WEATHER

Convection Currents of Air

Safety Rules:

Parent supervision

Take care with fire or heat

Take care with scissors

Materials you need are:

a sheet of light cardboard

scissors

a piece of fine wire (about 50cm long)

sticky tape

a candle

matches

Cut the paper into a spiral as in the diagram. Attach the wire to the paper so that the paper spiral can turn freely and bend it as in the diagram. Place the candle under the wire and heat it. Watch the spiral.

The paper spiral should turn due to convection currents generated by the hot air.

Make a Wind Box

Safety Rules:

Parent supervision

Take care with fire or heat

Take care with a knife

 

Materials you need are:

a large glass fish tank

a large piece of thick cardboard

a short candle

matches

a knife to cut the 2 chimneys in the cardboard

Set up the materials as in the diagram. Cut two holes in the lid for chimneys that have diameters of about 2 cm. Place the candle under one of the chimneys. Make sure that the candle is short enough that it will not burn the lid. Light the candle, cover the fish-tank with the lid and allow the candle to burn for a few minutes. Quickly lift the lid slightly and extinguish the flame. Don't allow the smoke to escape. Watch the movement of the smoke.

Smoke will move out of the 'hot air' chimney (hot air rises) while cooler air from outside enters through the 'cool air' chimney (cool air is heavier than hot air)to replace the hot air. This creates a wind effect.

Make a Wind Vane

Safety Rules:

Parent supervision

Take care with scissors

 

Materials you need are:

a piece of thick cardboard

scissors

cotton thread

a sewing pin

sticky tape

paperclips

Cut out the arrow shape as in the diagram. Attach some paperclips to the front end of the arrow to weigh it down. Find the balance point by sticking a pin in until the arrow hangs horizontally and tie on the piece of cotton thread at this point. Hang it up where the wind blows and it point the wind direction. Try different long thin shapes.

Make an Anemometer (Wind Speed Indicator)

Safety Rules:

Parent supervision

Take care with a knife and a hammer

Take care with glue (It is poisonous)

 

Materials you need are:

a supporting pole

a headless nail

2 pieces of light wood (about 50cm X 2.5cm X 0.5cm)with a hole in the

middle of each

a pointed pen top

4 plastic drinking cups (one must be a different colour to the others)

some quick-drying glue

4 nuts and bolts

a hammer

a spanner

Use the diagram. Hammer the nail head first into the supporting pole. Push the pen top through the central hole in each wooden piece and glue the pieces at right angles to form a cross. Use nuts and bolts to fasten a cup to the end of each wooden piece.Push the pole into the ground so it stands upright. Rest the pen top on the nail. Use plasticine if your anemometer needs balancing. Wait for some wind and watch your anemometer revolve.

Fog in a Bottle

Safety rules:

Parent supervision

Take care with hot water

 

Materials you need are:

a large clear jar

hot water

a strainer (or plastic wrap)

ice cubes

Fill the bottle with hot water and cover it to warm it. Leave for 10 minutes. Pour out all except about 3 cm of water. Put a strainer over the opening. Place ice cubes in the strainer and watch.

The colder ice cubes should cause the original warm water vapour to condense into fog.