Here is a timeline outlining key events in the development of parachutes:
1595 - Croatian Fausto Veranzio designs a parachute and jumps from a tower in Venice. This is considered the first parachute design.
1617 - Swiss engineer Johann Jacob Oberkampf designs a parachute and jumps from a tower in Strasbourg.
1783 - Louis-Sébastien Lenormand makes the first witnessed public descent with a parachute, jumping from the Montpellier observatory in France.
1785 - Jean-Pierre Blanchard demonstrates a parachute in front of American revolutionaries including John Adams and Benjamin Franklin.
1797 - André Garnerin makes the first parachute jump from a balloon over Paris. He rode in a gondola that was separated from the balloon.
1837 - Robert Cocking dies attempting to test a parachute in England. His design was cone-shaped and did not slow his descent enough.
1870s - Small rigid parachutes are used to deliver mail and carrier pigeons by hot air balloons during the Franco-Prussian War.
1911 - Grant Morton makes the first successful parachute jump from an airplane over Venice, California.
1912 - Capt. Albert Berry jumps from a Benoist pusher aircraft at 1,500 ft over St. Louis, Missouri using a parachute packed into a knapsack.
1914 - The Parachute Regiment is formed by the Russian Air Force and becomes the first military parachute unit.
1918 - The United States Army forms an experimental parachute unit later named the Airborne forces. Germany also forms parachute units.
1922 - The first parachute jumping school opens in the United States. Students jump from hot air balloons and aircraft.
1930s - Parachutes are used to deliver airmail in the Mountains of the Moon in Africa.
1940 - Parachutes are issued to British RAF pilots during the Battle of Britain.
1942 - Nylon parachutes are designed to be more compact and replace silk. This allows paratroopers to carry their own chutes.
1960s - Ram-air parachutes are developed with cells that can be inflated to allow steering and gliding.
Present - Parachutes continue to evolve with new materials and computerized controls. They are used for military, space, and recreational purposes.
The scientific process is a systematic method of acquiring knowledge through different types of investigation and experimentation. It generally involves the following steps:
1. Asking a question - Students ask questions about how or why something happens that they want to explore. For this parachute lesson, students may wonder "How can I design a parachute to fall slowly?"
2. Researching/gathering information - Students gather background information to help them better understand the question and think of possible explanations or solutions. For the parachutes, this could include learning about gravity, air resistance, and drag.
3. Forming a hypothesis - Students make an educated guess or prediction about the answer to their question based on their background knowledge. For example, "If I use a large trash bag, the parachute will have more air resistance and fall slower."
4. Experimenting/testing - Students design and conduct controlled experiments to test their hypotheses. For this lesson, students test different parachute designs multiple times under the same conditions and measure the results.
5. Analyzing data - Students study the experimental data to look for patterns and determine what it reveals in relation to their hypothesis. They compare parachutes to see which designs slowed the descent more effectively.
6. Drawing conclusions - Based on the data analysis, students determine whether the evidence supports their hypothesis and allows them to draw a conclusion about the initial question. Students can conclude which parachute designs were most effective.
7. Communicating results - Students present their experimental process and results through papers, presentations, science fair projects, etc.
For this parachute lesson, students follow the scientific process to iteratively test and refine their designs. By experimenting with different variables and analyzing the effects, they gain insight into the science underlying parachute physics. The scientific process facilitates deeper hands-on learning.
Here is a glossary of relevant academic vocabulary relating to the scientific process and designing parachutes:
Air resistance - The friction between air and another material that slows the speed of objects moving through the air.
Analyze - Examine the data collected from an experiment closely and in detail to identify patterns, relationships, and conclusions.
Background knowledge - The information, concepts, and experiences someone already has about a topic prior to learning new information.
Conclusions - Judgments based on reasoning and examination of the data and evidence from an experiment.
Constraints - Limits or restrictions on a design problem, such as available materials or criteria that must be met.
Controlled experiment - A scientific test done under controlled conditions where only one variable is changed at a time so the effect can be traced to that variable.
Criteria - Standards or objectives a design must achieve to be successful.
Data - Measurements, observations, and facts collected during an experiment.
Dependent variable - The factor being tested and measured in an experiment. It depends on other variables. For parachutes, the fall time.
Drag - The force working against an object's movement through air or water. Parachutes create drag to slow falls.
Draw conclusions - Make logical judgments about the results of an experiment as they relate to the original hypothesis and question.
Hypothesis - An educated explanation or prediction formulated from background knowledge for how something works or why something happens.
Independent variable - The factor intentionally changed in an experiment to test its relationship to the dependent variable. For parachutes, sail size.
Iterative design - A process where prototypes are built, tested, analyzed, and improved through repeated cycles.
Observations - Detailed descriptive notes recorded throughout an experiment.
Parachute design - The size, shape, and materials chosen for a parachute to control its drag and slow descent.
Prototype - A working model built to test a design concept and demonstrate a solution.
Science fair project - A display and presentation where students pose a question, follow the scientific process to collect data through experimentation, and share their results.
Variables - Factors in an experiment that may influence the results. They include independent, dependent, and controlled variables.
Here are some typical dimensions and specifications for model rocket parachutes:
- Diameter - 12 to 24 inches is common for small model rockets. Larger high-power rockets may use parachutes 3 feet or more in diameter.
- Thickness - The canopy material is often ripstop nylon cloth with a thickness around 0.75 mil or 0.001 inches.
- Shape - Circle/round is the most common, but some are square or hexagonal.
- Suspension lines - Usually 4 to 8 shroud lines made of strong lightweight string or cord to attach the canopy to the rocket.
- Length - Suspension lines are typically 12 to 18 inches long to avoid tangling and give proper deployment time.
- Materials - Canopies are made from lightweight nylon, silk, or polyester. Lines are nylon, Kevlar or other fibers.
- Packed size - Small enough to fit in the rocket body, around 1 inch diameter x 5 inches long.
- Certification - Commercial parachutes are tested for reliability and strength standards specific to model rocketry.
The size matches the weight and speed of the rocket. Small 6-12 inch chutes are for lightweight rockets. Large high-power rockets need bigger chutes, sometimes stacked or tiered for multiple stages. The parachute slows the descent for a safe soft landing.
Here is a checklist for students to follow when designing a plastic bag parachute:
Parachute Design Checklist
☐ Choose parachute material
- Select lightweight plastic bag (trash bag, grocery bag, etc.)
☐ Determine canopy size
- Wider canopies create more drag to slow descent
- Recommend 24 inches or larger in diameter
☐ Choose canopy shape
- Circle, square, hexagon
☐ Add parachute suspension lines
- 4-8 lines evenly spaced to attach canopy to payload
- 12-18 inches long to prevent tangling
☐ Select line material
- Lightweight string, yarn, cord, ribbon
- Tie securely to canopy and payload
☐ Consider payload weight
- Larger/heavier loads need bigger parachutes
☐ Check for durability
- Material and lines should withstand force and speed of descent
☐ Test and refine design through multiple trials
- Modify variables like canopy size and shape if needed
☐ Measure and record results
- Time fall duration, observe flight behavior
☐ Analyze data and draw conclusions
- Evaluate effectiveness and compare designs
☐ Present parachute design and test results
- Explain process and performance
Following this checklist will allow students to methodically test parachute designs using the scientific process and engineering design skills. Let me know if you need any clarification or have additional questions!
No comments:
Post a Comment
Thank you!