1. Contrasting SER and ESTAR
Changes in meaning…

2. In general we know that using…
SER
denotes a more or less permanent state, expressions for time, origin, location of events and identifying descriptions.
ESTAR
denotes, current and/or resultant states, location of nouns, and actions in progress; “the effect of the cause”

3. However… SER and ESTAR are not mutually exclusive…
That is, with certain adjectives both SER and ESTAR can be use along with it.
The result is that the adjective takes on different connotations depending on the verb that precedes it.

4. Examples… SER ESTAR El hombre es aburrido. The man is boring.
El hombre está aburrido.
The man is bored.
Ella es lista.
She is clever.
Ella está lista.
She is ready. (prepared)
El café no es bueno.
Coffee is not good. (unhealthy)
El café no está bueno.
Coffee isn’t good. (tastes bad)

5. More examples… SER ESTAR Eres muy bonita. You are pretty.
Estás bonita.
You look pretty. (today)
Ella es fea.
She is ugly. (personality)
Ella está fea.
She looks ugly.
Somos divertidos.
We are funny.
Estamos divertidos.
We are amused.

6. More examples… SER ESTAR Eres muy guapa. You are good looking.
Estás guapa.
You are good-looking. (today)
La manzana es verde.
The apple is green.
La manzana está verde.
The apple is not ripe.
Somos vivos.
We are smart.
Estamos vivos.
We are alive.

7. Describing food…
When describing food using SER and ESTAR becomes a little tricky.
SER + adjective
describes inherent or naturally occurring qualities.
ESTAR + adjective
describes qualities not naturally occurring or resultant qualities

8. Examples… SER ESTAR La toronja es agria. The grapefruit is sour.
La salsa está agria.
The sauce tastes sour.
El jalapeño es picante.
The jalepeño is spicy.
Las patatas están picantes.
The potatoes taste spicy.

9. The past participle The past participle can be used as an adjective.
They usually are preceded by ESTAR, because they describe current condition.
When this occurs the past participle must agree with the noun it is describing.

10. Examples… ESTAR El proyector está roto. The projector is broken.
(ROMPER = roto/a)
La cámara está rota también.
The camera is broken too.
Ella está cansada.
She is tired.
(CANSAR = cansado/a)
Ellas están cansadas también.
They are tired too.

11. Some past participle/adjectives and their infinitives
ABURRIRSE
  aburrido/a
  bored
CANSARSE
  cansado/a
  tired
CASARSE (CON)
  casado/a (con)
  married (to)
ENAMORARSE
enamorado/a (de)
 in love (with)
PREOCUPARSE
preocupado/a
 worried
ENOJARSE
enojado/a
Angry
OCUPARSE (DE)
 ocupado/a
busy
ENFERMARSE
  enfermo/a
 sick
ENTRISTECERSE
 triste
  sad

12. Pitfalls…
Not all adjectives can be used interchageably with SER and ESTAR.
Be careful of what you mean to say when using adjectives with SER and ESTAR.
There are special circumstance when describing food.
Make sure all adjectives agree.