B Barber
Science Coordinator

Science

"Water Show" (Middle)
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Equipment:

• flash cards of animals that live in water: algae, fish, "lions", bacteria etc.
• 2 beakers, water, 2 blocks of ice, methylated spirits.
• 5 beakers, water, oil, food colouring, salt, sugar etc.
• flash cards - washing hands, different types of drinks, gardening, hydroelectricity, beach, showers, washing cars, toilets, swimming pools, cooking.
• Map of house.
• Water cycle demonstration apparatus; flood light, ice.
• water in a beaker.
• kettle, water & thermometer.
• beaker, cold water and crushed ice.
• electronic balance, measuring cylinder, 4 beakers with equal amounts of water, oil, methylated spirits, honey etc.
• Water from a beaker onto your hands.
• Soil, block of wood? water.
• Two trays of pond water; 10-15 magnifiying glasses; 2 stereo-microscopes and petri dishes.
• Electrostatic rod or plastic ruler, piece of wool or a jumper, plastic lemonade bottle with a hole near bottom, water.
• Testing Drinking Water:
  • filter paper, funnel, conical flask;
  • gritty water; oil, water and chloroform;
  • Universal indicator or cabbage water, 3 beakers and sample food acids/bases;
  • silver nitrate and chlorinated water;
  • barium chloride and sulphate water.
  • conductivity meter?

Demonstrations:

Task	Experiment	Method	Equipment	Concepts
1	Ice in Water	Place a cube of ice in water and alcohol and compare flotation	2 beakers, water, 2 blocks of ice, methylated spirits.	Ice is less dense than water but more dense than alcohol.
2	What dissolves in water?	Place oil, food colouring, rock, sugar, salt and other substances in a beaker of water.	5 beakers, water, oil, food colouring, salt, sugar etc.	Only certain substances can dissolve in water. Can you suggest others?
3	What do we use water for?	Flash cards of washing hands, different types of drinks, gardening, hydroelectricity, beach, showers, washing cars, toilets, swimming pools, cooking.	Flash cards.	When do we use water. At home? At school?
4	What uses the most water?	Place these in order (most use to least use)... - Gardens - Toilet & Bathroom - Laundry - Kitchen	Bird's eye view of a house - see below.	Which room uses the most water in the house?
6	How does the water cycle work?	Demonstrate how water evaporates from the sea, condenses on hills, flows into the sea and then evaporates again.	Water cycle demonstration apparatus; flood light, ice.	Demonstrating the water cycle and how we never will run out of it. Talk about salt water and fresh water and how fresh water from river systems turns into salt water and through evaporation changes back into fresh water.
7	Properties of water - general features	Describe water - colourless, odourless, tasteless (?), cold, movement (viscous).	water in a beaker	How can we describe water? What does it look like? How does it smell? How does it flow? Discuss states of matter - see below.
9	Properties of water - boiling point	Use a kettle and thermometer to measure the boiling point of hot water.	kettle, water & thermometer.	Talk about 60 degrees of higher can burn like fire - very dangerous.
10	Properties of water - melting point	Use crushed ice in a beaker of cold water to measure the melting point of water.	beaker, cold water and crushed ice.	Talk about 0 degrees celcius and the nature of ice to expand when frozen - broken bottles in fridge and insulating life under the sea during the ice age.
11	Properties of water - density	Use beakers with equal amounts of water, oil, methylated spirits or any other liquid in them to compare densities - the heavier liquid will be more dense.	electronic balance, measuring cylinder, 4 beakers with equal amounts of water, oil, methylated spirits, honey etc.	Compare each and see which is heavier for the same volume.
12	Properties of water - heat capacity	Put water and your hands and shake them. What do you feel? Cold?	Water from a beaker onto your hands.	Evaporating water from our skin can take away a lot of heat out of our bodies. When is this useful? During summer when we are hot. We use water to keep our cars cool in the radiator, we also perspire to keep ourselves cool.
13	How do we store large amounts of water?	Go outside and create a channel of water blocked by a dam in the ground.	Soil, block of wood? water	Try to construct a dam outside and observe how it works.
14	Water Bug Detective Guide	Use the Water Bug Detective Guide to identify good quality water.	Two trays of pond water; 10-15 magnifiying glasses; 2 stereo-microscopes and petri dishes.	Observe pondlife.
15	Taste Testing	Get students to sample 4 different clear liquids to identify them.	flat lemonade, water, sugar in water, salty water.	They are all colourless and odourless but have different chemicals in them.
16	Sparky water	Puncture a small hole towards the bottom of a plastic lemonade container. Fill it with water and leave the lid off and let the water fall through the hole in a steady stream. Charge by rubbing a piece of wool over an electrostatic rods (or plastic ruler) and place it near the stream of water and watch it bend!	Electrostatic rod or plastic ruler, piece of wool or a jumper, plastic lemonade bottle with a hole near bottom, water.	Water is a molecule with a positive and negative end. Therefore when a charged rod with static electricity of it will make the stream of water bend towards or away just like a magnet.
17	Testing Water for Drinking The following table describes how to test for various pollutants in drinking water: Pollutant How to test Observation Suspended solids Filter sample with filter paper: Pour some of the liquid through a filter that has some filter paper in the top. Is there any residue? Solids will be trapped by filter paper. Oil or grease Shake with some chloroform, separate the chloroform by filtering and allow it to evaporate. Any residue? Oil and grease will be visible in the container. Soluble (dissolveable) solids Filter some sample liquid, extract oil and grease and evaporate sample in container. Any residue? Solid left in container. Acid or base? Add a few drops of Universal indicator to the sample or use boiled red cabbage liquid (a natural indicator). Use 0.1M? HCl and NaOH to add to 3 beakers of water. For universal indicator, if acid it will go red-yellow; if base it will go blue and neutral green. Chloride Add a few drops of silver nitrate solution to a sample. A solid will form. Sulphate Add a few drops of barium chloride to a sample. A solid will form.

