Interested is a past participle. When used as an adjective it says how someone feels.
For example: "I was very interested in the lesson."
Interesting is a present participle. When used as an adjective it describes the people or things that cause the feelings.
For example: "It was an interesting lesson ."
Similarly, we say:
"I am very touched by the stranger's kindness." (touched: adj. emotionally affected; moved)
"His gratitude was simple and touching." (touching: adj. arousing affect)
The following exercise practices different forms with some command words.
Look at the sentences below and choose the correct word to fill the gap.
1. I am very ____ in the job that you are offering and would like to apply for it.
interest
interested
interesting
2. I want to study linguistics at university because language systems really ____ me.
fascinate
fascinated
fascinating
3. I find it very ____ that pollution is getting worse and governments are doing very little about it.
worry
worried
worrying
4. How can you like American sports? I can't watch them. They just ____ me to tears.
bore
bored
boring
5. In the middle of the flight we hit some turbulence and the plane dropped very quickly. It was so ____.
terrify
terrified
terrifying
6. Anthony was ____ to hear that he had passed the exam because he thought he had definitely failed.
amaze
amazed
amazing
7. Peter's a very ____ person to be with. You never know what crazy thing he's going to do next.
alarm
alarmed
alarming
8. You'd think that running a marathon would leave Abebe ____ but he's still doing exercises.
exhaust
exhausted
exhausting
9. My son has been very ____ at school. All the teachers say that he can do much better. He really needs to work harder.
disappoint
disappointed
disappointing
10. All the passenger were extremely ____ when they heard that their flight had been delayed yet again.
annoy
annoyed
annoying
Answers:
(1. intrested; 2. fascinate; 3. worrying; 4. bore; 5. terrifying; 6. amazed; 7. alarming; 8. exhausted; 9. disappointing; 10. annoyed)
Excercises source:
http://www.eflworksheets.com/onlineexercises/intermediate/vocabulary/interestinginterested.htm