1. Activity 46: Convection Currents  Challenge: How do differences in temperature cause a convection current?  Key Vocabulary:  Convection Current – the circulation of a fluid due to differences in temperature Read the Introduction on Page D-45

2.  Today we are going to mix cold and warm water in two different trials in order to observe the formation of a convection current.

3. PROCEDURE:  Follow the procedure om page D-46.  Complete the following data Table: Trial #SketchObservations Trial 1 Trial 2

4. Trial #SketchObservations Trial 1 Warm water flows out of holes and rises above the cold water Trial 2 Nothing happens. The cold water is already below the warm water.

5. Discussion:  How did the differences in temperature cause convection currents?  Convection currents require a source of HEAT  Since the core is much hotter than the mantle, it continues to heat magma in the mantle as it begins to cool and sink  In your notebooks, please answer questions 1-4

6. Analysis Questions: 1.a. Only trial 1 resulted in movement of water – the warm water rose upward and outward b. It is necessary for warm water to be at the bottom and cooler water to be sitting above it to form a convection current.

7. 2.When warm water anc cold water are mixed: a. The warm water rises to the top b. The cold water sinks to the bottom 3.If warm magma is lying beneath an area of cooler magma deep in the mantle, the hotter magma would rise and the cooler magma would sink. This would result in a convection current.

8. 4.Scientists believe that convection currents within the earth’s mantle caused by differences in temperature between the magma and mantle cause the plates to move.