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CCSLC INTEGRATED SCIENCE – Module 2

WATER

The water cycle shows how water moves continuously from one place to another on earth. The Sun makes the water evaporate and then the process of precipitation returns that water from the clouds to the earth in the form of rain, sleet, hail and snow. The water that falls to the land then evaporates again and the cycle repeats. 1. Complete a diagram of the water cycle (see pg. 34 CCSLC text book).

DIAGRAM SHOWING THE WATER CYCLE

2. Label the diagram below to show where, on earth, each change of state occurs in the water cycle. How do these changes in state influence the seasons?

DIAGRAM SHOWING THE CHANGES OF STATE OF WATER

3. Use the words below to complete the passage on the uses of water.

transportation live washing blood solvent

Water is very important for the cells in our body, our …………………… is composed of water, it is important for

drinking, ………………………… clothes, dissolving substances, cooling machines in industrial plants and for some

animals to not only drink but …………………….. in also. Therefore, water is an ideal habitat for aquatic life, a great

……………………….. for humans and an excellent means of ………………….………… for ships, blood in our bodies etc.

Water has the following physical properties: odourless, colourless, tasteless, high surface tension, boiling point is 100 oC and melting point is 0 oC. Water is cohesive and adhesive. Water is also used as a solvent for many substances. Substances such as sugar in juices, nutrients in the blood and gases in the lungs are all dissolved in water. A solvent is a liquid used to dissolve other substances.

3. What affects how quickly salt dissolves in water?Think of as many variables as you can that might affect how quickly salt dissolves in water.Choose one of these variables to investigate. Make a prediction and plan your investigation.

Water pollution is a great problem, where substances like sewage, detergents from large scale industries and fertilisers from farms often run into rivers, lakes etc. This promotes the growth of unwanted algae, eventually resulting in the death of aquatic animals. The oxygen that is dissolved in the water is used up by the algae and microorganisms which feed on the algae. This means the animals and plants that depend on the oxygen in the water for survival die.

Thermal pollution, where the water is used to cool down machines at industrial plants and then returned to the river at high temperatures may cause the death of vital organisms to our ecosystem and thereby disrupt the balance of life in the aquatic environment.

Heavy rainfall, deforestation etc. may cause the silt or top soil to flow into the sea or other bodies of water. The silt may settle on the river beds raising the river bed and causing flooding of the river banks which can destroy the habitats of animals living near the river. The silt also makes the river very cloudy and prevents adequate light from getting to the plants which need the light to make food. The cloudiness may also affect the hatching of fish eggs and if the water flows into the sea the coral reefs may become so affected that they die.

4. List the pollutants that can find their way into water.

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5. How can rainwater indirectly cause harm to a coral reef many miles away from the place it falls?

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6. Carry out research to find out how the following affects our environment: (a) oil spills (b) waste from cruise ships (c) pesticides. Use the information collected to create a poster, booklet, poem or other method to share with others in your class.

ATOMS, ELEMENTS, COMPOUNDS AND MIXTURES

An atom is the smallest unit of matter. Atoms are made up of protons and neutrons found in the nucleus and electrons circling in shells on the outside of the nucleus. 1. Draw a diagram of an atom below.

An element contains one type of particle (atom).2. The fill in the blanks story from the syllabus to be given to students for them to stick in their books.

Once upon a time, as I floated away light as (He) _________, I saw something as valuable as (Au) __________

but it was even rarer like (Pt) _________. I picked it up and found it was as heavy as (Pb) ________. It reacted

easily with water like (K) _________ and (Na) _________ and brightened the place like (Ne) __________ in

bulbs. I looked around and saw a piece of (Zn) ________ from a roof, half-buried in the (Si) __________ of the

sand. As I used the (Fe) _______ spade to unearth the piece, I started gasping due to lack of (O) _________ ,

and realised that a gas cloud of (Cl) _______had been accidentally released from the nearby water treatment

plant. I moved as quickly as (Hg) _________ in a thermometer, to put as much distance between myself and

the cloud as I could, then stopped to have some (Mg) ______ salts to settle my upset stomach. An old woman

standing close by shouted that I was lucky to be alive and should guard my health as if it was valuable like (Ag)

_______ is regarded. I thanked her and climbed out of the valley on cables of (Cu) _________ to see labourers

applying ‘whitewash’ containing (Ca) ________ to the fences and around the trunks of the trees, as Christmas

would soon be here. Unfortunately, I fell and bruised my knee and so had to put (I) _________ on the wound

to prevent infection. Nearby, a huge industrial complex was releasing toxic clouds containing (S) __________

dioxide and my eyes began to blur and my throat constrict, and I began falling as the vehicles whizzing by

released the (C) __________ dioxide in their exhaust, I woke up out of the dream I was having. I then brushed

my teeth with the toothpaste containing (F) _________ and went to my bed as it was late at night.