1. Program notes:

Activity:

• Boiling point of Water
• Making a Well
• Solar Still
• Testing for Pollution
• High and Low Tide
• Oil and Water
• Water Well
• Evaporation
• Floating Objects
• Ice in Alcohol

Facts:

• Ice
• Survival without Water

Information:

Sometimes rivers and streams can be polluted. Scientists test the water of these streams to see if the water is safe for humans as well as other animal life in the streams. What type of life lives near your wetlands? Have you seen these? Or these? [Flashcards]

A huge 75% of water covers the Earth's surface including oceans, rivers and inland lakes. We use water for at home, in irrigation, in industry, for disposing of waste and for drinking. The enormous amount of water that is used never runs out since the cycling of water from evaporation from the Earth's surface forming clouds and then rain completes the cycle. The water cycle involves the evaporation of water on the Earth's surface by the Sun from lakes, rivers and oceans. Water vapour then rises into the air and starts to crystallise to form visible clouds. The droplets then form rain and fall back to the Earth and make their way through rivers, streams or underwater movement to the ocean again.

Water is a very important resource which is essential to all life. Human blood is made up of 80% water and as a result we must drink close to 1 and 2 litres of water a day. The main form of water supply comes from man-made dams, rivers and lakes or underground water such as wells. Catchment areas collect water that runs off from nearby hills and mountains and into dams or lakes. Groundwater comes from rain that soaks into the ground. It fills up small passages between sand, rock and plant matter making up the soil. Some soils such as clay does not allow water through it. Water cannot travel downwards indefinitely. It eventually meets with a layer of impervious rock. Water then begins to fill from there upwards to a level called the water table. The soil within the water table is said to be saturated.

