GIZMOS STUDENT EXPLORATION: CONVECTION CELLS -UPDATED STUDY GUIDE

GIZMOS STUDENT EXPLORATION: CONVECTION CELLS -UPDATED STUDY GUIDE Vocabulary: convection, convection cell, density, global conveyor belt, mantle, mid-ocean ridge, subduction zone, vector, viscosity Prior Knowledge Questions (Do these BEFORE using the Gizmo.) You place a pot of soup on the stove. As the soup warms you notice some areas where soup is rising up and other areas where soup is sinking down. 1. Why do you think some of the soup is rising up? It has the highest temperature. 2. Why do you think some of the soup is sinking down? The effects of boiling. Gizmo Warm-up When fluids (gases or liquids) are heated, they tend to move. This motion is called convection. In the Convection Cells Gizmo, you will observe and experiment with convection both in a laboratory setting and in several real-world examples. To begin, note the laboratory setup on the MODEL tab. A beaker of liquid is placed above a gas burner. Click Play ( ). The burner is now heating the fluid. 1. What do you notice? It is moving in a circle. 2. Drag the eyedropper into the beaker just above the burner and let go to release a drop of orange liquid into the beaker. What do you notice about the path of the drop? It floats up and down in a circular motion. Question: What causes convection cells to form? 1. Hypothesize: Click Play, add a drop, and watch the motion of the liquid. Why do you think convection tends to occur in heated fluids? It moves at a faster pace. Convention occurs in heated liquids because of the difference in temperature. 2. Observe: Click Clear drop. Under Show, select Temperature. The temperature scale runs from red (hot) to dark blue (colder). A. Where is the hottest liquid located? Bottom B. Where is the coldest liquid located? Top right corner C. Add a drop. Does the hottest liquid tend to rise or sink? Rise D. Does the coldest liquid tend to rise or sink? Sink 3. Observe: Click Clear drop, and then add a new drop to the liquid. Turn on Show micro view of drop. This view shows 21 molecules in the drop. Pay attention to how fast the molecules move and how much space they occupy as the drop moves around the beaker. (Note: If the drop gets stuck, add a new drop to the beaker.) A. In which part of the beaker do the liquid molecules move fastest? Closest to burner B. In which part are the liquid molecules most spread out? Hottest part 4. Explore: Click Clear drop and drag the probe ( ) into the beaker. Density is defined as the mass per unit volume. It is a measure of how tightly the particles of a substance are packed. Move the probe to different parts of the beaker, observing the temperature and density. A. What relationship do you observe between the temperature and density? The liquid that are less dense will float. B. Why do you think this is so? The temperature affects the size of molecules. It expands with heat and shrinks with cold. (Activity A continued on next page) CONTINUED..........................DOWNLOAD FOR BEST REVISION AND BEST SCORES