S4·E13 Hearth and Home

Sara and Felix are desperate for a science project for school, when they find perfect one in Jasper's work room. Aunt Eliza surprises everyone with a visit. Since it is cold, and lambing time, the visit is not welcome. Janet and Alec, tired and worn out, make some unkind remarks about Eliza and she runs away. The science project warms up a frozen Eliza, a cold barn and keeps the new born lambs warm, as well. [I guess this disproves my favourite quote of the episode, eh Felix?]