This fun experiment will explain the concepts of density and buoyancy to your kid  

More often than not, scientific concepts tend to be better understood by kids when demonstrated through experimentation. Chemistry can be tricky for a few kids, but this fun DIY sugar water rainbow experiment will help your school-goer understand the concepts of density and buoyancy clearly. Not only is it informative, it is equally fun to perform as well. Read on to find out what materials you will need along with a detailed step-by-step procedure to perform this DIY experiment. 

What you will need 
Ask your budding scientist to help you gather these simple materials for the experiment. 

• Liquid food colouring (preferably in the shades of the rainbow) 
• 1 clear straw 
• Water 
• 6 transparent cups/ glasses 
• 1 tablespoon 
• Sugar 

Step-by-step guide to perform the sugar water rainbow experiment 
These are pretty simple steps. Help your kids follow these. 

• Line the cups and fill each of them with water. Less than half is ideal, and ensure that all the cups have the same amount of water. 
• Next, add a drop of food colouring to each cup. Ensure to assign a different colour to every cup, in the order of the colours of a rainbow. 
• Do not add any sugar to the first cup. 
• Add 1 tbsp sugar to the second cup, 2 tbsp to the third, 3 to the fourth one and so on till the sixth cup. 
• Stir each cup and ensure that the sugar has completely dissolved. 
• Next, create the sugar water rainbow by inserting the end of the clear straw only half an inch in the cup with no sugar (the first one.)   
• Ensure that the water from the straw does not fall out while removing it from the cup by covering its top with your thumb. 
• After this, dip the same straw into the second cup (the one with 1 tbsp sugar.) Insert this a little further, around 1 inch deep.  
• In a single swift movement, release the thumb and recap it yet again. This will leave you with two layers of colour. 
• Proceed with the same method for the other cups as well. Remember, each time the straw must be inserted half an inch deeper. 

What exactly is happening in this experiment? 
This experiment demonstrates how the concepts of density and buoyancy work. Density is the amount of mass of a substance within the volume occupied by an object. Buoyancy is the upward force which a fluid exerts which opposes the weight of an object which is partially or completely immersed in it. It is determined by relative density. Here, the cup with more sugar is denser than the cup with less sugar. Hence, it is seen that the solution with less density floats above the one with higher density, ensuring that the colours do not mix.