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Use and benefits of technology in the home. Technology has : Reduced the workload in the home Reduced the time needed to carry out household tasks Increased efficiency in the home Improved communications and security in the home Provided more durable and hygienic surfaces and materials.
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Use and benefits of technology in the home Technology has: • Reduced the workload in the home • Reduced the time needed to carry out household tasks • Increased efficiency in the home • Improved communications and security in the home • Provided more durable and hygienic surfaces and materials.
Technology in the home Technology has impacted: • Food preparation • Cooking • Food storage • Cleaning • Laundry • Household surfaces • Entertainment • Automation • Communications • Security • Management • Garden and DIY.
Selecting household appliances Things to consider when choosing a household appliance: • Cost • Brand name • Safety • Energy efficiency • Needs of the individual or family • Space available • Design • Construction • Ease of cleaning • Guarantee and aftersales service.
Categories of appliances There are three categories of household appliance: • Appliances with a motor • Appliances with an element • Appliances with a combination of a motor and an element.
Kettle A kettle is a small appliance with an element that is used to heat water to boiling point quickly and efficiently. • Role of a kettle: • Boiling water – kettles boil water fast and has water level indicators to measure the water • Reduces workload, little effort required • They can often add to the aesthetic appeal of the kitchen • Portable – kettles can be moved from one place to another without a major risk of burning.
Design of a kettle • Kettles are made from a number of materials including stainless steel, plastic and copper. • Kettles are available in a variety of colours which allows colour co-ordination with other appliances in the kitchen. • A heating element is found inside the base of the kettle. • All kettles have a maximum and minimum water level. • The handle is manufactured from a heat-resistant material. • Most contain a thermostat that automatically turns off the kettle when it boils.
Working principle of a kettle • The kettle is plugged in and the electricity flows to the element. • The element offers resistance, causing it to heat. • The heated element heats the water by conduction, and convection currents are sent up through the water. • When boiling point is reached, the thermostat automatically switches the kettle off.
Group work • You are moving away to college and are going to purchase technology for your new house. • When buying a kettle, what factors are you going to consider before you purchase it? • Why are these factors important when purchasing your kettle? • Discuss these in groups and create a checklist to take with you when shopping for a kettle. • In your groups, discuss why it is important to follow guidelines for using the kettle.
Caring for your kettle • Use only for water. • Unplug before cleaning. • Clean filter regularly. • De-scale regularly if necessary. • Never immerse in water. • Clean the outside with a cloth. • Avoid using abrasives on the outside.
Food processor A food processor is a small appliance with a motor. • Role of a food processor: • They make the preparation of foods much easier • They can reduce time and energy in the preparation of many dishes, e.g. chopping for soup • They are easy to use and maintain.
Design of a food processor A food processor is made up of a base unit that contains: • The motor, housed in a strong metal plastic casing • A flex and a three pin plugs which bring electricity to the appliance • A control switch with various speeds, including a pulsating speed, is found on the plastic casing. It also has a bowl unit that contains: • A transparent plastic or metal bowl with a lockable funnelled lid that sits on a spindle • A feed tube and food pusher that also measures ingredients. Food processors also come with a variety of attachments.
Attachments for a food processor • Steel chopping blades • Whisks • Grating disc • Slicing disc • Chip disc • Dough hook • Juice extractor • Liquidiser
Working principle of a food processor • A blade or disc is placed on the spindle. • The food is placed in the bowl and the lid is locked into place. • If the feeder funnel is being used, the lid is locked into place where the food is fed through the funnel. • The food processor is plugged in and the motor, which is powered by electricity, causes the spindle to rotate. • There are a number of control speeds on the casing. • The majority of food processors have a capacity of 2 litres. However, different sizes are now more readily available.
Guidelines for the use of a food processor • Always follow the manufacturer’s instructions. • Ensure attachments are fitted correctly. • Follow basic hygiene guidelines when preparing food. • Dry hands thoroughly. • Never place metal cutlery or fingers in the feeder funnel when the disc/blade is rotating. • Do not overload the bowl with food. • Stop the machine occasionally and scrape down the sides of the bowl.
Guidelines for the care and cleaning of a food processor • Always unplug the appliance before cleaning. • Wash all removable parts in hot, soapy water and dry thoroughly. • Be careful when removing, washing and drying the blades or discs. • Never immerse the motor/plastic casing in water. • Clean the outside and the flex with a warm, damp cloth. • Place the dismantled food processor in a well-ventilated cupboard to allow good air circulation. • Store with the lid off to allow air to circulate.
Refrigerator A refrigerator (or fridge) is used to keep perishable foods fresh for a specific length of time in cold conditions, which inhibits the growth of micro-organisms. Types of refrigerator: • Standard fridge – separate ice box, star rating * or **, variety of shelves • Larder fridge – no freezer compartment • Fridge freezer – fridge and a freezer in two separate cabinets (with separate doors).
Design of a refrigerator • An outer casing of enamelled steel and moulded polystyrene for the interior of the door. Insulating material is placed between them. The door has a rubber gasket and magnetic strip that forms a seal when the door is closed. • A thermostat controls the temperature. • A light automatically switches on when the door opens. • The inside contains a number of glass/plastic shelves. One or two plastic vegetable drawers are at the base of the fridge, and the door contains adjustable bottle holders, cheese and egg compartments. • Most fridges have an ice box at the top of the fridge.
