Milk Rangoli: A cool home experiment to teach the concept of molecules
Science surrounds us in life, and can be illustrated in beautiful ways. For example, a walk in the garden can explain photosynthesis better than reading a book. As parent, you may have explained the concept of molecules to your kid. While text book diagrams help, an experiment to see how molecules behave in real life is a better way to remember a lesson. Try this experiment. First demonstrate it, and then read out the concepts we have explained below the experiment.
What do you need to do the milk rangoli experiment?
Most of these would be at home, so you don’t need to buy anything:
- A medium sized bowl
- ½ cup of milk
- Dishwashing soap
- Cotton ear bud
- 3 or 4 types of food colouring, you can add more if you want a very colourful rangoli
How will you create milk rangoli?
Assemble everything in the kitchen and then call your children over. Here’s the experiment step by step. Ask your kids to watch carefully as you do it.
- Pour the milk into the bowl and allow it to settle
- Add a drop of each food colour chosen in the centre of the bowl
- Dip the cotton ear bud into the centre of the milk, without stirring. Just touch the tip. The colours start moving out a bit
- Now smear some dish soap on the dry end of the ear bud. Place this soapy end back in the middle of the milk, and keep it there for 10 to 15 seconds
- The colours will burst into swirling patterns in the milk bowl, forming their own rangoli!
- Repeat the same thing with more soap on the ear bud. The colours continue their rangoli dance even after the bud is removed
How did the milk rangoli happen?
Milk is made up of water, vitamins, minerals, proteins, and fat. Fat and protein molecules are extra sensitive to changes in the surrounding. Dish soap weakens the chemical bonding that holds proteins and fats together in milk. The fat molecules dash out to join the soap molecules in a dance, and this action is visible because of the food colouring. Molecular movement makes up our world. This simple home experiment makes it magically visible.