The following weather instruments are meant to be used to teach concepts. Because you will be making them yourself, they will not be incredibly accurate. To get the main ideas across, they don't need to be accurate, as a simple "Low," "Medium," or "High" is enough to get across the relation of air pressure, for example, to the possibility of rainfall.

Compress the tube or hand grip and seal both ends with the wooden plugs and the cement.
Tie the weight to one end of the grip, and hang the grip on the wooden stand by the other end.
Attach the pointer to the rubber tube so that is lies parallel with the floor.
Stand the notecard on the stand.
Mark where the pointer contacts with the card. As the air pressure changes, the tube will expand or contract. Mark these changes on the card.

Barometer Design #2:
    This barometer consists of a small sealed plastic box, bottle, or rubber ball. A spring clip is placed around the sealed container. As air pressure increases, it causes the spring clip to compress the container. As air pressure decreases, the greater pressure inside the container pushes outwards and expands the clip.
Materials:
        A sealed soft plastic box, bottle, or hollow rubber ball
        A spring clip
        A board to mount the system on
        A small stick to act as a pointer
        A notecard or a piece of cardboard
        Nails
        Glue

Place two nails into the board. These will be used to mount the barometer to the board.
Make sure the container is closed and sealed. A little wax or rubber cement can insure the seal. Place the spring clip around the container.
Mount the spring clip to the board by attaching one of its arms to the nails.
Attach the pointer to the other arm.
Place the notecard under the pointer, and mark where the pointer lies. As the pointer changes position, mark the new position on the card.
 
 

Beaufort Scale:
One of the easiest measures of windspeed is scale by Sir Francis Beaufort in1805. Beaufort orbserved, measured, and classified windspeeds and by the effect of the wind on the environment.

Beaufort  Number	Description	Windspeed (MPH)	Observations
0	Calm	< 1	Smoke rises vertically
1	Light Air	1-3	Wind affect smoke but not wind vanes
2	Light Breeze	4-7	Wind vanes move, leaves rustle, and wind can be felt on the face
3	Gentle Breeze	8-12	Leaves and twigs move and light flags wave
4	Moderate Breeze	13-18	Dust and paper move; small branches move
5	Fresh Breeze	19-24	Small trees sway; ripples can be seen in bodies of water
6	Strong Breeze	25-31	Large branches move; use of umbrellas becomes difficult
7	Moderate Gale	32-38	Whole trees move; people find walking against the wind mildly difficult
8	Fresh Gale	39-46	Twigs break off of trees; it is difficult to walk against the wind
9	Strong Gale	47-54	Buildings receive slight structural damage; branches break
10	Whole Gale	55-63	Buildings receive considerable structural damage; trees are uprooted
11	Storm	64-72	Widespread damage
12	Hurricane	72+	Extreme damage

Materials:
        1 stick about 1/2 meter long
        Cardboard, thin lightweight plastic, or thin wood
        Wire
        Metal washers
        A large nail
        1 long thick pole.
        glue
 

Drill a hole in the center of the stick.
Now drill a smaller hole one end of the stick, perpendicular to the central hole.
Cut thin notches in both ends of the stick. The notches should be no longer than 1 inch (2.5 cm) long, and sould be parallel to the central hole.

Cut the cardboard into:
A semi-circle shape
A trapezoidal fish tail shape
about the same size as
the semi-circle
A smaller rectangle
Place the semi-circle in the notch with the drilled hole. Place the trapezoid in the other notch. Secure the cards in place with glue.

Re-drill the hole in the end so that is passes through the card as well.
Run the wire through the hole in the end and allow enough to hang down so that the ends extend past the semi-circle.
Attach the rectangle to the wire.

Place the nail through the hole in the vain, through the washers, and into the end of the long pole.
You can calibrate this ananometer by marking the semicircle and correlating the marks to the Beaufort scale.

A rain gauge consists of a uniform container, a stand and a funnel to catch the rain. The most difficult part about making a rain guage is marking is precisely to so you can later measure the amount of the rainfall.
To calculate how the marks on the container need to be spaced, you need to know the diameter of the mouth of the funnel (X), and the inner diameter of the container (Y).

    The ratio of collected rainfall to actual rainfall is equal to the square of the ratio of the funnel's diameter to the container's diameter. If the funnel has a 2 cm diameter, and the container has a 1 cm diameter, then:

    A wet-bulb hygrometer is a device that measures the relative humidity using the difference in temperature created as one of two thermometers is cooled by evaporating water.
Materials:
        1 water-proof box (milk carton or drink box)
        2 thermometers
        a shoelace or other wick-like tubing
        glue

Attach the thermometers onto the sides of the box.
Cut a small hole into the box just under one of the thermometers.
Slip one end of the wick/shoelace around the thermometer, and let the rest of its length lie in the box though the hole.
Fill the bottom of the box with water, and make sure the wick/shoelace is resting in the water.
Place the system in a well ventillated area.