Gallery 3

Sediment Tank

Photo of Sediment Tank exhibit

Over millions of years sediments build up in layers at the bottom of water bodies such as oceans, creating sedimentary rock.

How it works

Flip the tank to see the sediments slowlly fall, forming layers along the bottom of the tank.

Things to try or ask around the exhibit

  • What happens when you flip the tank?
  • Are the colours mixed together when they settle?
  • If this happened over a long time, which sediments would be the oldest?


Erosion from wind and water wears down rocks over millions of years. The dust and sand produced eventually washes into streams and rivers where it settles to the bottom or is washed out to sea.

Over time different types of sediments form layers one atop the other. As more and more sediment is laid down, the weight of all the new layers on top compress the ones underneath. Eventually after millions of years the layers are squashed so much they become a single dense hard rock called sedimentary rock.

You can still see the layers in these rocks and they can help us understand how old the rock is and the kind of environment it was in at the time. Fossils like dinosaurs are found in these layers, getting buried under more and more sediment.

Finding the science in your world

Sedimentary rocks give us an insight into the past environmental conditions of the Earth’s surface as each one is layed down by different weather and climatic events. Found in sedimentary layers are all the world’s fossils, preserved in the layers after having been buried by them over thousands or millions of years.

Sedimentary rocks are also used in building structures. Slate, sandstone and limestone are all sedimentary rocks.