Groundwater from a well or bore contains a large amount of minerals, largely magnesium and calcium salts. This type of water is called heavy water making it difficult to lather in this water. Most of the water in the world is in the ocean and is unsuitable for drinking because of the high levels of salt. The removal of salt is called desalination. Two methods of desalination include evaporation and distillation. Evaporation will convert water into steam which can then be collected, cooled again and it then condenses back to water. The salt in the original water sample does not evaporate in the same way and remains behind. Distillation requires distillation apparatus that effectively boils salt water and evaporates pure water which is then collected in a cooling condenser tube and drains into another container.

What is Matter? Everything around us is made up of matter. The desk, your clothes, the air you breathe ... everything. Any matter can we weighed. It is said to have mass. Matter also takes up space. The amount of space it takes up is called its volume. Matter is classified into one of three types: solids, liquids or gases.

Solids, liquids and Gases: Solids can be tapped; liquids can be poured; and gases float. All matter is one of the three physical states: solid, liquid and gas. Its structure depends on temperature. All substances start as solids at the very lowest possible temperature, absolute zero (-273°C) and go through changes of state as they are heated. As a solid is heated, it will generally melt to become a liquid, and then boil to form a gas. Solids have a definite shape. Liquids take up the same volume within shape of its container even though the shape may change. Gases also do the same except they will always take up the same volume as that of the container. Gases can therefore be squeezed into a smaller container. Solids and liquids cannot.

Distributing water: Water for towns is first pumped into small local reservoirs or water towers. They are built at higher elevation in order to be used to supply the immediate area with its water needs.

How we use water? Water is used for drinking, for work, recreation, in our gardens and homes, in agriculture, in industry, in transport and power generation. In Australia the percentages of water use are approximately ...

Domestic uses of water: A large proportion of water usage is at home. Washing clothes and ourselves, flushing toilets and watering gardens use the most water. The amount of water usage on average is as follows ...

Irrigation

Irrigation is the watering of plants by artificial means. The most important irrigation is supplying water to grow food crops such as cereals, vegetables and fruit. In areas where there is suitable soil but not enough rainfall, irrigation from a steady stream of water from dams, canals and systems of pipes bring water to those areas. Many areas of New South Wales have quite extensive irrigation systems set up.

Storing of Water

In Australia, we heavily depend on rivers for our water supply. Since water makes up 70% of most living things it is very important. We cannot survive is we lose more than 20% of our normal water content. The storing of water is therefore very important in above-ground or underground sources. Man-made lakes or dams, springs or reservoirs. We can treat ground-water that may contain large amounts of minerals. Hard water is the term for this and lathering of soap in such water is impossible. Calcium and magnesium is the main mineral contaminating this water.

Often a chemical called zeolite is added to remove much of the magnesium and calcium, replacing it with sodium. Many towns and cities support their population with ground-water from nearby rivers and lakes. Other cities may need to pipe their water into town.

Salinated water is also a nuisance making water undrinkable. Often desalination is required to remove much of the dissolved salt. When water is boiled it changes to steam. This steam is collected, cooled and condensed to form pure water leaving behind the salt.

Water & Electricity Generation

Moving water contains a lot of energy that can be used by turbines to provide electricity for nearby townships. The process of hydroelectricity starts with water stored in dams to fall through large pipes onto water turbines. The moving water rotates the turbines at high speeds generating electricity. The Snowy Mountain Scheme is one of the largest power and irrigation schemes in the world providing electricity to New South Wales, Victoria and Canberra.

Transport

River transport or goods, people and services is very common in countries with an extensive river system throughout. Sea transport of goods and supplies has occurred for many centuries even though now a greater proportion of transport is by air.

Recreation

People enjoy going to the beach during summer, yachting and swimming.

Industry & Mining

Water is the main chemical used in industry than any other chemical. It is used for a large variety of purposes from manufacturing to refining petrol or making beer. Most water in industry is used for cooling such as sheet metal plants or in the mining industry for processing nickel or removing dry clay from gold deposits. The extensive use of water can do damage to plant and animal life and upset the balance of the environment.

