Teachers Overview

Please see below teachers overview for each Chemistry video.

Video clip code	Experiment title (from WJEC's lab book)	Specification reference	Additional notes
01	Gravimetric analysis	AS Unit 1.6 The Periodic Table
02	Identification of unknown solutions by qualitative analysis	AS Unit 1.6 The Periodic Table
03	Preparation of a soluble salt by titration	AS Unit 1.7 Simple equilibria and acid-base reactions	Contains a more detailed description of titrimetric technique.
04	Standardisation of an acid solution	AS Unit 1.7 Simple equilibria and acid-base reactions	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
05	Back titration	AS Unit 1.7 Simple equilibria and acid-base reactions	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
06	Double titration	AS Unit 1.7 Simple equilibria and acid-base reactions	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
07	Indirect determination of an enthalpy change of reaction	AS Unit 2.1 Thermochemistry	Please emphasis keeping heat loss to a minimum when mixing reagents.
08	Determination of an enthalpy change of combustion	AS Unit 2.1 Thermochemistry
09	Investigation of a rate of reaction by a gas collection method	AS Unit 2.2 Rates of reaction
10	Study of an ‘iodine clock’ reaction	AS Unit 2.2 Rates of reaction
11	Nucleophilic substitution reaction	AS Unit 2.6 Halogenoalkanes
12	Preparation of an ester and separation by distillation	AS Unit 2.7 Alcohols and carboxylic acids
13	Construction of electrochemical cells and measurement of Ecell	A2 Unit 3.1 Redox and standard electrode potential	Ensure clean metal electrodes (e.g. clean with emery paper).
14	Simple redox titration	A2 Unit 3.2 Redox reactions	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
15	Estimation of copper in copper(II) salts	A2 Unit 3.2 Redox reactions	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
16	Determination of the order of a reaction	A2 Unit 3.5 Chemical kinetics
17	Determination of an equilibrium constant	A2 Unit 3.8 Equilibrium constants
18	Titration using a pH probe	A2 Unit 3.9 Acid-base equilibria	Refer students to ‘Preparation of a soluble salt by titration’ (C03) for detailed description of titrimetric technique.
19	Synthesis of a liquid organic product	A2 Unit 4.8 Organic synthesis and analysis
20	Synthesis of a solid organic product	A2 Unit 4.8 Organic synthesis and analysis
21	Two-step synthesis	A2 Unit 4.8 Organic synthesis and analysis	Could be performed over a number of sessions.
22	Planning a sequence of tests to identify organic compounds	A2 Unit 4.4 Aldehydes and ketones	Vary the combinations of compounds throughout the student group.
23	Paper chromatography	A2 Unit 4.8 Organic synthesis and analysis

Please click here for the answers to the Chemistry questions.

Please see below teachers overview for each Biology video.

