Manipulative
skills in chemistry internal assessment
Manipulative
skills are assessed summatively. This means that one overall mark will be
given. The skills
assessed
should cover most of the two-year course, and the mark given should reflect the
student’s general
ability
near the end of the course. This mark is not an average nor does it relate to a
given investigation. It is
important
therefore that the scheme of work sets the students a variety of tasks and that
they carry out a
range
of different techniques. The examples below are suggestions to aid assessment
of manipulative skills
and
are not considered to be a prescribed list.
Note:
No supporting evidence is required for moderation of manipulative skills.
Aspect
1: Following instructions
The
student:
reads/listens
to instructions before asking for help
only
starts the investigation after having read/listened to all the instructions
is
able to follow a sequence of several written or verbal instructions with little
assistance.
Aspect
2: Carrying out techniques
Measuring
volume
The
student:
uses
a suitable cylinder/pipette/burette size
does
not overfill cylinder/pipette/burette
places
his/her eyes at the height of the meniscus.
Measuring
mass
The
student:
handles
the balance appropriately when transporting it
adjusts
the balance to zero before starting
uses
a suitable container for the substance to be measured.
Measuring
temperature
The
student:
leaves
his/her thermometer in a safe place when it is not in use
refrains
from touching the sides of the container with the thermometer when
measuring
the temperature of a liquid
leaves
the thermometer in the liquid when measuring the temperature of that liquid.
(Vacuum)
filtering
The
student:
folds/places
the filter paper correctly
uses
equipment/filter paper of adequate size
adds
a reasonable amount of liquid to the funnel.
Making
solutions
The
student:
uses
a funnel to add the solid to the volumetric flask
washes
the container containing the solid several times and adds the water to the
volumetric
flask
carefully
adds water to the mark.
Titration
The
student:
makes
one trial before taking measurements
takes
at least three measurements
takes
care towards the end of the titration.
Assembling
equipment
The
student:
ensures
that different parts are clamped safely together without forcing the glass
uses
anti-bumping granules for boiling liquid
chooses
the correct size/shape of flasks
places
the thermometer at an adequate height
connects
the cooling water adequately.
Collection
of gas
The
student:
takes
care that the assembly is airtight
takes
care that the equipment does not contain air before starting.
Setting
up electrical circuits
The
student:
connects
up a circuit without help
connects
the ammeter in series and the voltmeter in parallel
connects
the positive side of the ammeter/voltmeter to the positive side of the power
supply
uses
a suitable scale.
Aspect
3: Working safely
The
student:
always
wears safety clothing appropriate to the task, such as eye protection, lab
coats
and gloves
pays
proper attention to written or verbal safety instructions and hazard symbols
lights
and uses the Bunsen burner safely
places
flammable substances far away from flames
takes
care, when heating, that the test tube does not point at other students
takes
care that the test-tube holders are not in the flame
ensures
that solutions are not heated to complete dryness
places
hot equipment on heat mats
uses
the fume cupboard for all poisonous volatile liquids
washes
his/her hands after using toxic substances in the laboratory
takes
care not to mix spatulas for different chemicals, or caps off different bottles
leaves
glassware on solid surfaces and ensures that glassware cannot be knocked or
roll
off the surface
reports
when equipment has been broken
avoids
wasting chemicals
cleans
spilled chemicals or broken glassware immediately
washes
and tidies up the equipment after use
disposes
of chemicals in a suitable manner
shows awareness of the impact of chemicals on the environment.