Completing the movie

Upon completion of our limestone movie, we have both enjoyed the expirience and the chance to have an opportunity to create our very own movie.

The movie is 8 minutes and 51 seconds in length. We have both tried to be as creative while presenting a current topic that is affecting our world today. 

Acid Rain

Carbon dioxide in the air can dissolve in rain water to form carbonic acid, H₂CO₃.

CO₂ + H₂O  H₂CO₃

Carbonic acid is a weak acid. It partially ionises to form hydrogen ions.

H₂CO₃  H⁺ + HCO₃^-

The hydrogen ions from carbonic acid give natural rain water a slightly acid pH value of 5.6. Over millions of years this very dilute acidic solution has been responsible for the formation of caves in areas of limestone rocks. Limestone is made of calcium carbonate, which reacts with acids.

calcium carbonate + acid  calcium salt + water + carbon dioxide

During the last century the rain water in some parts of the world has become far more acidic. This acid rain has been caused by the emission of pollutant gases such as sulfur dioxide. When coal is burned in electricity power stations, sulfur impurities form sulfur dioxide.

S + O₂ SO₂

The gas is also produced when fuels obtained from crude oil are burned. When sulfur dioxide is released into the air it reacts with water and oxygen to form sulfuric acid, H₂SO₄.

Sulfuric acid is a strong acid. It ionises completely to hydrogen ions.

H₂SO₄ 2H⁺ + SO₄^2-

This gives rain water a pH below 5.0. Rain water that has this higher level of acidity can cause damage to buildings and statues, particularly those made of limestone. It can also reduce the growth of, or even kill, trees and crops. Acid rain may even lower pH of water in lakes, killing fish.

When acid rain occurs, it can damage buildings and statues that have been in place for hundreds of years. 

Limestone

Limestone is mainly calcium carbonate, CaCO₃, which when heated breaks down to form calcium oxide and carbon dioxide. Calcium oxide reacts with water to produce calcium hydroxide. Limestone and its products have many uses, including being used to make cement, mortar and concrete.

Carbonates react with acids to produce carbon dioxide, a salt and water. For example:

calcium carbonate + hydrochloric acid → carbon dioxide + calcium chloride + water

CaCO₃ + 2HCl → CO₂ + CaCl₂ + H₂O

Since limestone is mostly calcium carbonate, it is damaged by acid rain. Sodium carbonate, magnesium carbonate, zinc carbonate and copper carbonate also react with acids: they fizz when in contact with acids, and the carbon dioxide released can be detected using limewater.

When limestone is heated strongly, the calcium carbonate it contains decomposes to form calcium oxide. This reacts with water to form calcium hydroxide, which is an alkali. Calcium hydroxide is used to neutralise excess acidity, for example, in lakes and soils affected by acid rain.

Start of the Movie

As we have began our movie, a lot of time is being spent on the art part behind the scenes to create every clip more creative.

We have however, realized the amount of work that needs to be put in and will dedicate the hours to complete the podcast on time.

Although there is a lot of work, enjoyment and excitement is also coming from creating the podcast. Excitement especially as it will be enjoyable to see what the full completed version of the movie will look like.

The Beginning of the Movie

Initially, myself and Ashleigh wanted to create what we had previously done with Mandy. However decided to stick to what we felt more comfortable with, with hopes that it would turn out as we wanted.

As we began we realized Movie Maker would be the best tool to use to enable us to create our podcast. We were more familiar with Movie Maker, and knew that we could help each other if one became stuck. This was always going to be the best option for us.

We have invested in a new pen drive so that when we are finished, that is what will be used to save the work on.

We do hope that it will work on other computers and will try it out before submitting it on Monday 12th of May

Sinkhole in Hemel Hempstead

The recent sinkholes in Hemel Hempstead left a lot of people shocked and surprised and the size of the hole, and how quickly it happened. 

The fact that it was occurring on people's driveways, alongside the motorways and nearly underneath people's houses was terrifying for some to understand.

The 15ft deep sinkhole closed the M2 motorway near Kent.

These sinkholes occur after heavy rainfall. Rainfall seeps through the soil absorbing carbon dioxide and reacts with decaying vegitation, creating a slightly acidic water. Water moves through spaces and cracks underground, slowly dissolving limestone and creating a network of cavities and voids. As limestone dissolves, the pores and cracks are enlarged and carry more acidic water. 

Sinkholes are therefore formed when land surface above collapses or sinks in to the cavities, or when surface materials is carried downward in to the voids. 

Weather

To look in to the cause of limestone and sinkholes, we have to look at our weather and why it could be the main cause of the problem.

Much of the worlds weather is determined by the movements of jet streams. Jet streams are the current of air that travels the globe at high altitude. British weather is usually determined by the streams blowing in across the Atlantic from Southern United States.

Does climate change also have a part to play?

Yes, anything that affects the amount of energy absorbed from the sun, or the amount being radiated by the Earth, that is the affect of climate change.
There are growing evidence that the warming is due to vastly increased- qualities of greenhouse gases in the atmosphere. Strongest, most important greenhouse gas is the water vapor.

What causes Sinkholes then? 

Sinkholes occur when there's a collapse caused in the surface area. Chemical dissolution of carbonate rocks or suffusion processes in sandstone. You have two types of sinkholes, artificial or natural.
Natural processes of erosion is a gradual removal of soluble bedrock by percolating water, which is the collapse of a cave roof.
Groundwater may dissolve the carbonate cement holding the sandstone particles together, which gradually forms a void.

Artificial processes are mines and salt cavern storage in salt dons. They can occur from over pumping and extracting of groundwater and subsurface fluids.