It is a question many teachers have been asked by their pupils. Why do they need to listen to a teacher at all when they have Google?
This Saturday is World Teachers' Day and the changing nature of the profession will come under scrutiny at a festival at the Royal Hospital in Kilmainham.
The Teaching Council, which is organising the festival known as Feilte, is hoping to show the profession in a positive light.
The event is focusing on teachers who are involved in innovative learning projects. But the festival may be overshadowed by the ongoing troubles over the Haddington Road Agreement on pay and conditions.
Teachers have been hit by pay cuts, increasing class sizes and diminishing resources. Morale may be low, but a growing population of children will ensure that there is no shortage of job opportunities in the future.
Regardless of the cuts, education researcher Dr Gerry Jeffers, an authority on innovation in education, says the role of teacher has changed dramatically.
"They say a teacher is no longer a sage on the stage, but a guide on the side," he says.
"The teacher is no longer the fount of all knowledge when students can look up information on Google, but their role is no less important."
As one principal put it, instead of imparting knowledge, teachers will give their students guidance on where to find it, how to use it and apply it, and how to be creative with it.
"Learning how to learn is more important for students than knowledge of content itself," says Dr Gerry Jeffers.
Twenty years ago a teacher could enter the profession without any technical prowess, apart from possibly plugging in a primitive overhead projector.
Gerry Jeffers says teachers have to be technically proficient to operate the interactive whiteboards that are becoming the norm in classrooms.
But if the screen goes blank and they are at a loss what to do, at least their pupils might be able to put them right.
'The young teachers coming out of education colleges are digital natives and are comfortable using new technology," said Gerry Jeffers. "Nobody taught them how to use their mobile phones or Facebook.
"They are illustrating their classes with YouTube clips."
Dr Jeffers, a former National Co-ordinator of transition year, says teachers are moving far away from the old idea of chalk and talk with an authoritarian figure standing at the head of the class.
"The most dramatic change will be the introduction of the new junior cycle curriculum next year. It has generated the same sense of fear and excitement as the introduction of transition year 20 years ago."
There will be much less focus on preparing students for final exams in the early years of second-level school.
Teachers will play a key role in devising courses and assessing their own students, and there will be a greater emphasis on projects and less boundaries between subjects.
"Teachers will be able to offer courses that are relevant to a particular area with short courses," says Gerry Jeffers. "For example, if you are in Clare you could have a course in Burren studies."
"There's much more teamwork now between teachers, and also with other staff," says Susan Gibney, principal of Queen of Angels Primary School in Sandyford, Co Dublin.
"We would be working with special needs assistants and collaborating on projects. If you had two teachers who both teach fourth class, they could both use the same Powerpoint presentation."
Mary O'Donovan, director of the West Cork Education Centre, says it is a much less isolated profession than it once was.
"Teachers are much more involved in sharing information and discussing what works best," she says
Ms O'Donovan is involved in setting up Learning School Projects, where groups of facilitators from Education Centres support schools in aspects of their work.
A group of teachers in a school might be given support in improving numeracy and literacy with a group of targeted students.
Technology may come and go, but some of the skills needed to be a teacher remain constant, according to Mary O'Donovan.
"You still need to be able to tell a story and inspire enthusiasm in the students," says Ms O'Donovan.
"To be a good teacher you need three essential qualities," says Dr Gerry Jeffers. "You have to make sure your classes are relevant so that you can connect with the students you are teaching.
"Secondly, you have to challenge them, and thirdly you have to ensure that you foster imagination."
To coincide with World Teachers' Day, the EU has launched a new initiative, Opening up Education. The project aims to enable both teachers and students reap the benefits of the digital revolution. Its openeducationeuropa.eu portal provides free-to-use materials. Teachers and students can explore the resources either together or on their own