Understanding Wind Strength and Direction

Wind

• Wind can be a nuisance but it can also be helpful

Measuring Wind Strength

• An anemometer measures wind strength
• This helps determine if the wind is safe or dangerous
• Wind pushes a card upwards
• The stronger the wind, the higher the card rises

Wind Force Scale

• Calm: Smoke goes straight up
• Light Breeze: You feel the wind on your face
• Moderate Breeze: Paper blows about and small branches sway
• Windy: Large branches sway
• Strong Wind: Twigs break off branches, it is hard to walk against the wind
• Gale: Damage to buildings and trees occurs, uprooting them

Wind Direction

• Wind direction is the direction it blows from
• Sally's class used an oak tree and falling leaves to determine wind direction
• A compass divided the area around the tree
• Leaves were counted and cleared each day to record the wind's direction
• Weather vanes can be used to tell wind direction throughout the year
• Sally used a homemade weather vane and recorded the wind direction over two weeks
• She kept a 28-day record of wind and rain patterns, coloring boxes red for wind only and green for wind and rain

The Wind: Friend or Foe?

• Wind is invisible but its effects can be felt and observed
• It is air that is on the move
• Wind benefits: brings rain for crops, carries seeds and birds, and dries washing
• Wind is a foe when it drives sand into eyes, demolishes houses, makes families homeless, and can be deadly
• When a hurricane is approaching people should take cover and prepare to live for up to 3 days until rescue services arrive

Windmills and Aerogenerators

• Windmills have been used for centuries to grind corn and pump water
• They have been replaced by engines using other energy sources in Britain
• One problem with these is that the fuel cannot be replaced and it is also expensive
• Aerogenerators are modern windmills that generate electricity as the wind turns the blades
• Historically sailing ships depended on wind

Microclimates

• A microclimate is when a place has a different climate from the surrounding area
• Microclimates can be created using screens
• Dark surfaces like tarmac get hotter than light-colored surfaces like grass
• Brick and concrete take a long time to warm up from the sun but lose their heat slowly during the night
• Tall buildings can force the wind to swerve, sometimes funneling it between buildings and making it stronger

Wind Erosion

• Reddish dust on cars is sand carried by the wind
• Wind itself does no damage unless it is blowing really hard
• It is what the wind carries that does the damage
• When wind blows sand, the effect is like rubbing with sandpaper, which is called erosion
• The Sphinx is eroded partly by sand transported by the wind

The World's Rainforests

• One third of the world's land is covered in forest
• Rainforests are being destroyed to meet the worldwide demand for hardwood products
• Rainforest clear-cutting is done for furnishings, chopsticks in Japan (which are thrown away after each meal), tissues (rainforest is cleared and eucalyptus planted), Plywood (Most wood from Indonesia is made into plywood)
• Copper, gold and other minerals are mined in Indonesia, which leads to destroying forest to extract the metals and roads
• Some of the copper and wood is exported to Japan
• The island of Java and Bali are densely populated

Forest Destruction

• The Indonesian Government is moving people to other islands
• There forests are destroyed to provide farmland for some settlers and to work in logging camps for others
• Native peoples live in the rainforest without harming it
• To reach the best wood, bulldozers destroy other trees, plants and seeds
• Once the forest is removed the soil loses its fertility and is easily washed away
• Some animals can only survive in the rainforest
• If rainforests continue to be destroyed it affects everyone

Fighting Back

• Many forest peoples have decided that the only way to survive is to against governments and big companies destroying their homes

Rocks

• Igneous, sedimentary, and metamorphic rocks are rocks that are formed

Igneous rocks

• Basalt looks like rope, was runny when hot, has little holes where gas escaped
• Tuff looks like millions of small specks of dust and tiny bits of rocks stuck together
• Granite has big crystals

Sedimentary rocks

• Sandstone has sand grains in the layers, feel rough
• Shale is often grey in color, mud grains feel smooth to the touch
• If you put vinegar (a weak acid) in limestone, it will react

Metamorphic rocks

• Slate is a smooth rock
• Slate is one that has been squashed as a layer and breaks into thin sheets
• Mica schist glitters and the rock looks wavy

Fossils

• People who collect rocks and fossils are called rockhounds
• A fossil is the remains or trace of an animal or plant in a rock

Volcanoes

• There are two main types of volcano: shield and conical
• Shield volcanoes slopes are gentle and have runny lava
• A cross section of a conical volcano is made of lava and ash
• Lava in conical volcanoes is sticky and is pushed out of the vent
• Sometimes the vent gets blocked up and explodes to blow the top off or make a new side vent
• Ash and gas are blasted over a wide area and lava can destroy crops and villages

Explore how wind strength is measured using an anemometer and its impact. Learn about the wind force scale, from calm to gale, and how wind direction can be determined using trees, leaves, and weather vanes.