Chapter 1 - Science and Technology

TEACHERS’ GUIDE

CHAPTER 1 - SCIENCE AND TECHNOLOGY

CONCEPT MAP

SCIENCE

uses

SCIENTIFIC SCIENTIFIC

METHOD generates KNOWLEDGE

is important

branches

OBSERVATION BIOLOGY CHEMISTRY PHYSICS

OTHER KNOWLEDGE,

summed up EXPERIENCE, SKILLS

applied in

CLASSIFICATION

GENERALISATION

TECHNOLOGY

explained by

makes

THEORY/MODEL

MATERIALS, TOOLS

MACHINES, CONSTRUCTIONS

tested by

EXPERIMENTS

1.1 INTRODUCING SCIENCE AND TECHNOLOGY

Aims:

To interest students in science and technology and the changes they have caused.
To raise the questions "What are science and technology?" and to start answering them.

Activities:

Discuss with students, some differences between traditional and modern life. Use the pictures to start with if necessary, but extend the discussion to the students' own experiences.

Answers:

Q1.Science is (i) a method for finding out about the world, and (ii) the detailed knowledge which scientists have discovered about the world.
Q2. Science is about discovering things, technology is about making, using and doing things.
Q3/4. Relevant differences include housing materials, domestic appliances, water supply, electricity, gas, clothing materials, telephone, radio, TV, computer, means of transport, health practices and techniques (clinics, immunisations, medicines, X-rays, surgery) etc.

1.2 WHAT IS SCIENCE?

Aims:

To extend students' idea of science to include the three main branches of knowledge and the main steps in the scientific method.

Activities:

Reading and discussion. Students should learn the three main branches, what each one studies, and the four main steps in the scientific method.

Answers:

Q1. Biology could study humans, flowers, food, snakes. Chemistry could study air, food, rocks, stars, gold. Physics could study energy, reflections, stars, thunder. Other sciences could include Astronomy for the study of stars and Geology for the study of rocks. Science does not usually study religion, beauty, stories and war. These are human activities or ideas, not things we observe in the natural world.
Q2. Scientists get new ideas by thinking about what they have observed. They also use the knowledge they already have, and a bit of imagination too. They find out if their ideas are correct by doing experiments to check them.
Q3. Observing means examining closely and carefully. Summarising means trying to describe the main things we have observed in a short but accurate way.

1.3 OBSERVING

Aims:

To help students understand what observation means.
To introduce the idea of using instruments to improve observation.
To introduce students to the names and purposes of three common optical instruments.
To show students how to use a hand lens.
To introduce the idea that scientists always keep records of observations.

Activities:

Practical activities to practise observation and recording. Include using a hand lens. Include at least one safe activity which uses smell and one which uses touch. (NB You should forbid tasting in science lessons). If microscopes are available, set up several on low power and focus on simple objects such as a torn edge of paper, a hair, a fly's wing etc for students to observe. (NB Do not try to teach them to adjust the microscope yet).

Answers:

Q1. Observation means examining something closely. We can use all our senses. The sense we use most is sight.
Q2. Length is measured with a ruler or tape measure. Encourage students to think about measuring volume, time and temperature first. Then let them look at sections 1.5 and 1.6 to check their answers.
Q3. (i) hand lens (or very low power microscope), (ii) telescope, (iii) microscope.
Q4. They record (i) so they will not forget and (ii) so others can check the observations. If the observations are not accurate they will not help us to understand the world around us.

1.4 MEASURING LENGTH AND AREA

Aims:

To introduce SI units in general, and units of length and area in particular.
To give practice in measuring length and converting between mm, cm and m.
To revise the idea of area as surface covered, and formulae for calculating it.
To introduce the idea of estimating the area of irregular shapes using graph paper, and to give practice in doing this.

Activities:

Practical exercises measuring lengths using both rulers and tape measures. Hints and suggestions are included in the book (answers below), but these should be extended if possible.
Go through the method given for estimating the area of irregular shapes and encourage students to check for themselves the example given in the book. Emphasise that this is an approximate method.
Add more practical exercises on area, especially for irregular shapes. (Eg students could draw round their own feet on graph paper and count to estimate their areas).

Answers:

Q1. Left - right (i) 82 (or 83) mm, (ii) 8.2 (or 8.3) cm

Top - bottom(i) 90 mm (ii) 9.0 cm

Q2. See the diagram in the book. Trap the coin on the ruler between two set-squares.
Q3. The most accurate way is to wrap a strip of paper round the edge so that it overlaps, then pierce through the overlap with a pin. Unwrap the paper and measure the distance between the pin holes!
Q4. Measure the thickness of 50 pages with a ruler (about 5 mm), then divide by 50 (answer about 0.1 mm).
The area of the "area" rectangle is 82 x 45 = 3690 mm2, or 8.2 x 4.5 = 36.9 cm2.

1.5 MEASURING VOLUME AND TIME

Aims:

To introduce units of volume and time.
To revise the idea of volume as space occupied, and formulae for calculating it.
To introduce the measuring cylinder and teach students how to use it.
To give practice in measuring volume (including volume by displacement for an irregular object) and converting between ml, cm3 and l.
To introduce the stop watch/clock and give practice in using it.

