Desirable or Not?

Why it matters

A banana turning golden and sweet is a change you welcome. The same banana going black and mushy a week later is a change you wish you could stop.

Predict first

Milk left in a warm kitchen turns sour and spoils. How would you describe this change?

Changes can be desirable (helpful, like cooking) or undesirable (harmful, like food spoiling). We try to speed up the ones we want and slow down the ones we do not.

• A desirable change we want to happen
• An undesirable change we try to prevent — correct
• Not a change at all
• A change that helps our food

What you do

Sort each change: is it a DESIRABLE change we want, or an UNDESIRABLE change we try to stop?

Check yourself

We deliberately add a little curd to warm milk to set fresh curd for the kitchen. This is:

Setting curd from milk is a change we deliberately bring about to make food we want, so it is a desirable change.

Rust slowly eats into an iron gate, so we paint it to keep the rust away. Rusting here is:

Rusting slowly weakens iron, so we paint or oil the metal to prevent it. It is a change we try to stop.

Rain is welcome for a farmer's dry field but a problem during a village fair. This shows that a change can be:

Whether a change is desirable depends on the situation. The same change, such as rain, can be wanted at one time and unwanted at another.

• A desirable change we want to happen — correct
• An undesirable change we try to stop
• Not a real change at all
• A desirable change we try to speed up
• An undesirable change we try to prevent — correct
• A change that makes the iron stronger
• Desirable at one time and undesirable at another — correct
• Always desirable, no matter what
• Never a real change
• Always undesirable, no matter what