Week 4: Gravity/Swing

 

Week 4

Big Question:

Main Takeaways on slide and gravity:

• Weight is how much gravity is pulling down on an object. 
• When thinking about how things fall weight matters. But air drag also has a huge effect. a crumpled piece of paper, and a loose crumple of paper fall at different rates but have the same mass. The tight crumpled piece of paper has less air drag than the loose paper. 
• Air drag can cancel almost all or most of gravity on the loose paper.
• The heavier an object is the longer it takes to slow down or speed up.
• Gravity does pull harder on objects with more mass, but adding air drag and the time it takes for heavier things to speed up and slow down cancels the forces and makes it even.
• A rider who weighs more will finish the slide at the same time as a light rider. Because the time it takes to speed up or slow down an object of greater mass, and air drag cancels out the competition.

How can we support play that is exciting and not dangerous?

What affects a riders speed down a slide?

What affects how long it takes a swing to go back and forth? 

    We tested dropping several different types of balls to see which would hit the ground first. We looked at the drag and air resistance of each one of the objects that were dropped, and how that force affected it. If we could ignore air resistance we would see that all objects fall at the same rate. Kids think that heavier objects fall faster because sometimes we see it does between a brick and a feather. But that is because the feather catches more air. Then we connected this to the slides from the past week, why does the riders weight not matter. Gravity pulls harder on more massive objects. The more massive an object is, the harder it is to speed up or slow down. The effects cancel each other out, gravity pulls harder on a massive object but it is harder to speed up so then they cancel out and can fall at the same rate as others that may not weigh as much. 

    We then started discussing what affects how long it takes a swing to go back and forth. We made a list of all of the possible variables that could have been tested. 

Thursday Lecture:

    To begin our lecture we once again reviewed what occurred during lab, focusing more on the force and energy lens. We dove into and analyzed what we found in the riders weight, and the rope length. We found out that riders weight does not affect the period of a swing. Newtons first law tells us that force (push/pull) is required to speed up, slow down. Newtons second law tells us that larger masses are harder to accelerate. F=ma is the equation for acceleration. 

    Then we discussed the energy lens of motion. energy is manifested in many ways such as movement, light, heat, etc. Energy can be transferred from one system to another, it is never created nor destroyed. At the bottom of a swing there is kinetic energy, at the top there is potential gravitational energy. Potential energy increases with height, kinetic energy decreases with height. More speed = more kinetic energy, more height is more gravitational potential energy. Although two swings with different lengths, they have the same max speed. But the longer swing travels farther than the shorter one. Weight does not matter on a swing but length of the swing does affect the period. As a swing collides with air particles speeding the particles up it slows down the swing, the collision transfers energy from the rider to the surrounding air.