Scientific Thinking

Scientific Thinking © Pinellas County Schools 05-06

Science Inquiry Skills • Observing, hypothesizing, measuring, classifying, collecting and interpreting data, predicting, experimenting, inferring and communication

Topic Statement • I am interested in studying ________________________________ sports? weather? animals? plants? Music sound?

I am interested in studying: aerodynamics parachutes electricity how lights work force and motion simple machines plate tectonics volcanoes salinity of water the ocean convection currents cooking chemistry mixtures and solutions

Science Content Statement • Learn more about your topic from the library, internet, textbooks, and write down what you learned.

Parachutes The main idea behind a parachute is that this device slows down a falling object. It does this by creating a drag or air resistance. Air Resistance is a frictional force experienced by objects as they move through air or as air flows around them. It generally opposes the motion of the object or the air flow around it, and is created by the air rubbing on the outside surface of the object. When the parachute canopy is opened, the air molecules move farther out creating drag. The more drag that is created the slower the object falls down. The force acting on the falling object is gravity. Gravity is the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface. If something or someone falls from the sky gravity will quickly pull them to the Earth’s surface. A parachute is used to slow this effect down. The drag or air resistance depends on the surface area of the object. Surface area is the measure of how much exposed area an object has. Parachute canopies have large surface area which creates enough drag for its passenger. Shapes also have an effect on the efficiency of the parachute. Modern designs have rectangular or tapered shapes. Tapered parachutes are in parachute sports. They have more fabric cells to enable more control and speed. Rectangular ones on the other hand are used for recreation. These are safer and are more frequently used in training programs for students .

The force making the parachute fall is gravity. Gravity is what holds everything on the Earth and keeps the Earth in its place in the Solar System. Gravity forces the parachute down but air resistance pushing up on the flat surface of the parachute causes it to fall slower to the ground. The air is forced to move around the surface.

Research Question • How does _____________ effect ________________? OR • What is the affect of _______ on ___________?

Research Question How does the surface area of a parachute effect the rate at which the parachute falls to the ground? What affect does the size of a parachute have on how fast it falls to the Earth?

Prediction • List 3 ways the experiment might end up.

The smaller surface area will cause the parachute to fall at a faster rate. • The larger surface area will cause the parachute to fall at a faster rate. • The surface area will not affect the falling rate of the parachute.

The smaller parachute will hit the ground faster. • The bigger parachute will hit the ground faster. • The parachutes will all hit the ground at the same time.

Hypothesis • The hypothesis is a statement that predicts what you think will most likely happen in the experiment.

I believe the smaller the amount of surface area the parachute canopy has the greater the falling rate in seconds. I believe the smaller parachute will hit the ground faster than the bigger parachutes.

Manipulated Variable • The one thing (or object) you will change in the experiment Like the amount of water

The surface area of the parachute. The size of the parachute.

Responding Variable • Identify what you will measure to see if it is effected ( in the experiment ) like the height of the plant

The falling rate of the parachute in seconds. How long it takes the parachute to fall to the ground.

Set-Up Conditions • List all the things (materials / procedures ) that will remain constant to ensure a fair trial. changing the amount of water Everything else needs to be constant

Two pieces of string 12 in. long to attach to the four corners • Sticky dots to attach the string to each corner • One paper clip to hang from the middle of both strings • Measuring tape to drop the parachute from the exact height each time. • A second story balcony from which you drop the parachute • A stopwatch to time the drop

Materials • A list of items that will be used. Include size, quantity, and descriptions such that some one else could duplicate your project.

String or twine • Paper clips • Sticky dots • Paper napkins • Measuring tape/ meter stick • Stopwatch • Science Journal for recording

Experiment Directions • Step-by step list of what you did (or how each item will be used) in your material list and the exact order it was done.

Cut a paper napkin in half, and then cut another in quarters to have the three different size parachutes. • Cut your twine into 6 12-inch pieces • Attach one piece of twine to the corner of one uncut, unfolded napkin with a sticky dot. Attach the other end to the opposite corner. Do this again with the two empty corners and another piece of string. Do this for each size parachute. • Hang the paperclip in the middle of the two pieces of string where they meet. Make sure the paperclip is securely attached. • Go to the second story and measure the exact height you will drop the parachute from to the ground. Have a parent or partner stand on the ground directly below you with the stopwatch. • Hold the parachute by the middle of the canopy, line up the exact drop point, and release the parachute. • As you release the parachute have a parent or partner start the timer when you say start. • The parent or partner can then stop the stopwatch as soon as any part of the parachute hits the ground. • Record the time in your journal. • Repeat this trial 11 times with each size parachute.

