drop (someone) a line
to write or mail a note or letter to someone
My friend promised that she will drop me a line when she gets to Singapore.
Science Experiments Ideas
Electricity Potato battery
Stick finger length pieces of copper and zinc wire one at a time into a raw potato. If you hold an earphone on the wires, you will hear distinct crackling.produce an electric current in the same way as a torch battery,but only a very weak one. The sap of the potato reacts with the metals in a chemical process and also produces electrical energy. We speak of a galvanic cell because the Italian doctor Galvani first observed this process in a similar experiment in 1789.