Mixing Substances (Year 3)

Properties of Substances

Different substances have different properties. There are quite some substances that we use in our daily life, to name a few, salt, sugar, milk powder, baking powder and wheat flour. Properties of different substances can be stated in terms of:

Mind Map on Properties of Substances

• appearance
• smell
• feel
• colour
• whether the substances can be dissolved in water and/or vinegar

Unsafe Substances

Some substances around us are unsafe, for examples, bleach liquid, insecticide, liquid paper, detergent and cough syrup. These unsafe substances  are usually packed in containers/packages with labels and symbols.

Labels

• provide much of the information you need to know on how to use the substances safely

• may use signal words to show how toxic or hazardous (involving risk and danger) the substances can be either: 

'Danger' means it is the most hazardous kind of material

'Warning' is less hazardous than Danger, but more hazardous than Caution

'Caution' is the least hazardous rating 

Mind Map on Unsafe Substances' Symbols (Year 3)

Symbols

• show the harms that may be caused by the substances 

• are one of the key elements of a safety label

• have the ability to communicate across language barriers

There is always a need for kids to ask an adult before touching, smelling or tasting any unsafe substances. The unsafe substances should  be kept away in a place that is not reachable by kids. For adults, always look and read the labels or directions of usage carefully before handling any substances. It is better to be safe than sorry.

Separating a Mixture

What is a mixture? A mixture is two or more different substances physically blended together. There are several ways and techniques to separate a mixture, but in this post we only talk about the following methods:

• magnetic attraction - using a magnet to attract magnetic substances from other non-magnetic substances

Mind Map on Mixtures Separation Methods (Year 3)

• sieving - using sieve to sieve through fine substances and retain substances with bigger particles in the sieve

• sink and float (by picking) - using a basin of water to separate light substances (which will float on water) and heavy substances (which will sink in water)

• filtration - using a filter paper to separate substances from a liquid (water) in which the substances is insoluble

• evaporation (heating under the sun) - used to separate a solute from a solvent in a solution

 

Meanings of the following words will come in handy:

• solute - the substance that dissolves
• solvent - the liquid that does the dissolving
• solution - composed of a solute and a solvent
• residue - the insoluble solid trapped in the filter paper
• filtrate - the liquid that passes through the filter paper