A compound contains two or more elements (atoms) that are chemically combined and not easy to separate. e.g. carbon dioxide, ammonia, water. Compounds have different properties from the elements they are made from: hydrogen is an explosive gas, oxygen is used to burn things but together they make water which can extinguish fires.

A mixture contains two or more elements (or two or more different substances or compounds) that are physically combined and can be easily separated (e.g. paint, cleaning products, sugar water, most drinks etc.).

TABLE SHOWING A COMPARISON OF ELEMENTS COMPOUNDS AND MIXTURES.

A solution is a mixture of a dissolved substance (or substances) in a solvent (liquid) (e.g. sugar in water, carbon dioxide in soft drinks, lemon juice in water for lemonade).

A suspension is a mixture of fine particles of an insoluble solid spread throughout a liquid. (e.g. chalk in water, mud in water, sand in water.

Various separation techniques may be used to separate mixtures. The separation method used is dependent on the particle size, difference in density, components in the substance, whether the solute is dissolved in the liquid and other physical properties. For example:

Method Used to separate Apparatus used ExamplesFiltering (Filtration) an insoluble solid

from a liquid• Tea leaves from a

cup of tea• Sand from a

mixture of sand and water

Decanting immiscible liquids e.g. oil and water

Oil and water

Evaporation dissolved substances from a solution

• Salt from seawater

Simple distillation (Evaporation followed by condensation)

and collect the liquid from the dissolved solid in a solution or one liquid from a mixture of liquids

• Water from seawater

• Water and ink

Fractional Distillation liquids with similar boiling points

Alcohol and water.

Chromatography coloured dissolved substances from solution

• The colours found in ink

• The food colourings found in fruit juice

TABLE SHOWING SEPARATION TECHNIQUES

METALS AND NON-METALS

Metals are: dense, hard, good conductors of heat and electricity, ductile (can be drawn into wires), malleable (can be hammered into sheets). Sonorous (make a sound), have lustre (shiny) and have high melting and boiling points.Non-metals are: poor conductors of heat and electricity, dull (in appearance) light, soft, brittle and have low densities.

3. Fill in the blanks by choosing the correct word or phrase from the brackets.

a. Carbon, oxygen, iron and gold are all __________________ (metals/elements/compounds).

b. Things which contain only one type of atom are called __________________ (elements/compounds).

c. Compounds always contain __________________ (one/more than one) type of atom.

d. Water has the formula H2O. There are two elements in water. Hydrogen is one, and __________________

(carbon/oxygen/nitrogen) is the other. Water is __________________ (an element/a compound). The

formula tells us that water contains __________________ (more/less) hydrogen than oxygen.

4. Match the name of the element to the correct description. One has been done for you as an example.

Description Element

This is a solid that can be used to make heavy masses. Some saucepans or frying pans are made from this.

copper

This is a brown, shiny solid used for making coins or ornaments. Brass bells contain this element.

helium

This is a yellow solid which can be found as crystals or powder. It melts easily.

iron

This is a gas that is used to fill balloons. gold

This is a shiny silvery solid. It can be made into thin sheets of foil which can be used to wrap food up.

sulphur

This is a shiny yellow solid that is used to make rings and necklaces. It is a very good conductor of electricity.

aluminium

CCSLC PLANNING AND DESIGN SBA – MODULE 2 (To be complete on a separate sheet of paper.)

NAME:

PROBLEM: A student found an unlabelled bottle of a transparent liquid in the kitchen. The student believes that it is water. Design an experiment to determine if the substance is pure water.

HYPOTHESIS: If the liquid is pure water then ... OR The liquid is pure water because pure water always …

AIM: To determine if … (This must be based on the hypothesis.)

APPARATUS AND MATERIALS: List all equipment and substances needed.

METHOD: To be written as step by step (numbered) instructions. Use an appropriate method of separation. Repeat experiment to ensure reliable results.

CONTROLLED VARIABLES: Things kept constant during the experiment to ensure that a fair test is done.

EXPECTED RESULTS: What is expected to happen if the hypothesis is true?

LIMITATIONS: Factors which could not be controlled that could result in inaccurate results.

ACIDS AND BASES Acids are substances which produce free hydrogen ions in aqueous solutions. Examples of acids: vinegar, Ascorbic Acid, sting of ants (Formic Acid), Hydrochloric Acid (HCl), Sulphuric Acid (H2SO4).