Modern features of a refrigerator • Different colours, finishes, designs and materials used. • Zoned refrigerator – different parts have different temperatures. • Chilled drinks/ice dispenser. • Tall bottle shelves. • Large American style/retro style refrigerators are popular. • Integrated doors to blend in with kitchen cupboards. • Automatic defrosting/frost-free fridges. • Digital temperature displays.
Working principle of a compressor refrigerator • The liquid evaporates and draws heat from surrounding area, cooling it. • The compressor contains gaseous refrigerant, i.e. Freon 12. • The compressor is turned on by the motor, it forces the refrigerant into the condenser. The condenser cools it and changes it to liquid. • The liquid refrigerant passes into the evaporator, where it is cooled and evaporated into a gas by taking the heat from the fridge cabinet, thereby keeping it cool. • The refrigerant returns to the compressor and the cycle restarts. • A thermostat controls the temperature by disconnecting the motor when the fridge temperature is between 1°C and 4°C, and reconnecting it when the temperature begins to rise.
Guidelines for use of a refrigerator • Avoid opening it unnecessarily, as this raises the temperature and puts pressure on the motor. • Cool foods before placing in the fridge. • Cover foods in the fridge. • Store raw fish/meat below cooked food or dairy products. • Use food in rotation to prevent wastage. • Do not overpack the fridge. • Thaw frozen foods in the fridge. • Check the temperature inside the fridge regularly.
Guidelines for the care and cleaning of a fridge • Never place the fridge near a heat source. • Defrost regularly. • Dust regularly and allow for sufficient space for air circulation behind the fridge. • Clean interior weekly – wipe up spills immediately. • Use a damp cloth in hot soapy water to clean exterior and seal. • Wash the interior with warm water and bicarbonate of soda; avoid using strong-smelling detergents. • If not in use, leave fridge unplugged and clean, with the door open.
Star rating Every fridge has a star rating. This indicates the temperature of the ice box.
Microwave oven There are three main types of microwave: • Conventional microwave used for cooking, reheating and defrosting • Combination microwave combines oven, grill and microwave; can brown food • Microwave with grill cooks, reheats, defrosts and browns food.
Design of a microwave • A metal-lined steel box with an enamelled exterior. • A glass door with a perforated metal layer to redirect the microwaves back into the oven. • A seal to prevent microwaves escaping, and a safety lock on the door that turns the oven off when it is opened. • A manual/digital control panel with an on/off switch, timer, defrost facility and programme settings. • A light inside the oven illuminates the food during cooking. • A flex and a plug. Enclosed in the metal casing is: • A magnetron, which converts electricity to microwave energy. • A transformer, which increases the domestic voltage. • A wave guide/stirrer, which distributes the microwaves evenly. • A glass turntable to ensure the even cooking of the food.
Working principles of a microwave • The microwave oven is plugged in and turned on. • The transformer steps up the standard voltage. • The magnetron coverts electricity to electromagnetic energy (microwaves). • The microwave/electromagnetic energy travels into the oven space via the wave guide. • The wave stirrer or turntable directs the microwaves around the oven.
Working principles of a microwave • Waves are: • Reflected off the walls • Transmitted through containers • Absorbed by food as it cooks. • The microwaves will penetrate the food to a depth of 5 cm. • The water molecules absorb the microwave energy and vibrate at high speed (2,45 GHz per second) this causes friction, which creates heat and thereby cooks the food by conduction. • Food cooked in the microwave does not colour, so a grill can be used to brown the food.
Guidelines for the use of a microwave oven • Follow the manufacturer’s instructions. • Never turn on the microwave when it is empty. • Never place metal or metal trim containers or dishes in the microwave oven; use appropriate cookware made from paper, glass, plastic and ceramic. • Stir liquid foods occasionally during cooking to prevent hot spots in dishes. • Cover food with cling film or kitchen paper to help retain moisture and speed up the cooking time. • Arrange foods in a circle to ensure even distribution; cook small amounts of food. • Allow foods to stand for the recommended time after cooking.
Guidelines for care and cleaning of a microwave • Follow the manufacturer’s instructions. • Always unplug the microwave before cleaning. • Avoid moving the microwave oven as it may damage the magnetron. • Do not open the door of the microwave while it is still on as it could blow a fuse. • Wipe up spills immediately. • Remove the glass turntable and clean regularly. • Wipe the outside of the oven and the rubber door seal with a damp cloth wrung out in hot soapy water. • Avoid using harsh abrasives. • If any fault occurs get a qualified person to rectify it.
Modern features of a microwave • Variety of types, sizes and colours. • Digital/electronic displays for timing and functions. • Defrost settings. • Combination ovens – the electromagnetic waves cook the food quickly and it is browned and crisped by the grill or oven. • Steam injection used in some modern microwaves to keep food moist.
Key words for revision • Appliances • Automatic • Compressor • Condenser • Defrost • Element • Evaporator • Heating • Magnetron • Motor • Refrigerant • Structure • Technology • Thermostat • Transformer • Turntable • Wave guide/stirrer • Working principle
