Here’s how science can help you build the perfect sandcastle

Woo! Image: Getty.

Whether we prefer water sports or relaxing with a good book, the humble sandcastle is often a seaside must. But what’s the secret to building a majestic sandcastle that will withstand the tide of time? Luckily, there’s a scientific formula for that.

It all started back in 2004, when a holiday company asked us to investigate the question. As a sedimentologist, someone who studies fragments of rock, I began pondering what kind of beach would work best for castle building. To find out, I compared the sand from the ten most popular beaches in the UK at the time.

Though in truth any sandy beach will do, Torquay came out top with its delightful red sand, closely followed by Bridlington, with Bournemouth, Great Yarmouth and Tenby tied in third. At the bottom of the league was Rhyl.

Having selected a beach one has to find the perfect spot. Now this is a question of taste rather than hard rules. Some might prefer a spot close to the car park with easy access when the rain arrives, while others might want to stay next to a cafe. Others yet might hanker after the secluded fringes of the beach, perhaps sheltered by natural promontories of rock that keep the biting wind at bay.

Torquay harbour. Image: Averoxus/Wikimedia Commons.

Now a castle should be a symbol of military strength, but to stand proud one needs strong sand. The strength of sand depends on the properties of its individual grains and on the water between them. The more angular the grains, the better they will lock together. The more a grain is transported the more rounded it becomes. Microscopic shell fragments work well in this regard. The finer the grains the more they hold the water. And water matters.

Too much water and your sand will flow, too little and it will crumble. You need to get it just right and your castle will stand proud and last. It’s all down to the surface tension of water – the thing that gives the “meniscus”, or skin, to a glass of water and holds down that glass when placed on a wet bar top. The film of water between individual sand grains is what gives sand its strength, too much and it lubricates one grain over the other, but just right and it binds them strong.

The magic formula

Now the experimentation we did suggested that the perfect sandcastle requires one bucket of water to eight buckets of dry sand. Or if you want the magic formula: Water = 0.125 x Sand. So assuming that you don’t have any science gear with you, then you are looking for a spot close to the high tide line – usually marked by a line of seaweed and flotsam – and the low tide line where sand is still visibly wet and the waves are close. But remember that this will change as the tide comes and goes during the day.

High tide line. Image: author provided.

My next tip refers to quality of your tools. In my experience there is a direct correlation between the age of the builder, spade size and the speed at which boredom sets in. Adult helpers find the smallest spade nothing but frustrating, and while young assistants might aspire to use the biggest spade, it is often too big to handle. A selection of tools will keep the workforce in harmony.

The bucket also has to be the perfect size and shape. The best buckets are the simple round ones – not the ones with the fancy turrets which when turned out produce a castle in itself. A round bucket will allow you turn out countless towers and architectural features. A single bucket can be turned out several times to create a large mound from which you carve an amazing tower.

As you build, spare a thought to the story, not just of the castle one is building with its tales of derring-do, but also the story of the sand itself. Each grain is a fragment of rock and contains a story of relict mountains, ancient rivers, dinosaur-infested swamps and seas, of past climates and events which tell the amazing story of our planet. The red sand of Torquay once blew in giant sandstorms, as the area was once part of a desert far greater than that of the Sahara. The sand at Bridlington or Great Yarmouth tells a tale of giant ice sheets and drowned lands below the North Sea.

The ConversationMy next tip refers to size. Yes, size matters – at least in the game of sandcastles. The modest castle with perfect towers, battlements and moat is okay, but it is the huge castles which break the beach horizon that inspire awe and wonderment in people that pass by. Think big! Pebbles, shells, driftwood fragments and feathers all enhance a castle. And let’s face it: a castle is about being seen. And although there may be science behind the humble sandcastle, don’t forget to have fun building it.

Matthew Robert Bennett is professor of environmental and geographical sciences at Bournemouth University.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

To transform Australia’s cities, it should scrap its car parks

A Sydney car park from above. Image: Getty.

Parking may seem like a “pedestrian” topic (pun intended). However, parking is of increasing importance in metropolitan areas worldwide. On average, motor vehicles are parked 95 per cent of the time. Yet most transport analysis focuses on vehicles when they are moving.

Substantial amounts of land and buildings are set aside to accommodate “immobile” vehicles. In Australia, Brisbane provides 25,633 parking spaces in the CBD, Sydney 28,939 and Melbourne 41,687. In high-demand areas, car parks can cost far more than the vehicle itself.

