Secondary Science- Forces
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Forces
Researched into students ideas about forces causing horizontal motion and friction. Based on practical experiences. Limited prior knowledge on forces transmited through solids, liquids and gasses. Limited knowledge on pressure.
Polled 7-9 year olds - Think of forces in terms of feelings and anger - some 7-8 y.o. saw force as something that causes something else to move
- Limited knowledge of force stopping movement
- usually associate force with living things and the physical activity needed to move something
- don't recognize static forces
Student main ideas on forces - if there is motion, these is a force acting - if there is no motion, then there is no force - there cannot be a force without motion - when an object is moving, there is a force in the direction of the motion - a moving object stops when its force is used up - a moving object has a force within it which keeps it going - motion is proportional to the force moving it - a constant speed results from a constant force
Students saw force a single thing, not a combined interaction between multiple forces
Erickson and Hobbs: looked at forces in pairs (push/pull) - 6-14 y.o. could distiguish push and hold Some Secondary sci students do not know how to properly use arrows to show force or identify all of them. Most don't get magnitude.
Forces in Pairs Multiple surveys of high school students in multiple countries showed that students did not understand paired forces and how they balance. - see that only one force is acting on a static object -if there are two forces then one is stronger than the other
Forces acting together- Net Forces and Equilibrium - one force is always stronger to cause movement - don't get that multiple forces can cancel out a strong force
Pressure: specifically air pressure -Students only see air pressure with moving air not static -pressure increases with depth
Tuning forces - even young studetns know that on a see-saw the bigger weights move farther down on the see-saw and that if the same weight is moved farther from the center, the farther down it will go
