Health and Well-being
The mystery of food
Explain what makes food spoil, say how drying, oiling, canning and cooling each stop it, and name the teeth that cut, tear, crush and grind.
A forgotten lunch box comes back three days later smelling foul, with coloured patches across the uttapam. Those patches are mould, and mould is a colony of thousands of microbes — living things far too small to see, which is why a microscope was invented to look at them. Microbes are in the soil, in water, in the air around us, in plants and animals, and inside us.
What microbes need
Microbes need three things to grow: moisture, air and the right temperature. Take away any one of the three and they are stopped in their tracks. That single sentence is the reason behind each way of keeping food that follows.
The same idea, four ways
Drying chillies in the sun takes the moisture away. Pouring oil over a pickle keeps the air out. Sealing food into air tight cans keeps the air out too. Putting milk in a fridge keeps it cold. Salt, sugar and spices such as pepper do the job the old way, and are used still.
Microbes are not the enemy
Some microbes spoil food; others make it. Microbes in the air make idli batter rise, and the small microbes in curd join the good microbes in your stomach and help you digest what you have eaten.
Have a play
One side of a jaw, from the front of the mouth to the back, with each group of teeth named.
Tap any part of the picture.
Worked example
A slice of bread left out for two days grows coloured patches, but a jar of pickle made two months ago is still good. Why the difference?
Write down what microbes need: moisture, air and the right temperature.
Spoiling is microbes growing. So the question is not really about bread and pickle — it is about which of the three the bread offers and the pickle does not.
Try it together
Work out why Amma dries the chillies in the sun before making them into powder.
The chillies go out on a mat on the balcony in the middle of the day, and Amma says the powder will last the family a year.
1.The Sun beats down on the chillies through the afternoon. Which one of the three things microbes need is being taken out of them?
Have a go
Have a go on your own. Disha's tooth aches and the dentist finds a hole in it. What is that hole called?
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.