Remember the old science class project making clocks operated by potatoes? You can do the same thing with mud–either from scratch, from a kit, or with a ready-made clock.

Essentially, the potatoes and the mud work like a battery. A nail and copper wire into the potato or mud activates electrons causing a chemical reaction that generates an electrical impulse to operate the clock.

Both the potato and the mud versions are pretty environmentally friendly and sustainable timepieces which save energy and conventional batteries by running on elements found in the earth, or in the case of mud, using the earth itself to create a reaction between it and the metals copper and zinc.

Mud clock from Malpin.

Kind of similar to how our biological clocks control our circadian rhythms, these clocks function with a biological metabolism of their own that operates via the chemical reaction. As long as you have a good mud supply of mud or potatoes, the clocks should produce enough electricity to operate indefinitely as long as their bodies hold out–which only time will tell.

Designer Variety
A more stylish “chronobiological” modelof the mud-operated clock, first exhibited in 2008 at Dutch Design Week, is Dutch designer Marieke Staps’s Soil Clock, shown above and at top, which displays the time on a nice wooden timepiece. In Staps’s design, the plants are merely decorative, a reminder that the clock needs watering now and then to keep time.

DIY Home Grown Clocks
The potato and mud clocks make a great home science activity to do with the kids. If you want to save time or give one as a gift, you can just go with a ready-made  mud or potato kit.

Mud Clock Kit, from $32 via Amazon.
Potato Clock Kit, from $18 via Amazon.

Go grow some time.

Soil Clock £35.50, plants not included.