Visualising the green economy

I was thinking the other day as I drove to the shops to pick up screws for a building project that the amount of energy used just to pick up shopping is gigantic. I was wondering how much forest had become fossilized just for me to get that litre of diesel that I used to … Continue reading

Now that there are one billion cars on the planet

With one billion cars on the planet it might be prudent to consider our oil use. Most cars run on the stuff. GIVEN that there are today one billion cars on the earth.  the average car travels 15,000km a year and uses 1 liter to travel 12km.  Global oil reserves were calculated to be 1,383 … Continue reading

Children can learn complex mathematics on their own new study suggests

A recent news article on Kurzweil  suggests that  schoolchildren can independently develop strategies for solving complex mathematical tasks, with weaker students proving just as capable as their stronger classmates.

The horse and oat cart challenge

I maintain that this little problem will illustrate how the maximum size of a city is well below that experts currently state. In fact, this problem shows that without fossil fuel the sizes of cities will be severely restricted. This little problem sets a benchmark for how large a city can be, as it is … Continue reading

The horse and oat carts problem

Although horses eat grass, they need oats. Imagine then a horse carrying food from the area of production to the city where the oats will be consumed. The driver feeds the horse the oats from the cart. Is there a way the answer to this problem could illustrate for us the maximum size of a … Continue reading

City density

An average city in Europe may show a population density of about 5000 inhabitants per km2. City centres have much more, from 12,000 upwards. However, around 40% of the area of these cities is allocated to car transport system – for example, roads, garages, parking spaces, car showrooms, repair shops and so on. If the … Continue reading

Holding hands around the world

This problem was given to me during the Future Perfect festival I thought I would post it… If we who live on Earth stand and hold hands with each other, would we be able to form a circle around the Earth? Given that the average comfortable reach is about 1,2 meters hand to hand. Given … Continue reading

If all the world lived in one city… how big would it be?

Given the population of Earth is 7 billion And that the density of cities ranges from Mumbai – nearly 30,000 per square km Through Sao Paolo at 9,000 Through London at 5,000  to Copenhagen at 1,800 How much space would be needed for these different variants? For inspiration see the website PER MILE. For the … Continue reading

The land use of cities

Given a large city of one million. Given that the agricultural land needed to feed a family of four is about one hectare. Given that only about 30 % of land can be farmed. Given that the population density of cities can be around 5000 inhabitants per square kilometre. Calculate: If the city is circle-shaped, … Continue reading

Climate impact of cars

GIVEN: The average car in Europe weighs 1.5 metric tons (1500kg)and in the US: 2 tons (2000kg). GIVEN: One litre of petrol weighs 0.737 kg and one litre of petrol gives rise to 2.32kg of carbon dioxide. GIVEN: The European Fuel Efficiency Regulations demand maximum  5 litres per 100km. Calculate: How far must you drive … Continue reading