2Lava LampA lava lamp consists of an enclosed container with two substances of different densities. One substance is wax and the other is a less dense oil.Using heat from a light-bulb in the bottom of the lamp, the oil and wax are heated up.
3Geologic CuriositiesCan you explain the motion of the wax in the lava lamp over time in terms of energy?In terms of the lava lamp, where is an Endothermic action? Exothermic action?
4Connection to Earth Science (Geology) Energy moves through the earthEither its transported or transferred
5Heat transferOccurs when thermal energy is transferred from a warmer object to a cooler object
6Types of heat transferRadiation Conduction Convection.
7RadiationThe transfer of energy through empty space or a gas medium is called radiation.No direct contact between a heat source and an object is required.
8ConductionHeat transfer by direct contact of particles of solid or liquid matter is called conduction.The energy moves but the medium does notAn example is when a spoon heats up in a hot pot of soup.
9ConvectionThe transfer of heat by the movement of a heated fluid (liquid or gas) is called convection.The medium moves to transport the heat from one place to another
10Does gas convect or radiate heat, energy? Generally air convects , because it moves to transfer the heatForms of energy like light and UV Radiate through air, because the energy does not create air currents
11The oil and wax movement in a lava lamp is an example of convection
12Convection Gain heat, Faster atoms, spread out Greater volume for same mass = less denseRise up, and lose heat to other objectsPushed to side by newer, hotter materialCools, loses heat, more dense, sinks
18Results of convectionHeat added to lithosphere may melt the rock, forming magma that flows from volcanoesThere is a current created in the Asthenosphere causing rotation in the mat .The crust and lithosphere also undergo pressure to move
19UpwellingRegion of Astenosphere that the hottest material moves to the top of the layer
20Convection CycleOne complete rotation of material that moves from heat source to top of layer and back to sourceFor water, cycle can take secondsFor the Earth, cycle can take millions of years
21Convection is the engine of the Earth Heat from deep inside the Earth rises through conduction to the top of the mantle.The material at the bottom of the Astenosphere begins to move upward as it becomes less dense this creates an area of upwelling
22Convection cycle continued 3. As the heated material rises to the top of the layer it transfers its heat to the lithosphere/crust and begins to cool, and becomes denser again4. The cooler material is pushed to the side by hotter material beneath5. The cooler material sinks towards the bottom of the layer over time6. Cycle repeated
23Final QuestionsName at least 3 examples of convection cycles that can happen on earth.How does heat effect density?
25Difference in motion Astenosphere bends and slides Crust/lithosphere breaks and is carried along
26Steps to convection in a pot As soup at the bottom of the pot gets hot, it expands and becomes less dense.The warm, less dense soup moves upward, floating over cooler, denser soup.At the surface, the warm soup spreads out and cools, becoming denser.Then gravity pulls this cooler, denser soup down to the bottom, where it is heated again and begins to rise.
27Heated lava lampWhen the lamp is turned on, both the wax and the oil absorb energy.This causes the individual molecules of both substances to spread farther apart.But the molecules of wax spread apart much more than the molecules of oil do
28Density and heatIn eighth grade, you learned that the density of a substance changes when it absorbs energy.As the molecules get more energy, they vibrate faster and farther, decreasing the density.We imagined the molecules to be connected by little springs. When the substance absorbs energy, the “springs” stretch a little farther, increasing the volume of the material.It has no effect on the mass of the material or the size of the individual molecules, only on the size of the sample.If the volume of the sample increases and the mass does not, the density will decrease.