SCIENCE 1 ASSOCIATE DEGREE IN EDUCATION Lecture # 23 Mass and Acceleration

Relationship of Mass and Acceleration Investigate the relationship between mass and acceleration of an object. To begin this investigation, ask Students whether they think there is a difference between two trucks rolling down a hill. One is empty, and the other is fully loaded with heavy cargo. Let them speculate first (make sure they back up their hypothesis with science reasoning as much as possible, and accept different hypotheses). Then give them 15 minutes to experiment with their model trucks and different loads (for instance, use coins as a load). At the end of the investigation, each group should formulate its conclusion about what the relationship is among the mass of an object, how far it travels, and its acceleration.

Relationship of Mass and Acceleration Try this experiment yourself first. If you have difficulty timing the trucks to record their acceleration, consider switching the cars for balls on ramps or in tubes. A heavy and a light truck/ball that have similar surfaces and are rolled down the same ramp will roll the same distance. How far they roll depends on the speed of the balls at the bottom of the ramp, not the weight! Although a heavier truck/ball has more momentum than a lighter one, the surface’s push is greater on the heavy truck/ball. This surface push causes it to slow down at the same rate as the lighter ball.

Relationship of Mass and Acceleration It is difficult for Students to understand that objects fall at the same speed vertically. (Try dropping an empty and a full water bottle out a second-floor window at the same time. Both will hit the ground at the same time.) As with the bottles, the size or weight of the trucks (balls) does not affect how fast they reach the bottom of the ramps or how much farther they roll after they have left the ramp. However, the acceleration is different because acceleration depends on mass. Thus, heavier objects accelerate (positive and negative) slower than lighter objects.

Relationship of Mass and Acceleration These concepts are hard for Student Teachers to understand, and many hold misconceptions. You might need an additional session to make sure they have ample time to explore these concepts hands-on. They should see with their own eyes how a heavier truck or ball compares to a lighter one going down a ramp. You may also want to use longer ramps to see the phenomena more clearly. Use the time to develop a good conceptual understanding rather than introducing additional formulas, such as F = ma.

Teaching force and motion in elementary grades This week, you should prepare Students for their teaching of science in elementary school. It is essential to support them in making the transfer from their own study of science to becoming a teacher of science in the elementary grades. Many teaching strategies and pedagogies learned in this course are transferable to teaching at elementary grades. But the content, activities, and learning objectives must be adjusted to reflect the difference in age and prior knowledge.

Identifying learning objectives for force and motion Start this session by explaining that this week you will switch from teaching content that enhances science understanding to discussing how teachers can foster the science learning of young pupils in elementary school. Ask yourself to reflect on the past two weeks and the content covered. Have them work in pairs and jot down ideas about how they could teach force and motion to children. What science topics would be relevant to teach in grades 1–8? Which principles and concepts do they need to establish as a foundation for learning science in high school and beyond regarding force and motion? What main ideas or concepts should be covered with these young children?

Identifying learning objectives for force and motion Possible answers are almost endless. This is not the time to approve or correct their ideas. Instead, have your Student Teachers discuss the ideas with each other. Have them explain their reasoning. Only interject if the discussion wanders too far off the topic. Record their ideas on the board or on a poster so that you can refer back to them in the next session. Also, consult Pakistan’s National Curriculum for General Science in grades 1–8. Have them analyse whether they have missed any relevant topics that they want to add now. You might want to form groups for different grade levels, for instance, grades 1–3, 4–6, and 7–8. Again, focus the discussion on only science concepts that relate to force and motion.