We can use to + infinitive and for + noun to say what is the purpose of an action, or the reason why we do something.

to + infinitive

• I went to the grocery store to buy some vegetables. 
• I studied hard to pass the exam.

for + noun

• Let’s go to the pub for a drink. 
• We climbed to the top for the views.

Compare to vs for:

• I went to the shop to buy some milk. 
• I went to the shop for some milk. 

for + -ing

Don’t use for + -ing to talk about why we do something

We don’t use for + -ing to say what is the purpose of our actions, why we do something.

• I work hard for improving my English.
• I work hard to improve my English.
• Turn the TV on for watching the news.
• Turn the TV on to watch the news.

Use for + -ing to talk about the purpose or function of an object

We use for + ing to talk about the purpose or function of a thing, what an object is used for.

• This machine is used for cleaning cars.
• This is a special camera for photographing small objects.  

Expressing purpose with ‘to’ and ‘for’

Go to http://www.guardian.co.uk/travel/2011/feb/14/readers-tips-carnivals-around-the-world
Find the answers to these questions:

1. In Dominica, the carnival is a mix of two traditions. What are they?
2. What kind of battle do they have in the Nice carnival?
3. What do people sing about in the Cádiz carnival?
4. What do they bury in Ash Wednesday in Santa Cruz de Tenerife?
5. Which two instruments are played in the Fasnacht carnival in Switzerland?
6. Which town in Germany has straw bears in their carnival?
7. What kind of music can you hear in the Trinidad and Tobago carnivals?
8. What’s special about the giant heads in the Barranquilla carnival in Colombia?
9. What kind of fights do they have in the Oruro carnival in Bolivia?
10. How long does the Montevideo carnival last in Uruguay?