Scissors only, with a grown-up in the room. If a step seems to want a knife, snip or fold instead.
What you need: card · scissors · straws · paper clips · poster putty · jar lids · coins · a pencil.
A weather vane on a church is pointing north. Is the wind blowing towards the north, or coming from the north?
Coming FROM the north. The arrow points into the wind. A north wind comes out of the north.
Why it matters: if cold weather comes on a north-east wind, a vane swinging to
north-east is a warning. Read backwards, it is a wrong one.
Two Centers
Making · Projects · Page 2 of 6
DIRECTIONS: Read this before you cut anything, or your vane will just spin.
A big tail alone does not work. A vane needs two centers in different places: the center of weight (the pivot goes there) and the center of area (where the wind pushes). In one flat piece of card they are the same place, so nothing turns.
So drag the balance point forwards: tape coins or putty onto the head until it
balances in front of the dot on page 3.
The Vane
Making · Projects · Page 3 of 6
DIRECTIONS: Glue onto card, cut two, glue them together. Copy the dot onto both sides.
The pivot goes in front of the dot (page 2).
The dot is the center of area, 74 per cent back from the tip. Add weight to the head until the vane balances about an inch in front of it.
The Pivot, and Pointing It North
Making · Projects · Page 4 of 6
DIRECTIONS: Build it indoors and test it with a puff of breath before it goes out.
Step
How
Why
Straighten a paper clip
One end straight and as long as you can make it. Leave a little hook at the bottom.
This is the spindle. It is thin, so there is almost nothing for the vane to rub against — and friction is the difference between a vane that answers a breeze and one that only moves in a gale.
Stand it in putty on a jar lid
A lump of poster putty or modeling clay in a jar lid, wire pushed in, standing straight up.
It has to be vertical. A leaning spindle makes the vane roll to the low side and sit there whatever the wind is doing.
Tape a straw across the vane at the balance mark
Straw upright, taped flat to the side of the card, its middle on the mark.
The straw is the bearing. Taping it anywhere but the balance mark puts the pivot in the wrong place and undoes page 2.
Drop the straw over the wire
It should spin with a puff of breath. If it does not, the wire is bent or the straw is squashed.
Test it indoors before it ever goes outside. Outdoors you cannot tell a stuck vane from a steady wind.
Point the lid’s north mark at TRUE north
Find north with a stick and two stones — the method is on sheet 11.
A vane that is a compass-error out reads the wrong direction all year, and nothing about it will look wrong.
Mark the eight directions round the lid: N, NE, E, SE, S, SW, W, NW.
The Wind Rose
Making · Projects · Page 5 of 6
DIRECTIONS: One box a day, same time, from the middle outwards along the way the vane pointed.
A bar chart bent into a circle. After a few weeks the longest arm is your
prevailing wind.
A Month Later
Making · Projects · Page 6 of 6
DIRECTIONS: Wind rose in front of you.
Which arm is longest? That is where your weather mostly comes from. Was it the one you would have guessed a month ago?
Is there a direction the wind almost never comes from? Go and look that way — is there a hill, a big building, or nothing at all?
Pick the three wettest days from your rain gauge log. Which way was the wind on each? Do wet days arrive from one particular direction?
Somebody says "the wind is going north today." What would you ask them to make sure you both mean the same thing?