Data Collection • An organized and complete account of everything that was measured and observed in the experiment (using metric units). There should at least 10 or more trials.

More on Data Collection… • Data is usually presented in a chart form. • Chart should include averages (mean) of the trials given.

Graph • A mathematical picture of the data, using (mean) averages to plot the data in the experiment.

Falling Rate of Parachutes in Seconds

Experiment Results • Use the data and graphs (from the experiment) to explain what happened in the experiment. • Did your manipulated variable affect your responding variable? (if so explain how)

During this experiment with each drop of the parachute the results were the same: the less surface area the parachute had, the smaller the amount of drag or wind resistance, and the faster the parachute fell to the ground. The small parachute fell to the ground at an average rate of 10.19 seconds, the mid-sized parachute fell at an average rate of 26.9 seconds, and the largest parachute fell at an average rate of 49.33 seconds. My manipulated variable, the surface area of the parachute, did effect my responding variable, the amount of time it took the parachute to hit the ground.

Every time we dropped the parachute the same thing happened: the smaller the parachute, the faster the parachute fell to the ground. The small parachute fell to the ground at an average rate of 10 seconds, the mid-sized parachute fell at an average of 27 seconds, and the largest parachute fell at an average of 49 seconds. My manipulated variable, the size of the canopy, did effect the amount of time (my responding variable) it took the parachute to hit the ground.

Experiment Conclusion • Explain whether or not you data supports, or fails to support your hypothesis. (gives fact / reasons from your experiment)

The data I collected during this experiment proves my hypothesis that the more surface area the parachute has the more air resistance it will have and the parachute will fall to the ground slower. Therefore, the smaller the parachute canopy the faster a person would fall to the ground. The larger canopy consistently took longer to hit the ground then the mid-sized or the smallest canopies. The smallest canopy took the shortest amount of time to hit the ground in every trial.

My hypothesis was that the smaller parachute will hit the ground faster than the bigger parachutes. My experiment proved that my hypothesis was right. The smaller parachute always hit the ground first and faster than the other two sizes of parachutes.

Experimental Real World Uses • A description of ways, places, or situations where the information from your experiment might be useful.

Parachutes are used in real world situations all of the time. They are used in times of war to airlift troops, they are used in times of famine to feed starving populations, and they are used for recreation. In times of war parachutes are a quiet and covert way for troops to land behind enemy lines. We have been using paratroopers since WWI in this country. These parachutes are often small to enable soldiers to maneuver more easily. In times of famine we use parachutes to drop food in places that are inaccessible by truck or plane. These parachutes have to be very large to accommodate the heavy boxes full of food and supplies in drought stricken areas and to ensure things are not damaged! Finally many people consider the use of parachutes in skydiving a fun and dangerous sport for recreation. These parachutes are lightweight and relatively small. I also found research to support the use of a suit with an even smaller surface area like that of a flying squirrel. This allows a lot of freedom o the skydiver and allows for incredible speed. They are attempting to land without another parachute to cushion the fall!

Parachutes are used in the real world. There are three places they are used. First they are used by soldiers. They jump out of planes to land behind enemy lines. Second, they are used by the government. The government uses them to drop food for starving people in places cars and trucks cannot go. Finally they are used by skydivers. These are people that jump out of planes for fun. Anyone can go skydiving and watch the parachute work!

Experimental Reflections • A paragraph which includes thoughts, concerns, discoveries, or further questions to explore. • What might you do differently next time? (give reasons)

While attempting this experiment I discovered that a different material might be a better choice next time. Paper napkins have a tendency to tear easily and then another parachute must be made possibly affecting the integrity of the experiment. I also considered changing the experiment next time to discover how the material effects the falling rate of the parachute. I would also consider adding more sizes for experimentation experiences. Overall I was happy with the experiment and my results. I can definitely expand on this experiment next time I attempt it.

Presentation Board for Experiment Research Question Prediction Hypothesis Science Content Statement Manipulated Variable Responding Variable Set Up Conditions Data Collection Graphs Results Statement Conclusion Statement Real World Uses Directions Materials Diary

Scientific Thinking