This week's science topic of caves was suggested by one of the students for us. Caves are formed when are usually made when water runs over soft rock, such as limestone. The acid in the water slowly eats away the limestone, making a hole. The hole gets larger and larger. If the water finds a new path, the cave is left dry.
As you can see in the photos there were a few caves beginning to form in the cups where the sugar was washed away by the 'rain'. However, as can happen sometimes in science experiments, it doesn't always work out exactly as planned!
As mentioned above if the water finds a new path out the cave is left dry. Unfortunately in our caves the holes made at the bottom weren't big enough and our caves were definitely underwater caves.
But we learnt the cave formation process and scientists learn both from observations and mistakes in their experiments. And we had a lot of fun with the messiness as well.
In preparation for learning how caves are formed we learnt about the types of rocks today.
Although there are many types of rocks on earth and we can name lots of them, we learnt that they can all categorised as three main types:
As we only have one lunch time to learn about something you could study for years we kept it very simple. And also used food to help us understand the types.
Igneous rocks are formed when magma (molten rock deep within the earth) cools and hardens.
Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of materials. Over many hundreds of thousands of years these layers of sediments form on top of each other.
We made our own sedimentary rocks out of layers of bread, rice bubbles, chocolate chips and coconut to represent the layers.
Metamorphic rocks are formed when the original rock changes (metamorphosis) from either intense heat or pressure. We chose to change our rocks with pressure and squashed our rocks down.
And of course we got to eat our rocks at the end!!!
Here is a video to help you learn more about rocks at home.
For our first experiment of the year we tested our hypothesising skills and observations skills.
First we observed what happened when we mixed two jars of red and blue cold water together.
We observed that they mixed quickly to become purple.
We then thought about what would happen if one of the jars was hot water. The photos show some of the things we observed: