Ponerse can be used to indicate changes in mood, physical conditions and appearance, voluntary or involuntary, which are usually short-lived, e.g. ponerse enfermo/a (to get ill), ponerse furioso/a (to get very angry), ponerse contento/a (to become pleased), although there are exceptions. There is sometimes some overlap with quedarse and volverse.
1. Ponerse, when implies a change, can have living subjects and also certain kinds of non-living subjects, like prices, food-stuffs, situations and, in some cases, weather conditions.
Cuando se enteró se puso muy contenta (when she heard about it she become very happy).
Carmina se puso ronca de tanto hablar (Carmina got hoarse from talking so much).
La paciente se puso mejor de su enfermedad (the patient’s better from her illness).
La situación se ha puesto insoportable (the situation has become unbearable).
El pescado se ha puesto malo (the fish gone bad).
Se está poniendo nublado (it is getting cloudy).
Most of the time there are pronominal verbs with the same meaning:
Alegrarse (to cheer up to be happy) = ponerse contento.
Enfermar (to get sick) ponerse enfermo.
Enronquecer (to get hoarse) ponerse ronco.
Mejorarse (to get better) ponerse mejor.
Estropearse (to go bad) ponerse malo.
2. Ponerse is often used with children to indicate that they are looking bigger or more handsome than ever:
¡Pero que guapo y grande se ha puesto este niño! (hasn’t this child got handsome and big!)
3. Ponerse a + infinitive means to begin:
El bebé se puso a llorar (the baby began to cry).
¡Ponte trabajar ahora mismo! (start working right now).
Nos pusimos a hablar de la muerte (We started talking about death).
4. Ponerse can also be used with a piece of clothing meaning to put on:
El niño se puso el pijama y se acostó (The boy put his pajamas on and went to bed).