Youngsters from Oldfield School have been supporting homeless people as part of the Julian House Christmas Appeal.
Pupils and staff raised £220 for the appeal at the school's Christmas Festival last month.
The money will help Julian House towards the appeal target of £100,000, a third of what the charity needs to keep going each year.
A representative from the charity visited the school to talk to Year 8 and 9 pupils about its work.
They heard how Julian House tries to reduce the impact of homelessness on those affected, especially at this time of year.
Staff at the Manvers Street night shelter are clearing offices and the dining area so extra bed spaces can be made on the floor, in response to the cold snap.
Julian House fundraising manager Cecil Weir said he was shocked at the number of people sleeping rough in the city on a recent night-time tour.
To date the appeal has raised just over £81,000.
Mr Weir said: "On the current pattern of gifts the £100,000 target is going to be very tough.
"I would urge people to dig deep and think about the life saving services which Julian House has to provide now and for the rest of the year."
To donate to the appeal visit www.julianhouse.org.uk.