Water Pollution

Some Common Drinking Water Contaminants

Drinking water is very important. Water from rivers and dams to be used for drinking are first cleaned by filtration and sedimentation. Some common types of bacteria can help eat dirt particles in water; sand and gravel can also be used to filter water. Water containing dissolved solids, such as clay or sand, are allowed to drain through tanks containing layers or sand and gravel. The very fine particles that cannot be removed by filtration are made to join together by adding special chemicals such as aluminium sulphate.

After the water has been cleaned it is disinfected with a small amount of chlorine to kill any bacteria: this process is called chlorination. Other minerals such as fluoride are added for health reasons through fluoridation. Many poisonous pollutants cannot be removed in this way. The only water to have safe drinking water is to prevent the poisons from getting there is the first place. For this reason, catchments areas have restricted access.

Treatment of Sewage

The term sewage is the waste and water mixture that humans out down sinks and drains in the kitchen, laundry, bathroom, toilet and in industrial processes. Sewerage is the word used to describe the network of pipes into which the sewage goes. Connections to the sewerage system begin with the plug hole and an "S" bend which acts as a water lock, preventing smells further down the network from your home. Some homes are connected to a septic tank, where sewage breaks down due to the action of bacteria and is released into the soil, leaving a thick sludge in the tank which must be removed periodically. It musy remain chemical free, since the chemicals can kill the bacteria that is doing the process.

Sewerage treatment plants involve the activated sludge process. Sewage entering the plant have larger objects removed firstly. It then flows into an aeration tank, where blowers pump air into the tank to feed bacteria which helps break down the sewage. At the Werribee sewage treatment plant, gas produced by bacteria as they break down is collected and used to power turbines for the aerators and some of the power is sold to the electricity company. Chemicals are also added to convert dissolved wastes into solids which then fall to the bottom of the tank. The next stage is the settling tank where bacteria and other solids settle to the bottom in a thick sludge. Some of the bacteria may be returned to the aeration tank to help break down sewage. The sewage then passes into pebble bed filters where suspended solids are removed. UV light or chorination is used to disinfect the sewage before it is released into the ocean. The sludge is removed and air dried before being stored for several years, after which some of it may be sold for use in soil and fertilizer products.

Water Quality

Background knowledge: Fresh water is our most valued and sought-after renewable resource. Clearing and subsequent land uses, urban developments and changes to the natural flow of our rivers have affected the physical, biological and chemical characteristics of fresh water and contributed considerable quantities of sediment, salts, nutrients and toxic chemicals to our waterways and wetlands.

Good-quality water is important, since poor-quality water can affect human health, harm wildlife and limit food production. Most monitoring programs involve surveys of stream habitat, macro-invertebrates and algae as well as tests to monitor the physical and chemical conditions of the water. The entire area from which a stream or river receives its water, from both surface and sub-surface or groundwater run-off, is called a catchment.

When it rains, the water drains naturally to the lowest point on the land, forming into small creeks that feed into larger streams and rivers as they run downhill.

To monitor water quality:

Aquatic environment:
Food: Riparian vegetation provides a range of food for animals living in the water. This food mainly comes in the form of falling leaves, branches and logs. Branches and logs also hold decomposing vegetation long enough for it to be used by animals in the stream. Insects attracted to the riparian zone become part of the food supply by either falling in the water or laying eggs.

Protection: Within the stream, many animals depend upon the logs and branches that fall as a source of shelter. These larger forms of debris also affect the flow of the water and thus provide better living conditions for some of the animals. Shade from the overhanging trees lowers water temperatures, improving conditions for plants and animals. By reducing the light entering the water body there is less chance for imbalance to occur with respect to the amount of plant growth in the water.