However, parking is not just an Australian problem. By some estimates, 30,000 square kilometres of land is devoted to parking in Europe and 27,000 km² in the US. This parking takes up a large part of city space, much of it highly valued, centrally located land.

Traditionally, transport planners believed that generous parking allocations provided substantial benefits to users. In reality, excessive parking is known to adversely affect both transport and land use. These impacts, along with recent land-use, socioeconomic and technological trends, are prompting cities to start asking some important questions about parking.

Australian planners must engage with emerging trends to help cities work out the best way to reclaim and repurpose parking space in ways that enhance efficiency and liveability while minimising disruption.

Here we chart likely challenges and opportunities created by these trends over coming decades.

Key trends affecting parking space in cities. Image: author provided.

Land use

All Australian cities have policies to encourage densification, consolidation and infill development in their centres. In conjunction, some cities are setting maximum limits on parking to prevent it taking over valuable inner-city properties.

Transit-oriented development (TOD) has also become popular, at least on paper. This is another form of urban consolidation around transit nodes and corridors. It is known to benefit from high-quality urban design, “walkability”, “cyclability” and a mix of functions.

These developments mean that people who live in CBDs, inner-ring suburbs and near public transport stops will use cars less. Consequently, demand for parking will decrease.

Some non-TOD suburbs are trying to replicate inner-city features as well. For example, some suburban shopping centres have introduced paid parking. This is a significant shift from previous eras, when malls guaranteed ample free parking.

Suburbanites who lack easy public transport access will continue to rely on cars. But rather than driving all the way to a CBD, commuters will increasingly opt for park-and-ride at suburban stations, thereby increasing demand for park-and-ride lots at public transport interchanges. However, excessive capacity might hurt rather than help patronage.


Social trends

In addition to land use, several social trends will affect the need for parking.

First, young people are delaying getting drivers’ licences because driving is culturally less important to them than in previous generations.

Second, people of all ages are moving from outer suburbs to inner cities. For many, this means less driving because walking, cycling and public transport are more convenient in inner cities.

 

inally, the emergence of Uber, Lyft and vehicle-sharing arrangements means that people are not buying cars. Research suggests that each car-sharing vehicle removes nine to 13 individually owned vehicles from the road.

Together, these trends point to a reduced need for parking because there will be fewer cars overall.

Technology

The importance of technology in parking is rising – paving the way for “smarter” parking.

The emergence of a host of smartphone apps, such as ParkMe, Kerb, ParkHound and ParkWhiz, has begun to reshape the parking landscape. For the first time, users can identify and reserve parking according to price and location before starting their journeys.

Apps also make available a host of car parks that previously went unused – such as spaces in a residential driveway. This is because there was no mechanism for letting people know these were available.

In addition, smart pricing programs, such as SFPark in San Francisco, periodically adjust meter and garage pricing to match demand. This encourages drivers to park in underused areas and garages and reduces demand in overused areas.

The advent of autonomous vehicles promises to have dramatic impacts on transport and land use, including parking.

According to one school of thought, mobility services will own most autonomous vehicles, rather than individuals, due to insurance and liability issues. If this happens, far fewer vehicles and parking spaces will be needed as most will be “in motion” rather than parked most of the time.

More space for people and places

The Tikku (Finnish for ‘stick’), by architect Marco Casagrande, is a house with a footprint of just 2.5x5m, the size of a car parking space. Image: Casagrande Laboratory.

The next decade promises much change as emerging land-use, socioeconomic and technological trends reshape the need for, and use of, parking. Cities will devote less space to parking and more space to people and places.

Parking lanes will likely be repurposed as cycling lanes, shared streets, parklets, community gardens and even housing. Concrete parking lots, and faceless garages will likely be converted to much-needed residential, commercial and light industrial use.

The ConversationBy transforming parking, much urban land can turn from wasteland into vibrant activity space.

Dorina Pojani, Lecturer in Urban Planning, The University of Queensland; Iderlina Mateo-Babiano, Senior Lecturer in Urban Planning, University of Melbourne; Jonathan Corcoran, Professor, School of Earth and Environmental Sciences, The University of Queensland, and Neil Sipe, Professor of Urban and Regional Planning, The University of Queensland

This article was originally published on The Conversation. Read the original article.