Forces

Why do things move/not move? What are different ways we can make something move? What factors affect movement? These are just a few questions that we will attempt to dive deeper into through today's experiment.

Why do things move?
There are many reasons as to why an object moves and keeps moving, such as:

• Gravity
• Energy (kinetic and potential)
• Friction 
• Material of object

Why do things not move?
Contrastingly, objects also do not move as a result of:

• Friction
• Balanced forces (i.e. block on table)
• when the forces are unbalanced, this is when movement occurs
• Gravity

What are different ways we can make something move?
Because we now have some understanding of why things move/don't move, we began to think about things that cause objects to move:

• Push
• Pull
• Air/water pressure
• Application/absence of a force

What factors affect movement?
Making something move and keeping something moving are two different things. Here's what we came up with:

• Gravity
• Forces of other objects
• Surrounding air/water
• Friction
• Weight
• Height
• Material of object
• Hollow/not

To test these ideas, we decided to see what would happen when we dropped a bouncy ball versus a ping pong ball:

Claim: Unbalanced forces make things move.
Evidence:

• say you're holding a bouncy ball!
• gravity is the downwards force
• your hand is the upwards force
• the ball is NOT moving because forces are EQUAL
• HOWEVER: If you let go of the ball, it will fall until it hits another object that will help balance the forces again

We also attempted to design a rocket to control the forces:

• 1st attempt at building a rocket:
• We inserted a straw into a balloon and taped it shut. We thought that the straw would force the balloon to release its air in a specific direction, rather than flying all over the place. It was unsuccessful; the balloon just sat on the table and the air was released slowly through the straw.
• This attempt was unsuccessful because the straw was too narrow for the balloon to release its air.
• 2nd attempt at building a rocket:
• Next, we inserted a small metal ball to weigh the balloon down while the air was released. This attempt was unsuccessful, as the ball plugged the balloon so that no air could be released. The balloon fell to the floor.
• This attempt was unsuccessful because the ball was too heavy. Gravity pulled it to the base of the balloon, where it plugged the hole.
• 3rd attempt at building a rocket:
• Finally, we placed a small styrofoam ball into the balloon. This was successful! Because the ball was light and porous, it weighed the balloon down just enough for it release its air and fly in one direction (straight forward at about a 45 degree angle). The balloon then hit a wall and completed releasing its air until it hit the ground.
• Forces involved: Gravity, Energy (potential: the air pressure in the shut balloon; kinetic: the force created by the air escaping), Friction (movement of the balloon through the air and air rubbing against the mouth of the balloon as it's escaping)