A simple machine makes work easier. It distributes the force needed to do work over a longer distance. The most widely used simple machine used at our garden is a shovel. There are two parts to a shovel: the handle and the blade. We primarily use 3 different types of shovels.
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| Digging shovel, Kids digging shovel, Drain spade, Square pointed shovel |
Digging shovels have a curved scoop blade and are used for digging holes in soft soils and transplanting trees and shrubs.
Square point shovels are used for scraping, digging hard packed soils, and trenching.
Drain spades are very narrow with slightly curved sides. They are used for clearing trenches, transplanting small shrubs, and adding flowers to an established bed.
Shovels are Class 3 levers because the fulcrum is at one end, and the effort is applied between the fulcrum and the load. Other examples of class 3 levers are brooms, hoes, and baseball bats.
Class 2 levers have the fulcrum at one end of a lever arm and the load is between the fulcrum and the effort. Examples of class 2 levers are wheelbarrows, bottle openers, and doors.
Class 1 levers have the fulcrum located somewhere between the effort and the load. Examples of class 1 levers are claw hammers, pliers, and scissors.
A great mnemonic device to remember levers is fre123:
- Fulcrum in in the middle for Class 1 levers
- Resistance is in the middle Class 2 levers
- Effort is in the middle for Class 3 levers
Safety is important in a school garden. The safety rule that we use in our garden is that the blade should never be above the knee when carrying the shovel. Head injuries can occur when students lift the blade over their shoulders. Children have difficulty balancing the shovel because it is heavy at one end. Another reason why we apply this rule is that students will use the shovel as a baseball bat and swing it or as a sword and tap other shovels in the air, which could lead to injuries.