Activities:

Examine the labels of popular drinks to check the volumes marked on them.
Practical exercises measuring volumes of liquids with measuring cylinders. (For accurate readings, make sure students have the cylinder upright and read the bottom of the meniscus at eye level).
Practical exercises measuring volume by displacement.
Practical exercises using a stop watch/clock (or wrist watch) for timing different events.

Answers: (Measuring the volume of irregular solids by displacement)

Q1. The volume of the stone in the diagram is 20 cm3.
Q2. (i) To find the volume of something small like a paper clip, first find the volume of 50 or 100 by displacement, then divide by the number used. (ii) For something too big to go into the cylinder, we must measure the volume of water which overflows when it is displaced from a full container. You may have a special overflow can (Eureka can) for this. (iii) The volume of an irregular object that floats, can be found by displacement if it is pushed very carefully under the water (eg with the points of a pair of dividers).

(Time)

Q3. The stop watch and the stop clock both show 1 min 15 s.

1.6 MEASURING MASS AND TEMPERATURE

Aims:

To introduce units of mass and temperature.
To introduce mass as a word to replace weight at this stage in the course. (It would be inappropriate to explain why at this point!).
To introduce the balance for measuring mass and give practice in using it.
To introduce laboratory and clinical thermometers and give practice in using them.

Activities:

Practical exercises measuring mass with different kinds of balances (as available).
Practical exercises measuring temperature using clinical and laboratory thermometers. (NB Warn students about the fragility of thermometers and supervise them closely. Use clinical thermometers only to check the temperature of body parts; always "shake down" after each reading. Use the laboratory thermometer to measure temperatures up to the boiling point of water only. Never try to "shake down"!)

Answers:

Q1. (i) With a beam balance, the object is placed on one scale pan, then standard masses are added to the other pan to balance it exactly. (ii) With a top pan balance, the object is simply placed on the pan and the mass is read from the scale.
Q2. Measure the volume and mass of 100 pins; then divide each by 100 to find the volume and mass of one pin.
Q3. (i) 37 oC (ii) 100 oC(iii) variable - about 35oC in most tropical countries but higher in some very dry regions (iv) clinical thermometer 37.4 oC; laboratory thermometer 26 oC.

1.7 SUMMARISING AND EXPLAINING WHY

Aims:

To introduce students to the idea that scientists sum up their observations by classification and generalisation, and to help them understand these two terms.
To introduce a scientific law as a tested generalisation about reliable observations.
To introduce a theory as an idea scientists use to explain why things happen.

Activities:

Reading and discussion.

1.8 DOING EXPERIMENTS

Aims:

To summarise the steps in the scientific method.
To emphasise that experiments are mostly used for checking laws and theories.
To introduce the idea of using laws and theories to predict what will happen in an experiment.
To introduce students to some simple laboratory equipment and its representation in diagrams.

Activities:

Reading and discussion.
One or two simple practical exercises (or demonstrations) in which students use their knowledge to try to predict what will happen, and then check their predictions.
Looking at and handling items of simple laboratory equipment such as those illustrated.

Answers:

Q1. Classification means putting similar things together into named groups or sets. Generalisation means summarising a set of observations in a short general statement.
Q2. A generalisation becomes a law after it has been checked many times by experiment and has been accepted by most scientists.
Q3. Scientists usually do experiments to check laws or theories.
Q4. Pictures look like the real thing. Diagrams are simplified pictures; each item is represented by an outline only (the outline is usually a section through the item). Diagrams usually have labels to name each of the main items.

1.9 SCIENCE AND SCIENTISTS

Aims:

To interest students in scientists and their work, and provide a few historical examples.
To help students realise that scientific knowledge has accumulated over several hundred years through the activities of scientists.

Activities:

Reading and discussion. Students could be asked to find out about other famous scientists and their work from library books or the internet. They could report to the class about their favourite scientists.

1.10 TECHNOLOGY IN ACTION

Aims:

To interest students in technology and the way it affects peoples’ lives.
To clarify what technology is, and how it differs from science.
To provide students with examples of technology.

Activities:

Reading and discussion. Looking at and handling any examples of technology that may be available. Students could be asked to add to the examples given from their own experiences or research.

Answers:

Q1. The main uses of iron (steel) in building are (i) corrugated iron for roofs or walls, and (ii) iron rods to strengthen (reinforce) concrete.
Q2. (i) Synthetic fibres are fibres (threads) of substances such as nylon, polyester or rayon which do not occur in nature but have been manufactured. The word synthetic means made by people. (ii) Textiles are cloths woven from any kind of fibre, natural or synthetic.
Q3. (i) Sewing machine.(ii) Generator (of limited size), or Power Station (huge!).

1.11 SCIENCE, TECHNOLOGY AND CHANGE

Aims:

To get students to think about, and evaluate, the changes caused by science and technology.
To make students aware that science and scientists have certain limitations.
To introduce the idea of scientific research and distinguish between pure and applied science.
To make students aware of the important role of publication and peer review in scientific research.
To give students some awareness of the different cultures of science and technology.

Activities:

Reading and discussion. The interaction of science and technology with local culture could be a good topic for essays or a debate or a wall display. If you do this, discourage students from making assertions which they can not support with evidence (either from their own experience, from the experience of people they know, or from reliable internet sources and books).