MAKING SENSE OF THE MATERIAL WORLD: LEVEL 5

ACHIEVEMENT OBJECTIVES

Students can

(a) investigate familiar substances and describe, using the concept of the particle nature of matter, how they may exist as solids, liquids, and gases, e.g., water, candle wax;
(b) distinguish between elements, compounds, and mixtures, using simple chemical and physical properties, and describe a simple model of the atom;
apply their knowledge of chemical and physical properties of substances to investigate their safe and appropriate use in the home and the community, e.g., swimming pool chemicals, oven cleaners, fuels;
investigate some important types of substances and the way they change chemically in everyday situations, e.g., metals, acids, bases, fuels;
research and describe how selected materials are manufactured and used in everyday goods and technology, e.g., plastics from fossil fuels, glass from sand, paper from wood.

Note: Students should be starting to use the 'language' of chemists, that is, symbols of elements and formulae of simple molecules and compounds.

Students could be learning by:

photographing local telephone or power lines in winter and summer and observing differences;
researching actions of solvents and establishing their potential danger when abused by people;
making and tasting sherbert mixtures to gain an understanding of the reaction of acids and bases;
working co-operatively in groups to make casein glue, and comparing it with commercial adhesives;
investigating the use of mordants in dyeing fabrics;
finding out about the use of sacrificial metals in the boating industry;
extracting a natural indicator from red cabbage and using it to test the pH of a range of household acids and bases;
making hokey pokey and identifying what is happening chemically when the baking soda is added;
investigating the chemicals produced when a candle burns;
examining the effect of acids and bases on a wide variety of common substances, such as plastics, glass, concrete, marble, gravel, 'tin' cans, nails;
finding out about the paper-making process at a paper mill in New Zealand;
preparing a classroom poster showing the chain of 'events' in the process 'from Sun to plastic food-wrap';
comparing (by properties, appearance, and cost) the use of plastic and glass to make kitchen utensils;
gathering information on the processes of glass manufacture through literature searches and by visiting glass production industries.

ASSESSMENT EXAMPLES

Teachers and students could assess the students':

ability to communicate ideas, when they explain their diagrams which represent the arrangement of particles in a candle, in molten wax, and in wax vapour;
classification of substances as compounds or mixtures, when the students draw particle diagrams;
understanding of the division of elements into two broad groups, when the students shade in a blank of the periodic table indicating the positions of the metals and non-metals;
understanding of the care needed in storing substances around the home, when the students produce a poster illustrating this;
understanding of the difference between chemical and physical change, when the students group, from a list of situations, those that involve physical and/or chemical changes;
knowledge of the process of neutralisation, when the students are able to prepare common salt from dilute solutions of hydrochloric acid and caustic soda;
ability to communicate their ideas clearly, when the students give a talk on the impact of a technological advance, e.g., bicycle frames, surfboards, tennis racquets;
information-gathering skills, when the students carry out an information search on the production of plastics from fossil fuels.