Experiments:

1. `The pole technique': To collect water from wide or deep streams, use a plastic bottle taped securely to a long pole such as a broomstick. Use this pole to collect your sample from a point as far from the bank as you can safely reach. Alternatively, attach a small container such as a plastic yoghurt container to a fishing rod and lower it into the stream from the bank.

2. Use Distilled water or deionised water: You can use either distilled water or deionised water for these chemical tests, although the instructions use the term distilled water. Both distilled and deionised water are available from chemical suppliers and supermarkets; deionised water is the cheaper of the two.

3. Dissolved Oxygen: What is it?

Dissolved oxygen (DO) is the small amount of oxygen that is dissolved in the water. This oxygen is vital to fish, other aquatic animals, micro-organisms and plants which depend upon it for the process of respiration, i.e. to 'breathe'. Maintenance of healthy and diverse aquatic ecosystems depends on oxygen levels being maintained at consistently high levels. Reductions in DO levels result in loss of the more sensitive species. At very low DO levels, only very few species may be present.

The DO level is also a useful indicator of water quality. It can tell us how a water body is behaving and it can indicate the presence of certain pollutants, particularly organic matter (matter that has come from plants and animals e.g. fallen leaves, animal manure, sewage effluent). One accurate test for dissolved oxygen is to use a wet chemical preparation called the Modified Winkler Titration Method.

Should be about 70% in the wetlands.

4. Temperature: What is it?

We all know what temperature is, but its significance with regard to water quality is not quite so straight forward since temperature influences many other characteristics of water. Temperature is measured in degrees Celsius (°C).

Many of the physical, biological, and chemical characteristics of a river are directly affected by temperature.

· The temperature of the water influences the amount of oxygen that can be dissolved in the water.
· Riparian vegetation keeps waters cool.
· Temperature influences the rate of photosynthesis by algae and large water plants.
· Temperature influences the sensitivity of organisms to toxic wastes, parasites and diseases.
· The temperature of water varies depending on the water body.

Maximum recommended increase in the natural temperature of any inland or marine waters is 2°C.

5. Turbidity (Suspended solids)

As erosion occurs within a catchment tiny particles of clays, silts or small organic particles are washed into water bodies. Industrial wastes and sewage also can contribute particles. These tiny particles can be held by the water and are termed suspended solids. The faster the water is moving the more suspended solids it can carry.

Suspended solids can be measured in milligrams per litre (mg/L) by filtering the water and weighing the dried residue.

Turbidity is the result of suspended solids and is a relative measure of the clarity of water: the greater the turbidity, the murkier the water. Increases in turbidity reduce the transmission of light.

· Increased turbidity silts up stream habitats.
· The fine particles settle in downstream areas and make the bottom habitat unsuitable for many animals.
· Increased turbidity reduces light penetration through the water
· This reduces the amount of light for plant growth and thus limits growth of beneficial aquatic plants.
· Increased turbidity affects pollutants.

The most effective method of testing for turbidity is by using a turbidity tube. For this test you simply collect water and pour into the tube until you cannot see the markings on the bottom. Record the reading from the side of the tube. If possible, stand the tube on a white tile. These tubes are handy because they are cheap and simple to use. A seechi disc can also be used. For greater accuracy use a nephelometer. This instrument determines the scattering of light and is measured in standard Nephelometric Turbidity Units (NTU).

Seasonal mean turbidity and suspended solids levels must not change by more than 10%.

6. Salinity:

Salinity is simply a measure of the amount of salt dissolved in the water. Salts are substances such as common table salt (sodium chloride, NaCl), limestone (calcium carbonate, CaCO3) and many others. They are picked up by the water as it runs over and through the rocks and soils of the catchment. Low levels of these salts are vital to the growth of aquatic plants and animals but high levels can cause problems for aquatic life and for human uses such as crop irrigation.

There are two ways to measure salinity: using total dissolved solids (TDS) or electrical conductivity (EC).

