Janet Chapman, of Church Way, Yealmpton, writes: Children love balloons and it might seem a good idea to use them in a geography project, but the teacher at Erme Primary needs to think about this a bit more. Some may well land locally and others further afield, but inevitably some will land in the sea, where they pose a risk of damage or death to several rare and endangered sea creatures. It is for this reason that the Marine Conservation Society launched its Don't Let Go ­campaign. Further information is available on the society's website at http://www.mcsuk.org">www.mcsuk.org. Sky lanterns are even more dangerous, as they can set fire to barns and buildings as well as injuring domestic, wild and marine life.