- Philip Henriksson

# How many blades of grass are there? asks Valdemar 7

**How many blades of grass are there in the world? / Valdemar 7 years from Sweden**

Thanks, Valdemar, what an excellent but tricky question.

Grass exists all over the world, and there are about 12,000 types of different grass species. It’s not only cows, horses and other animals that eat grass; humans also love grass. The grass we eat and make different foods and drinks out of is not quite the same grass that’s on your lawn. Wheat, corn, rice, barley, and other cereals we eat every day are actually grass plants. With the seeds from this kind of grass, we make bread, spaghetti, popcorn, cakes and much more. Bamboo is also grass and something we use to build things.

*So, then how many blades of grass are there in the world then?* It’s impossible to answer, but can you come up with a way on how we could estimate it?

Perhaps this could be a way: It is much easier to count the number of blades of grass in a small area, right? Then we can look up how much of earth is covered in grass and with that we could calculate how many blades of grass there are on earth. What do you think, should we give it a try?

- Let’s say there are 10 blade of grass per square centimeter.

- That means we have 10 blades/cm2 x 100cm x 100cm =100,000 blades of grass per square meter

- And 100,000x1000x1000=100 billion (100,000,000,000) blades per square km

- Earth surface is 510 million square km and 29% of this is land (71% is water). 20-40% of the land is grassland according to the UN, so we’ll go with 30%. This means - 510,000,000x29%x30%= 44.37 million square km of grass

Total number of blades = 100 billion x 44.37 million = 4,437,000,000,000,000,000

**So in other words, there are 4.4 quintillion blades of grass in the world**

If you think it's hard to follow, draw it on a paper!

But this was just a fun estimation, so you better get out and start counting if you want to know for sure!

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