chemistry experiments for children

food. But first, the minerals andwaterin the soil, the oxygen webreathein,
and the food we eat have to be dissolved. The process by whichourbodies
dissolve the food we eat isdigestion.
When solidparticlesfail to dissolve in a liquid, they form asuspension.When
solid particles seem to dissolve in a liquid,butthe"solution"lacks theproperty
ofbeing able to pass througha membrane,it isnotreally asolution, buta
colloid.When two liquidsdon'tform a single clear liquid, they form anemulsion.
Colloidsand emulsions are kinds ofsuspensions.
The ability ofone substanceto make anothersubstance dissolve in it is
veryimportantto the cleaning industry.No amountofsoap and waterwill
removepaintstains or chewing gum. But if thecleanerknows what caused the
stain, he can remove it with thepropersolvent.

WHAT HAPPENS WHEN YOU MIX ASOLID AND ALlQUID

Gather these materials:Sodiumchloride (NaCl); talcumpowder; copper

sulfate (CuS04); garden soil; sucrose (C12H22011); potassium aluminum

sulfate (AI2(S04)3.K2S04); 5 pieces of filterpaper;5 homemadefunnels or I

regularfunnel; 10 test tubes; a test tuberack; some warm water; and an

alcoholburner.

Follow this procedure: Label 5 test tubes I to 5 or labeltheirplaces in the

testtuberack. Fill these 5 test tubes halfway with warm water.Put!teaspoonful

ofsodiumchlorideintothe first test tube, 1-teaspoonfulof talcum powder

intothe second, and so on, for the next three substances. Do not use the

potassiumaluminumsulfate yet.Ifthesubstancedoesn'tdissolve right away,

heat the testtubeover thealcoholburneruntil it does, or until you are sure it

won't.Makeouta datasheet similar to this one:

Numberof

Test Tube

Substance Put Appearance Appearance Appearance

into Test Tube Before Heating AfterHeating After Filtering

Arrangea funnel lined with filterpaperin each of theremaining5 test tubes.

NowOneby one, filter the"solutions"bypouringthemthroughthe funnel into

the different test tubes. If you use only one funnel, place it in theremaining

5 test tubes, one after theother,and be sure to use a fresh piece of filterpaper

every time. Fill in thedatasheet. Rinseoutthe test tube in which you first put

thegardensoil. Add a smallquantityofpotassiumaluminumsulfate to the test

tubecontainingthe filteredgarden-soil"solution"and filter it again into the

test tube you rinsed out.