After showing Tabitha the number rods recently, I decided to make a set of red rods which are a sensorial material designed to teach visual discrimination of length. Most of the credit for these goes to my wonderful dad. I phoned him up to ask if he could give me a lift to a DIY shop at some point. He asked what I wanted to make and so I explained. Next time I saw him, he handed me ten pieces of wood all cut to size!
To make ten full-size rods (shortest rod 10 cm, longest rod 100 cm) requires 5.5 m of wood. I’m not sure where my dad got the wood from, but you can buy 3 x 2.1 m from B&Q for £10.95 and probably less if you found somewhere that would sell you the exact length needed. Add on the cost of spray paint (Plasti-kote Gloss Super at £7.98) and you have a set of red rods for £18.93, instead of £40+.
As you can see, Aaron got hold of them while I was at college and decided to turn them into rulers!
First I used an orbital sander to smooth the sides and round the edges (sandpaper would also work fine). Then I applied two coats of spray paint over a couple of days. The paint dries very quickly but the elements conspired against me and the rods were rained and even snowed on! They’re not perfect, they do have the odd knot hole or blemish, but they look pretty good and feel nice to handle. We do need some larger work mats though!
They are slightly chunkier than standard Montessori red rods, with a diameter of 1.25 inches instead of 1 inch. This seems to be working well for us, as the rods are temporarily being kept in the front room until I clear a space for them on the shelves upstairs, and they haven’t yet been used as weapons!
Montessori Primary Guide has a description of how to present the red rods, and there are also some helpful videos on Youtube. Here Tabitha is making sure all the rods are aligned on the left (sorry for the poor quality photos, we had bright sunlight streaming in through the window which I can’t really complain about!).
As you can see, she is making some mistakes but an important principle of Montessori materials is that they are self-correcting.
It’s time to check her work with the shortest rod and she soon realises that there is a problem.
Ah, that’s better!
The 1 m rod has also been used to measure out the lengths of several different dinosaurs (a triceratops would just about fit inside our house) and my lovely friend Ali had the great idea of laying out 100 unit cubes next to it to illustrate the relationship between centimetres and metres.
It would be easy to make a similar set of number rods, by using masking tape to cover sections of the wood and painting with red and blue. The gloss spray paint gives a much more professional finish than the acrylic paint I used to make our number rods a couple of years ago.