Acids: have a pH less than 7; a sour taste but most acids are dangerous to ingest; are corrosive (they can burn flesh); turn litmus paper from blue to red; conduct electricity; react with certain metals to give a salt and hydrogen gas; react with carbonates to form salt, water and carbon dioxide gas; react with bases to form a salt and water only. This reaction is known as a neutralization reaction since the effect of the acid is cancelled out by the base. The neutral substance (salt ) produced has a pH value of 7.

Bases are oxides or hydroxides of metals that react with acids to form salt and water. Examples of bases: for example Sodium Hydroxide (NaOH), Magnesium Hydroxide (Mg(OH)2), Ammonium Hydroxide/Ammonia solution (NH4OH). Bases: have a pH greater than 7; neutralize acids and some are insoluble in water. Alkalis are soluble bases. Bases / alkalis: have a bitter taste; are corrosive; are soapy to touch; turn red litmus blue; conduct electricity; often react with salt solutions to form insoluble precipitates.

INDICATORS

An indicator is a substance which varies in colour depending on whether it is in alkaline, acidic or neutral conditions. Indicators may be liquid solutions or a paper.

Colour Changes of some Common IndicatorsIndicator Litmus Methyl Orange Screened Methyl

OrangePhenolphthalein

Colour with acid red Red Light red colourlessColour with base blue Yellow green pink

Litmus is the most common indicator. While the indicators above show whether something is acidic or alkaline, they do not show how acidic or alkaline a solution is. Universal Indicator is a mixture of indicators. It has different colours in solutions of different pH. It can be used to determine the strength or weakness of an acid or alkaline substance.

1. Collect at test the pH of six common household substances in order to classify them as acidic, alkaline or neutral.

Place two drops of each substance to be tested in the test tubes provided. Add two drops of universal indicator to the substances in the test tubes. Match the final colour of the universal indicator with the colours on the pH scale provided. Record your observations below and classify each substance as (i) strong acid (ii) weak acid (iii) neutral (iv) weak alkali (v) strong alkali.

Classification of Common Household SubstancesSubstance tested Colour Change of

Universal IndicatorpH Value Classification of

Substance

2. What element is present in all acids? _________________

3. What is a base? __________________________________________________________________________

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4. What is a soluble base called? ___________________

5. What are formed when an acid is neutralized by a base? __________________________________________

6. What is an indicator? ______________________________________________________________________

7. What kind of solution has a pH of 4 or 5? ___________

8. The following table shows the pH of a number of aqueous solutions.

Solution A B C D E

pH

a) (i) Which solution is most acidic? __________ (ii) Which solution is most alkaline? ___________

(iii) Which solution is neutral? ___________ (iv) Which solution could be salt water? ___________

(v) Which solution could be vinegar?

b) Circle the combinations below which could give a neutral solution on mixing.

(i) A + B (ii) C + D (iii) B + D (iv) C + E (v) A + B + C + D + E

9. Discuss the role of neutralisation in (a) the treatment of heartburn/indigestion (b) insect bites - wasps and

bees (d) the treatment of acidic soils.

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NAME: …………………………………………………………………………….. FORM: …………………..TITLE: ACIDS, BASES AND NEUTRAL SUBSTANCESAIM: To classify three unknown substances as acidic, basic or neutral.APPARATUS:Test tubesTest tube rackDroppersSpotting tile

MATERIALS:Solution ASolution BSolution CUniversal indicator solution with pH chartRed and Blue Litmus paper

METHOD: 1. Place one piece of red litmus paper in one well of the spotting tile. Add two drops of solution A. Record

observation.2. Place one piece of blue litmus paper in one well of the spotting tile. Add two drops of solution A.

Record observation.3. Place two drops of universal indicator into a test tube. Add two drops of solution A. Record

observation. Compare final colour to the colours on the pH chart provided and record the pH value.4. Repeat steps 1-3 using solution B.5. Repeat steps 1-3 using solution C.

OBSERVATIONS:Table showing colour changes of indicators and pH value of solutions.Solution Colour Change of pH Value

Red Litmus Paper Blue Litmus Paper Universal Indicator SolutionA

B

C

DISCUSSION: Classify solutions A, B and C as either strongly acidic, weakly acidic, strongly basic, weakly basic or neutral. Give reasons for your answer.__________________________________________________________________________________________

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Suppose lime juice was tested in the same way. What would you expect to observe?

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CONCLUSION: Classify solutions A, B and C as acidic, basic or neutral.

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