Journal 3 – Colliding plates

When doing this practical we were trying to relate it to how tectonic plates work. After the practical we found out that the paper and the tectonic plates work very similarly. Geologists believe that tectonic plates move from gravity. Since the plates are denser the under layer of the earth, they sink. The weight causes them to slide down and go by the lower subduction zones. When the plates push against each other it causes plate movements. The plates don’t move quickly, in fact they move as fast as your fingernails grows. The average is around two inches a year.

Journal 2 – Plates that seperate

After working on this practical my group and I have understood the way in which this activity relates to mid-ocean ridges. The comcept that i have understood is that mid-ocean ridges is the area where most activity occurs within the ocean sea bed. It also produces rock through lava (which comes from the convection currents). Though what I have learnt about the plates is that when they seperate they rise up and then lengthen down, this then pushes the lava further away or close to the ridge to then cause the rocks to be younger or older. I noticed that with the paper emerging, it rose up to a certain point and then extended as we pushed up.

Journal 1 – Convection Currents

1. Explain what causes convection currents.

Convection is the flow of heat through a bulk, macroscopic movement of matter from a hot region to a cool region, as opposed to the microscopic transfer of heat between atoms involved with conduction. Suppose we consider heating up a local region of air. As this air heats, the molecules spread out, causing this region to become less dense than the surrounding, unheated air. For reasons discussed in the previous section, being less dense than the surrounding cooler air, the hot air will subsequently rise due to buoyant forces – this movement of hot air into a cooler region is then said to transfer heat by convection.

Heating a pot of water on a stove is a good example of the transfer of heat by convection. When the stove is first turned on heat is transferred first by conduction between the element through the bottom of the pot to the water. However, eventually the water starts bubbling – these bubbles are actually local regions of hot water rising to the surface, thereby transferring heat from the hot water at the bottom to the cooler water at the top by convection. At the same time, the cooler, more dense water at the top will sink to the bottom, where it is subsequently heated.

2. Use the diagram to clarify what a ’hot’ current does.

In the diagram the hot current referring to the crystal potassium permanganate is actually pushing the hydrogen in the water to the top of the beaker as the heat generated the gas is automatically pushed to the top.