CT 108: SCIENCE AND MATHEMATIC TEACHING METHODS:
ORGANIZING PRACTICAL AND LABORATORY ACTIVITIES
BY KAFYULILO AND MWANYIKA
LABORATORY MANAGEMENT What is a laboratory? Discussion!
Laboratory management It is mostly concerned with the provision of materials for laboratory work maintenance and repair of equipment and the proper organization of the laboratory and auxiliary services.
The teaching laboratory may consist of the common preparation room and the dispensing store.
What is a preparation room? This refer to a room which provides space where solutions and equipments can be prepared for use. The preparation room must contain the following: A sink and a drawing board A water still or deioniser A balance (preferably two, an accurate one and rough one)
Large bench for dry works.
What is a dispensing store? This is a room where a teacher can store the materials and equipment in everyday use and to provide a room where some of the items which may be dangerous could be properly stored.
The materials kept in the dispensing store must be arranged in a way that makes it easy to find any particular item without relying too much on memory.
Dispensing store (cont) For the purpose of reducing inconvenience which may result from misplacement, it is recommended that you have a label of the arrangement of all materials in the store.
All hazardous chemicals should be put in a cupboard which should always be locked except in times of need and a large label should be put on the door, indicating the dangers of contaminating those chemicals.
STORAGE OF APPARATUS Storage of apparatus is highly linked to the climatic condition of the area concerned. Humid, hot conditions, produces rapid corrosion problems with ferrous. Hot dry conditions, creates the hazard of dust and send accumulations in the laboratory equipments. Cold conditions, most preferred.
Change of humid levels between the preparation room and the laboratory could be detrimental to some of some of the apparatus.
How to overcome the unfavourable conditions for equipment storage. Use a moving air current in a cupboard eg. Use of small fan. For this to be successful, the shelves should be of slated type to allow air movement. Use an electric bulb in the bottom of the cupboard to set up convention current. Drill holes about 2cm in diameter at each end or the cupboard. Holes can be covered by fine gauze to prevent dust
Ensure good air circulation in the preparation room
How to overcome….. (cont)
Windows should be covered with fine mosquito netting to keep out flying insects, lizards and crawling insects.
STORAGE OF CHEMICALS Chemical storage is one of the school’s main problem. Mostly this is because of ignorance e.g. buying too much chemicals. Resist the temptation of buying far more than it is needed.
Discard any stock which shows the least sign of deterioration.
How to ensure proper storage of chemicals? Chemicals which can decompose slowly with the evolution of gas e.g. hydrogen peroxide or hydrochlorite, must be stored in dark bottles with some kind of vented stopper. Bottles of chemicals liable to hydrolysis, e.g. silicon tetrachloride, calcium carbide or phosphide etc, should have original stoppers, or fitted with a kind of bunsen valves.
All reagent containers should be of such a size that they can held easily and should be at bench height.
How to ensure…. (cont) Large bottles should never be lifted by the neck, the use of special bottles carriers is recommended. All chemicals containers should be clearly labeled at all times. Keep organic and inorganic chemicals separately.
Highly reactive reagents should not be placed adjacent to each other.
How to ensure…. (cont) Chemicals presenting special hazards should not be kept on the open shelf but in special cupboards. Special attention should be kept in the following; Scheduled poisons should be kept under lock and key in a proper poison cupboard.
Radioactive substances must be kept in a locked and marked cupboard.
Special attentions…. (cont) Concentrated acids and alkalis should be stored at floor level. Highly flammable/inflammable liquids should be kept in a specially constructed store. This store should have; A brick-built cupboard against an external wall inside the main chemicals store and should have the vent to the outside.
Volatile and hydrolysable substances such as bromine should be kept in special cupboard. It is advisable that they should be kept away from sodium etc.
Conclusion In all procedures of laboratory management the maximum good housekeeping is paramount. Good house keeping involves cleanliness, tidiness and all things in their correct places at the start and finish of each day.
Proper labeling is essential. Pay attention to the labeling of bottles, jars and other containers which are used for chemicals and biological materials. Unlabeled chemicals are very dangerous and should be avoided at all cost.
STORAGE OF CHEMICALS IN THE PREPARATION/STORE ROOM Containers should be located alphabetically and stored by using their proper names, example ‘NaCl’ and not ‘salt’.
Have a small amount of prepared reagent ready for use in the classroom. Close to the storage area, there should be a wall chart which contains information on safety procedure and hazards.
Storage of chemicals…. From the prepared stock solution, students will get the appropriate quantities for investigations. So avoid to have a reagent bottles racks on the work benches. Lockable cupboards should be used to store poisonous and dangerous materials
Liquid chemicals in larger containers should be stored as low as possible
Storage of chemicals….. Glass ware should be stored in bays, with each size and type clearly labelled. For safety purposes, as well as to save space, glass tubing should be stored vertically in a suitably constructed rack. Biological specimens should be preserved in a sealed jars of varying size.
Bottles with dangerous liquids should be carried using a plastic bucket.
STORES MANAGEMENT The primary objectives of a science store is; Ensuring the availability of chemicals and equipment when needed.
Maintaining accurate records and provide management data
Organizing the science store There are two points to take in mind in organizing a science store; Economy –the store must provide the service economically Classification and identification Classification refers to the specialization of the compartments, cupboards, shelves, bays etc according to their contents. E.g chemicals
Identification refers to the process where the type of a stock is systematically defined and described by a system of coding.
Organizing the …. In identification the code should be used on all records. Receipts- there should be a system of accepting all materials, equipment and chemicals. Issue- you should have a record for all item that have been handed over to users.
Stock records- make sure that there is a record of all receipts, issues and balances of stocks.
Stock taking, stock checking, stock audit and stock level Stock taking: refers to physical verification of quantities and conditions of goods, on a periodical basis Stock checking: this is similar to stock taking but this may be done in adhoc basis for operational basis
Stock audit: refers to the invitation of an external agency to verify the stock materials.
Stock levels… The stock level in the laboratory should be maintained at optimal. Too high level of stock can lead to greater risk of deterioration Too low level of stock may endanger supplies needed immediately for use. The impact of too low or too high stock levels
Minimum and maximum reorder level: fixing the stock below which it would be dangerous to handle or fixing above which it would be uneconomical to store.
Too low and too high level…… Lead time: time taken for delivery. Reordering must be made before the minimum level is reached because of the time taken for delivery.
Deterioration risk: the stock should ensure availability of all items required but you should not allow large surpluses of stock to accumulate. Because soon they might deteriorate.
Too high and too low….. Risk of obsolescence: equipment, chemicals, and specimens stored too long, may become outdated.
Price movement: if there is a price fluctuations, you have to time the stocking of the materials for laboratory.
Store layout Appropriate storage: small items should be in bins, related items just adjacent, and large ones in the cupboards.
access: goods in bins should be at suitable height for easy withdrawal and filling.
PURCHASING LABORATORY MATERIALS Purchasing of the laboratory materials should be done by the person who is familiar with all the laboratory equipments. In purchasing laboratory equipments one is to keep in mind the following; Knowledge of the supplier Self knowledge of each laboratory item
Seek quotations from various suppliers
Purchasing…. Specification e.g. of time and quantity
Administration, e.g. checking the item delivered, certifying invoices for payments, legal etc.
PURCHASING POLICY Buy at the lowest price without sacrificing the quantity. Buy at right time to take advantage of price movement Use the most appropriate buying methods
Buy the most appropriate amounts
Purchasing routine Using a requisition forms Using a standard order forms to suppliers Goods received should be checked and recorded accordingly Invoices should be checked to ensure that the right price have been charged.
Make follow-up to ensure that goods are received on time.
Storing procedures Ensure proper records of both in and outgoing items from the laboratory. On accepting items for storage have; The stock records; this can give the running total Bin cards; contain similar information to that of stock records.
All items getting out of the store should require a requisition form.
Stock taking Account must be taken for stock in hand. To estimate the value of the items in the stock To detect the deteriorations Stock taking can be done annually or perpetually
The important thing is to know what to stock, how to stock, when to record and how much to record. In this case you can divide the stock into working and bulky stock
A bin card Bin cards contains all the information required for an efficient and simple methods of stock control.
Bin cards contains the following details;
Bin cards….. Details of items received or issued From whom they are received or to whom issued Invoice No/requisition No/order No
The balance held in stock
BINCARD Serial No…… Issuing unit:….. Stock at hand Qn. issued Qn. received Invoice Qn. ordered Detail Date
Name of item……. Min stock……
Receipts of goods Check if there is any broken item Check the receipts in relation to the delivery note Enter data into the order book details Tell the suppliers about any breakages Endorse the delivery notes
Re-pack goods if they are to be kept
Planning laboratory works Laboratory work involves, preparation of experiments and demonstrations. Neither of these can be done in a hurry. A reasonable amount of time is needed Full detail of what is required must be given Day requirements should be entered in the dairy, example;
Date and which class, practical time and place, list of requirement and their amounts.