Force and Fan Carts Gizmo Answer Key

Name: Bernard Nash Date: 04-03-2022 Student Exploration: Force and Fan Carts Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: force, friction, position, speed Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. If you are pushing a shopping cart and you start pushing harder, what happens? The shopping cart gets faster 2. What happens to a shopping cart if you get it rolling and then release it? Until it is at rest, it rolls. Gizmo Warm-up 1. In the Gizmo, turn the fan Off. Click Play ( ). Did the cart move? Not at all 2. Click Reset ( ). Press the Low fan speed button to turn on the fan. Click Play. What happened? It rolled to the finish line 3. A force is something that causes change in motion. What provided the force that made the cart speed up? The fan 4. The speedometer shows the cart’s speed, or how fast it moves. A speed of 30 cm per second means the cart moves 30 cm every second. What was the final speed of the cart? 15 cms 5. Friction is a force that works against motion as surfaces rub each other. Click Reset. Select the No Friction surface. Click Play. What was the final speed this time? 18 cms Get the Gizmo ready: Activity A: Force and motion ● ● ● ● Click Reset. Change the Surface to Wood. Be sure there are no objects on the cart. The Fan speed should be set to Low. Question: How does force affect motion? 1. Run Gizmo: Press Play. What was the final speed of the cart? 8.2 cms 2. Predict: Would the cart’s final speed be higher or lower if the fan were set to Medium instead of Low? The pace of the carts would increase. 3. Experiment: Click Reset. Change Fan speed to Medium. Click Play. What was the cart’s final speed? 14 cms 4. Draw conclusion: Did the cart speed up more quickly with the fan on Low or Medium? The cart speeds up more on medium than low 5. Generalize: On Medium the fan provides more force than on Low. Make two rules by filling in the blanks below. (Put the same word in both blanks.) Force causes the If more force is used, the speed of the cart to change. speed of the cart changes more quickly. 6. Predict: Select the DATA tab. Choose Bar graph or Line graph. This graph shows the cart speed over time. How would the graph be different if the fan were on High? Why? Because the speed is faster with the fan on high, there will be a steeper inclination. 7. Test: Check your prediction with the Gizmo. What do you observe? The gradient is steeper because the fan moved more quickly when it was on high. 8. Extend: Design an experiment to test the effect of force on a loaded cart. You can choose any surface and any object to load onto the cart. In the space below, report your question, prediction, procedure, observations, and conclusion. ~How will the graph change if a soda bottle is placed on the cart at the same speed ~Once the item is loaded into the cart, my theory is that the cart will slow down, resulting in a lesser inclination. ~The procedure is to set the fan to medium and put the soda bottle on the cart ~I've noticed that the cart moves extremely slowly ~The conclusion is the more you put on the cart, the longer it will take to reach the finish line Activity B: Running out of steam? Get the Gizmo ready: ● Click Reset. Question: Why do objects slow down when there is nothing pushing them? 1. Observe: Use the Gizmo to explore the question above. Try different objects and surfaces. Each time, turn the fan Off while the cart is moving. (You may find it helpful to pause the Gizmo with the Pause ( ) button, turn the fan off, and then click Play to restart.) 2. Form hypothesis: What causes an object to slow down after no longer being pushed? The cart will slow down once the fan shuts off. ✏️ 3. Predict: Set Fan speed to High. Based on your hypothesis, circle all surfaces that will cause a moving cart to slow down after the fan is turned off. (You may circle more than one.) 4. Test: Run the trials using the Gizmo. Which surface(s) caused the cart to slow down? 5. Draw conclusion: What causes objects to slow down when they are no longer pushed? The surfaces caused the cart to slow down 6. Think about it: Imagine the track in the Gizmo went on forever. If there were no friction, how long would it take the cart to stop after you turned off the fan? Explain. It would continue moving at a constant speed without stopping. 7. Analyze: Which surface in the Gizmo has the most friction? Explain how you can tell. As the cart takes the longest to go across wood, it has the highest friction. Get the Gizmo ready: Activity C: Patterns in motion ● ● ● ● Click Reset. Select No friction. Place only the soda and book on the cart. Set the Fan speed to High. Select No Friction. Question: Are there any patterns in the motion of objects? 1. Run Gizmo: Be sure No friction is selected. Click Play. After about 3 seconds, turn the fan Off. (We recommend that you click Pause, turn the fan off, and then click Play to restart the Gizmo.) 2. Observe: Select the DATA tab. Select Position. The position of the cart is its location (how far from the start line). What pattern do you see in the position data after the fan is off? This graph is direct. 3. Connect: How is the final speed of the cart related to the pattern in the position data? The graph is a linear line because the end speed is the constant speed. 4. Analyze: Why does that pattern happen? (Hint: Think about what “cm per second” means.) The slope stays the same. 5. Observe: Select Speed. What pattern do you see in the speed data, after the fan is off? The graph increases until it hits three seconds, and then once the fan is turned off, the speed remains around 30 cm/s. 6. Connect: How does the bar graph (or line graph) show the pattern you found? It displays how quickly the trolley is moving relative to time. 7. Generalize: Fill in the blank below to state a rule based on what you saw. If there is no force, the speed does not change at all.