Video clip code	Experiment title (from WJEC’s lab book)	Specification reference	Additional notes
01	Food tests	AS Unit 1.1 Chemical elements are joined together to form biological compounds	When the procedures for testing the different food types have been mastered, mixtures of food types can be used to confirm understanding.
02	Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing	AS Unit 1.2 Cell structure and organisation
03	Preparation and scientific drawing of a slide of onion cells including calibration of actual size and magnification of drawing	AS Unit 1.2 Cell structure and organisation	This practical uses the calibration of the microscope carried out in ‘Preparation and scientific drawing of a slide of onion cells including calibration of actual size and magnification of drawing’ (B02).
04	Determination of water potential by measuring changes in mass or length	AS Unit 1.3 Cell membranes and transport	Measuring percentage mass change gives a more precise estimate of the point of incipient plasmolysis. Discussion of the relationship between solute potential and water potential before the practical may assist students in their understanding of what is causing the change in tissue mass or length.
05	Determination of the solute potential by measuring the degree of incipient plasmolysis	AS Unit 1.3 Cell membranes and transport	This practical has a similar aim to ‘Determination of water potential by measuring changes in mass or length’ (B04) (finding the point of incipient plasmolysis) but uses a different approach.
06	Investigation into the permeability of cell membranes using beetroot	AS Unit 1.3 Cell membranes and transport	If a colorimeter is not available candidates could evaluate the validity of obtaining their results using subjective judgement.
07	Investigation into the effect of temperature or pH on enzyme activity	AS Unit 1.4 Biological reactions are regulated by enzymes	Standing the tubes against a white card may assist in judging the endpoint.
08	Investigation into the effect of enzyme or substrate concentration on enzyme activity	AS Unit 1.4 Biological reactions are regulated by enzymes	The discs can stick together when cut from multiple pieces of filter paper – separate beforehand. If the discs start to rise before reaching the bottom, adjust the concentration of hydrogen peroxide used.
09	Simple extraction of DNA from living material	AS Unit 1.5 Simple extraction of DNA from living material
10	Scientific drawing of cells from slides of root tip to show stages of mitosis	AS Unit 1.6 Genetic material is copied and passed on to daughter cells	Care must be taken not to overheat the slide as it may crack.
11	Scientific drawing of cells from prepared slides of developing anthers to show stages of meiosis	AS Unit 1.6 Genetic material is copied and passed on to daughter cells	This practical uses the calibration of the microscope carried out in ‘Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing‘ (B02).
12	Investigation into biodiversity in a habitat	AS Unit 2.1 All organisms are related through their evolutionary history
13	Investigation into stomatal numbers in leaves	AS Unit 2.2 Adaptations for gas exchange	This practical uses the calibration of the microscope carried out in ‘Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing‘ (B02).
14	Dissection of fish head to show the gas exchange system	AS Unit 2.2 Adaptations for gas exchange	Salmon heads are ideal if available, or mackerel if not.
15	Scientific drawing of low power plan of a prepared slide of T.S. leaf, including calculation of actual size and magnification of drawing	AS Unit 2.2 Adaptations for gas exchange	This practical uses the calibration of the microscope carried out in ‘Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing‘ (B02).
16	Investigation into transpiration using a simple potometer	AS Unit 2.3 Adaptations for transport
17	Scientific drawing of low power plan of a prepared slide of T.S. artery and vein, including calculation of actual size and magnification of drawing	AS Unit 2.3 Adaptations for transport	This practical uses the calibration of the microscope carried out in ‘Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing‘ (B02).
18	Dissection of a mammalian heart	AS Unit 2.3 Adaptations for transport	Lamb or pig’s hearts are available in supermarkets but are sliced across the atria. Local butchers may provide hearts with blood vessels still attached.
19	Investigation of dehydrogenase activity in yeast	A2 Unit 3.1 Importance of ATP	Yeast can often have an unexpectedly high optimum temperature. It can also sometimes go into temperature shock when first prepared, so should be activated beforehand.
20	Investigation into the separation of chloroplast pigments by chromatography	A2 Unit 3.2 Photosynthesis uses light energy to synthesise organic molecules	Spinach or nettle leaves work well. All the pigments may not be visible, especially if the suspension is not concentrated enough.
21	Investigation into the effect of light on the rate of photosynthesis	A2 Unit 3.2 Photosynthesis uses light energy to synthesise organic molecules	The production of the algal balls can also be carried out by pouring the suspension into a narrow bore syringe without the plunger and letting it drip through into calcium chloride.
22	Investigation into the role of nitrogen and magnesium in plant growth	A2 Unit 3.2 Photosynthesis uses light energy to synthesise organic molecules
23	Investigation into factors affecting respiration in yeast	A2 Unit 3.3 Respiration releases chemical energy in biological processes	Yeast can often have an unexpectedly high optimum temperature. It can also sometimes go into temperature shock when first prepared, so should be activated beforehand.
24	Investigation into the numbers of bacteria in milk	A2 Unit 3.4 Microbiology	Ensure aseptic techniques are carried out as detailed by CLEAPSS.
25	Investigation into the abundance and distribution of plants in a habitat	A2 Unit 3.5 Population size and ecosystems
26	Dissection of a mammalian kidney	A2 Unit 3.7 Homeostasis and the kidney	Lamb or pig’s kidneys are available in supermarkets but are cut open and usually have no blood vessels or ureters attached. Local butchers may provide kidneys with these still attached.
27	Investigation of the digestion of starch agar using germinating seeds	A2 Unit 4.2 Sexual reproduction in plants	Employ aseptic technique to minimise fungal contamination.
28	Dissection of wind and insect-pollinated flowers	A2 Unit 4.2 Sexual reproduction in plants
29	Scientific drawing of cells from prepared slides of anther	A2 Unit 4.2 Sexual reproduction in plants	This practical uses the calibration of the microscope carried out in ‘Calibration of the light microscope at low and high power, including calculation of actual size of a structure and the magnification of a structure in a drawing‘ (B02).
30	Experiment to illustrate gene segregation	A2 Unit 4.3 Inheritance
31	Investigation of continuous variation in a species	A2 Unit 4.4 Variation and evolution

