PRESENTATION OUTLINE
Separating Insoluble Substances
Extracting Liquids ~
To extract liquids, the object (usually food) is squeezed until the volume of the object becomes smaller. To make the volume smaller, the liquid in the object is squeezed out, and the solid that is left becomes denser.
In everyday life you would use this method to:
~ make juices
~ extracting oils for cooking
~ getting rid of fatty juices in meat
This method is especially important whilst cooking.
Another simple example is removing water from a sponge.
Sieving ~
Sieving is used for washing and draining objects (mainly food). Sieving is used by flushing out all of the unwanted grime, for example, washing strawberries with water to get rid of all of the germs, and then draining all of the water (cleanser) out.
In short, the water takes all of the germs and dirtiness from the strawberries, and then the germs get washed away with the water.
Everyday life uses for sieving:
~ washing vegetables and fruit
Gravity Separation ~
This method uses gravity to separate substances.
For this to work, you need to put heavier and lighter objects in liquid, and the heavier objects will fall to the bottom, and the lighter objects will rise to the top.
What this method is used for:
~ panning for gold
~ when sorting mixed weight objects, for example, screws, nuts, bolts, nails.
~ separating oils from water, for example, removing fats from meat during the cooking process
Filtration ~
This method is similar to sieving, but often used for separating smaller particles.
First, the smaller and bigger particles get put into a container, with tiny holes in it (sometimes microscopic).The smaller particles are able to get sucked or drained through the tiny holes, but the bigger particles can't fit. This leaves a filtered group of smaller particles, and the bigger particles remain. They are now separated.
Examples of when this method is used:
~ vacuuming, removing dirt and dust particles
~ air conditioning and heating, removing dust particles
~ water filtration, removing dirt, bugs, dust particles
Centrifuge ~
The centrifuge method of separating substances works by using a spinner.
Wet objects get placed in some sort of spinner with little holes in the sides. The spinner spins so fast, that the liquid from the wet object is forced out through the holes, draining the wet object.
Examples of when this method is used:
~ clothes being spun and drained in a washing machine
~ salad spinners
Evaporation ~
Evaporation separates solids or liquids from gases.
Evaporation is the process in which heat transforms liquids or solids into water vapour.
Water vapour is a gas formation of water, therefore heat changes solids and liquids into gas.
Examples of when this is method happens:
~ whilst boiling the kettle, heat changes the water into steam
