What you'll need:
- A plastic bag or light material
- Scissors
- String
- A small object to act as the weight, a little action figure would be perfect
Instructions:
- Cut out a large square from your plastic bag or material.
- Trim the edges so it looks like an octagon (an eight sided shape).
- Cut a small whole near the edge of each side.
- Attach 8 pieces of string of the same length to each of the holes.
- Tie the pieces of string to the object you are using as a weight.
- Use a chair or find a high spot to drop your parachute and test how well it worked, remember that you want it to drop as slow as possible.
What's happening?
Hopefully your parachute will descend slowly to the ground, giving your weight a comfortable landing. When you release the parachute the weight pulls down on the strings and opens up a large surface area of material that uses air resistance to slow it down. The larger the surface area the more air resistance and the slower the parachute will drop.
Cutting a small hole in the middle of the parachute will allow air to slowly pass through it rather than spilling out over one side, this should help the parachute fall straighter.
We all know that whatever is thrown up always comes down. This is due to a force called gravity - which comes from the centre of the earth and attracts everything (physical things, living beings) to the surface of the earth. This is why we are able to walk on earth otherwise we would be flying around. Little children have great fun experimenting with this idea - especially when it comes to throwing things on the floor and expecting other people to pick them up!
BalasHapusOne of the objects that obey this law of gravity is the parachute. In real life, parachutes are very valuable since they used in emergency situations when people need to exit off a plane that is not functioning correctly. The parachute allows a person to land on the ground safely, but requires lot of training. The time taken to reach the ground depends on the weight of the person, the wind speed, parachute size etc
How the Parachute Works:
A parachute works on the principle of 'air resistance'. To understand this principle, try two things. Drop a stone and drop a feather from a certain height. You will see that the stone plummets down instantly, while the feather kind of floats down. When an object falls through the air, it basically creates a path by pushing aside the atoms and molecules in the air. A stone, with its heavy mass, has no problem doing this and so drops to the ground quickly. But a feather, which has little mass and a larger surface area, finds it harder to shove aside the atoms and molecules and this interference slows down its downward fall. This is exactly how a parachute operates – getting the air molecules to slow down the fall and thus make it safer.
Basic Parachute Aerodynamics
The descent rate of any body (such as a rocket) equipped with a parachute is dependant upon the drag force that the parachute develops, to counteract the gravitational force resulting from the payload's mass.The drag force is dependant upon
1) the dynamic pressure created by moving air striking the parachute canopy (and which keeps the parachute inflated)
2) the diameter of the parachute, which determines the area over which the dynamic pressure acts
3) the drag coefficient, Cd, of the parachute. Dynamic pressure is a function of velocity and air density, which in turn is dependant upon altitude and temperature.
make sure that the design is safely, the air resistance needed.
BalasHapuswhat is the objective of this activity ?
just make a fun?
or real parachute?
hehe