes involved in human reproduction (intercourse, fertilisation, menstruation, pregnancy to include the role of the placenta, umbilical cord, amnion and amniotic fluid).
LT-E2.3	Target Menu from G26		The Processes of Life
identify the raw materials, conditions and products of photosynthesis	view and discuss video material relating to plants and photosynthesis formulate hypotheses about the factors that affect the ability of plants to carry out photosynthesis and test hypotheses experimentally demonstrate oxygen production using a pondweed use simulation software to investigate the effect of changing one factor in photosynthesis investigations discuss and debate (using role play) the importance of green plants to the environment.		Pupils should be able to make suggestions about raw materials and conditions. They should be helped to convert their ideas into testable hypotheses and develop for themselves the photosynthesis word equation. The method for testing green leaves for starch will have to be introduced and safety procedures adhered to.

Home Page	Access to other Strands & Attainment Outcomes	Skills	Processes of life	Earth & Space	Energy & Forces
Level E	Learning activities & links to Target Groups (G) in Framework for Planning		Additional advice from Guide for Teachers & Managers
Target, Code & Menu
LT-E3.1	Target Menu from G26 Attractive compilation covering Level E, from Kirkcaldy High School (pdf, 10 pages, 1.63 Mb)		Interaction of living things with their environment
construct and interpret simple food webs and make predictions of the consequences of change	construct simple food chains and webs based on observations of local habitats and other stimulus material interpret data from prepared food webs and make predictions about the effects of altering the population of a member of the web use computer simulation software involving population dynamics in ecosystems. Predict and test the effects of altering one factor		Food webs are diagrams that illustrate the feeding relationships of organisms in a habitat. Each web is composed of a number of interconnected food chains. Pupils should examine simple prepared webs before attempting to construct their own for a known habitat such as a pond, garden, woodland, or rock pool. Encourage pupils to consider what evidence can be used to find out what animals eat, e.g. owl pellets, bird droppings, teeth marks, remains found near lairs or nests and observations of feeding habits. An understanding of the effects of altering a food web should help pupils to understand better the potential effects of human activity on the environment.
LT-E3.2	Target Menu from G26		Interaction of living things with their environment
describe examples of competition between plants and between animals	investigate the effect on seedling growth of sowing seeds at different densities investigate dispersal of seeds view video material and access resources to find out about the effect of the introduction of the grey squirrel in Britain carry out a survey of weeds growing, for example, in a lawn, wasteland or crop field discuss/research the effect of selective weedkillers on specific food webs.		In every ecosystem there is a continual struggle for survival between organisms of the same species and between different species. Competition for space, light and food might have short-term effects on survival. Successful breeding ensures species survival. Competition in plants is usually for light and moisture. Seed dispersal reduces intraspecific competition and leads to colonisation of new areas. The emphasis here is on the physical factors which affect the distribution of organisms in different habitats, e.g. light, temperature, oxygen availability.
LT-E3.3	Target Menu from G27		Interaction of living things with their environment
give examples of physical factors that affect the distribution of living things	examine a range of common plants and identify an important environmental factor that affects their distribution investigate the effect of moisture level in different soils and the variety and abundance of plants.