· Salinity is determined by the geology and soils of the catchment.
· Salinity varies with flow.
· Aquatic plants and animals need the natural salts contained in waters for growth.
· Human induced changes to catchments can affect the salinity of runoff water.

Fresh waters should not exceed 1,000 mg/L. Typical sea water is 35,000 mg/L. Drinking water should be less than 1,000 mg/L.

7. pH testing:

pH is a measure of how acid or alkaline the water is, on a scale of 1-14. It is a measure of the hydrogen ion (H+) concentration. Water (H2O) contains both H+ and OH- ions. Pure distilled water contains equal numbers of H+ and OH- ions and is considered neutral (pH 7). Because pH is a logarithmic scale, every unit change (for example from 5 to 4) represents a ten-fold increase in acidity.

The pH of fresh water usually lies in the range 6.5 to 8.2, although wide variations can occur because of catchment geology. It can also be affected by a range of factors including industrial run-off and sewage.

Animals and plants in streams are adapted to certain ranges of pH. Even under natural conditions, the animal and plant communities of acid streams contain many different species to those in alkaline streams. An increase or decrease in pH outside the normal range of a water body will cause sequential loss of the species depending on their sensitivity. Extremely high or low pH values will lead to the death of all aquatic life, so to retain a healthy diversity of life, pH must be kept within the range of natural variation for the water in question.

· The pH of natural waters is largely determined by the geology and soils of the catchment.
· Increasing salinity causes increase in pH.
· The photosynthetic activities of plants and algae can cause significant variations in pH.

Freshwaters pH values of more than 0.5 units outside the natural range should be investigated. Less than 6.5 may be corrosive. More than 8 progressively decreases efficiency of chlorination. More than 8.5 may cause scale and taste problems.

Litmus paper: Test for pH of water.

8. Nutrients:

Phosphorus and nitrogen are both nutrients that occur naturally in water. They appear to be the most important nutrients in the eutrophication of water bodies.

Nutrients are also contained in stream sediments. If these are suspended they can maintain eutrophic (increased plant growth) conditions for many years. Many factors influence how much nutrient in waterways is dissolved (soluble) or attached to particles (particulate). Some of these factors are listed.

· Environmental factors
· Catchment characteristics
· Management practices

9. Phosphorus:

Phosphorus is a mineral nutrient which is essential for all forms of life. It plays a major role in energy transfer processes in the cells of living organisms. Phosphorus has the chemical symbol, P. Phosphorus occurs naturally at low concentrations in surface waters and is an essential part of the food chain. Under these conditions it is derived from processes such as the weathering of rocks and the decom-position of leaf litter or other organic matter.

Phosphorus concentrations very considerably under natural conditions, depending on factors such as local geology, soil types and seasonal conditions. Concentrations can be expected to be much higher when wet weather conditions generate runoff and stream flows are high. It is important to consider stream flow rates and recent weather conditions when interpreting phosphorus results. In natural waters, phosphorus occurs in several different forms. These can be broadly categorised as dissolved forms and particulate forms. In the dissolved form phosphorus occurs as phosphates (phosphates are phosphorus bound to oxygen, e.g. PO4). These may be present as simple `reactive phosphate' or as more complex forms of phosphate. Particulate forms include phosphorus bound to clay minerals suspended in the water (for example, from eroded soil) and biological forms such as algae.

The delicate balance of an ecosystem can be upset when phosphorus concentrations become too high. Resulting problems can include algal blooms, excessive growth of aquatic weeds and loss of species diversity. High concentrations of phosphorus in water bodies are often the result of human activities. Rural and urban runoff, sewage effluent and industrial discharges can all contain large amounts of phosphorus from fertilisers, eroded soil, detergents and plant and animal wastes. Under certain conditions, high phosphorus concentrations in water may come from bottom sediments, where they may have accumulated over many years.

Total P (mg/L) in rivers & streams must be between 0.01 - 0.100. In lakes & reservoirs between 0.005 - 0.050.