Please click here for the answers to the Biology questions.

Please see below teachers overview for each Physics video.

Video clip code	Experiment title (from WJEC’s lab book)	Specification reference	Additional notes
00	Using a Vernier	General skills	This video clip shows how to use a Vernier / digital caliper as required in other experiments in this series, as highlighted below.
01	Measurement of the density of solids	AS Unit 1.1 Basic Physics	This experiment requires the use of ‘Using a Vernier’ (P00).
02	Determination of unknown masses by using the principle of moments	AS Unit 1.1 Basic physics
03	Measurement of g by freefall	AS Unit 1.2 Kinematics
04	Investigation of Newton’s second law	AS Unit 1.3 Dynamics
05	Determination of Young’s modulus of a metal in the form of a wire	AS Unit 1.5 Solids under stress	This experiment requires the use of ‘Using a Vernier’ (P00).
06	Investigation of the force – extension relationship for rubber	AS Unit 1.5 Solids under stress	This experiment requires the use of ‘Using a Vernier’ (P00).
07	Investigation of the I–V characteristics of a filament of a lamp and a metal wire at constant temperature	AS Unit 2.2 Resistance
08	Determination of the resistivity of a wire	AS Unit 2.2 Resistance	This experiment requires the use of ‘Using a Vernier’ (P00).
09	Investigation of the variation of resistance with temperature for a metal wire	AS Unit 2.2 Resistance
10	Determination of the internal resistance of a cell	AS Unit 2.3 D.C. circuits
11	Measurement of the intensity variations for polarisation	AS Unit 2.4 The nature of waves
12	Determination of wavelength using Young’s double slits	AS Unit 2.5 Wave properties	This experiment requires the use of ‘Using a Vernier’ (P00).
13	Determination of wavelength using a diffraction grating	AS Unit 2.5 Wave properties	This experiment requires the use of ‘Using a Vernier’ (P00).
14	Determination of the speed of sound using stationary waves	AS Unit 2.5 Wave properties
Physics 15	Measurement of the refractive index of a material	AS Unit 2.2 Wave properties
16	Determination of h using LEDs	AS Unit 2.7 Photons
17	Measurement of g with a pendulum	A2 Unit 3.2 Vibrations
18	Investigation of the damping of a spring	A2 Unit 3.2 Vibrations
19	Estimation of absolute zero by use of the gas laws	A2 Unit 3.4 Thermal physics
20	Measurement of the specific heat capacity for a solid	A2 Unit 3.4 Thermal physics
21	Investigation of radioactive decay – a dice analogy	A2 Unit 3.5 Nuclear decay
22	Investigation of the variation of intensity of gamma radiation with distance	A2 Unit 3.5 Nuclear decay
23	Investigation of the charging and discharging of a capacitor to determine the time constant	A2 Unit 4.1 Capacitance	Students must pay particular attention to correct connection of capacitors as they can readily explode if incorrectly connected.
24	Investigation of the energy stored in a capacitor	A2 Unit 4.1 Capacitance
25	Investigation of the force on a current in a magnetic field	A2 Unit 4.4 Magnetic fields
26	Investigation of magnetic flux density using a hall probe	A2 Unit 4.4 Magnetic fields

Please click here for the answers to the Physics questions.