Y CYD-BWYLLGOR ADDYSG CYMREIG
CERTIFICATE OF EDUCATION
GENERAL SCIENCE 0b
questions, TWO from each section.
Special importance is attached to large, clearly labelled
Diagrams, provided they make the answer easier to
Understand. Time should note be spent in making
State the Principle of Archimedes, and describe
carefully an experiment you have carried out to verify
Explain briefly (a) why a hydrogen
but will eventually stop rising; (b) how a balloonist can
control the altitude of his balloon.
briefly between conduction, convec-
tion, and radiation of heat.
Describe carefully an experiment by which
could determine which of two metals, e.g. copper and
iron, is the better conductor of heat.
Explain the principle of the Davey
3. What is the
essential difference between a luminous
body and a non-luminous body ? State, giving one
reason in each case, into which of these classes you
would place each of the following: a book; Mars; the
Sun; a glass prism; a red-hot cinder.
By means of a labelled diagram
only, show how
total and partial eclipses of the moon are caused.
Why do we always see the same side of the moon?
State two differences and two similarities between
sound waves and light waves.
Describe experiments you would carry out
demonstrate the factors which determine the pitch of a
note given out by a string.
Briefly explain what is meant by the
the frequency of middle C is 256.
5. Make a labelled
drawing of a simple voltaic cell,
And show the direction in which the current flows in a
wire which is connected to the terminals of the cell.
Describe how you would use such a cell to
Explain clearly the action of a fuse in
6. State two
reasons why river water may be unfit
Draw the apparatus you would use to
water from a sample of river water.
Comment on the suitability of the pure
obtained for each of the following purposes: (a) for
drinking; (b) for electrolysis; (c) for keeping goldfish in.
7. Make a labelled
drawing of the apparatus you
would use to prepare several gas jars of carbon dioxide.
Name one substance which will burn in
dioxide, name the resultant products, and describe their
Briefly explain why the carbon dioxide
the atmosphere remains approximately constant.
carefully an experiment by which you
could show that there is a change in weight when a
substance, e.g. magnesium, is burned in air.
Describe another experiment by which you
could find what fraction of air by volume is used in
In what ways does combustion resemble
Describe briefly how temporary hardness in water
may be caused naturally.
Explain the changes which occur when soap
with such water.
Describe an experiment you would carry
find which of two samples of water was the harder.
10. Make a labelled
drawing of the apparatus you
would use to prepare hydrochloric acid in aqueous
solution, and explain carefully the precautions you
State two commercial uses of this acid,
purposes which it serves in the human body.
Give two tests by which you could
between dilute hydrochloric acid and brine.
11. Explain briefly what
is meant by 'photo-
Describe experiments, one in each
case, to show
that (a) oxygen is evolved during photosynthesis,
(b) light is necessary for photosynthesis.
12. Make a labelled
diagram of a vertical section
through the flower of a buttercup.
Describe fully how this
flower is pollinated, and
make a labelled drawing of the fruit which is formed.
13. What is meant by the
circulation of nitrogen in
nature, and how is it brought about.
In what type of foodstuff does man
into the body? State what use is made of the nitrogen
which is assimilated, and state what happens to the
Make a labelled diagram showing the reproduce-
tive organs of a female mammal containing an embryo.
Briefly describe the structure of
the placenta, and
state its functions.
Name the structures responsible for
of the embryo plant, (b) nourishment of the embryo
15. Describe the
habits of the housefly, and hence
explain why it is regarded as a dangerous spreader of
State why the elimination of each
of the following
is desirable: (a) the roundworm; (b) the flea.