How volcano pumice helps scientists

Flights to the island of Tonga have been cancelled after a volcano erupted, spewing ash into the sky.

Tonga is a small island in the Pacific Ocean, east of Australia.

Experts from New Zealand's GNS Science agency said volcanic activity had been recorded for a few weeks.

It's thought the volcano may have started under the ocean but erupted out of the water, creating a tiny new island.

Airlines hope they can carry on sending planes to Tonga on Wednesday, as long as the ash has cleared.

Fierce Earth presenter Dr Dougal Jerram told Newsround that pumice stones from volcanoes help scientists investigate the eruptions.