Engineering4kids/Nature and engineering
Contents
Retracting Cat's Claw
There are many examples of engineering in nature. A cat's retractable claws make use of a xx. When not needed for hunting or self-defense, climbing, kneading, or for extra traction on soft surfaces, the cat's claws stay tucked in the fur and skin between its toe pads.
Design Challenge : sharp and ready to use
It is hard to improve on nature, but there is much to learn from understanding how these mechanism work. Think about the cat's paw as a design challenge. Each question corresponds to a step in the Engineering Design Process. A cat needs to use its sharp claws for some activities, without wearing them down when not in use. This retractable claw arrangement meets the needs.
- What? (Ask questions, understand the need, identify the problem)
Cats extend their claws for hunting or self-defense, climbing, kneading, or for extra traction on soft surfaces. The claws stay sharp because they are not worn down when they are just walking normally. By retracting them when not needed, it reduces their exposure and wear. By waiting to extend its claws until they are needed, the cat prevents excessive noise from the claws contacting a hard surface.
- So What? (Imagine, brainstorm, explore)
The curve of the claw is important. As the cat grows and uses its claws, they will grow too. Imagine the claw wasn't curved. Would the rotating extension be as effective if they were straight? Would the claw then need a larger range of motion to get out of the way when not in use? Examine the design of the claw and define traits that work together to make the claw function efficiently.
- Now What? (Plan, design)
The claws need to be able to move out far enough to contact surfaces and hold tightly. The cat may need to extend the claws in only one foot.
- Do It (Create, try it out)
Cat's claws are held in place by ligaments, but are able to be rotated outward through the use of specific muscles and tendons. The claw material stays sharp. It can be sharped as it wears down and grows.
- If this then what? (Improve, make it better)
Can you improve on the design of the claw? Can you spot anything that would make the claw work better? Analyzing a pre-existing design and improving upon it after seeing how it performs is a big part of engineering. There are many new man-made materials that have the same properties as cat's claws.
Engineering vocabulary, concepts
Show and Tell
Now it is your turn. Here are some challenges for you to work on...
- find some illustrations of cat paw bones and tendons
- recreate the claw retraction action with Connects or LEGO xx
- using CAD or drawing software to make your own model of the claw retraction mechanism
- learn about man-made materials that are strong and light like cat's claws
- build a working prototype out of the materials provided
- What materials or tools do you need to improve your prototype? How could you make your prototype function better than a real cat's claw?
Learn more...
- Cat - includes a description of paws and claws
- retracted claw and extended claw - diagrams
Body Parts as Machines
introduction
Design Challenge : statement
Each question corresponds to a step in the Engineering Design Process.
- Ask (What? Ask questions, understand the need, identify the problem)
- Imagine (So what? Imagine, brainstorm, explore)
- Plan (Now what? Plan, design)
- Create (Do it. Create, try it out)
- Improve (If this then what? Improve, make it better)
Engineering vocabulary, concepts
Show and Tell
Now it is your turn. Here are some challenges for you to work on...
- demonstrate how artificial body parts are used, and describe their limitations
Learn more...
Galloping horse
- Contrary to the old "classic" paintings of running horses, which showed all four legs stretched out in the suspension phase, when the legs are stretched out, at least one foot is still in contact with the ground. When all four feet are off the ground in the suspension phase of the gallop, the legs are bent rather than extended.
- In 1877, Leland Stanford settled an argument about whether racehorses were ever fully airborne: he paid photographer Eadweard Muybridge to prove it photographically. The resulting photo, the first documented example of high-speed photography, clearly showed the horse airborne. more...
Design Challenge : Four feet in the air
This was an problem that had interested engineers and biologist alike. But how to determine the actual mechanism of the horse's gallop? How to prove it with the technology available in 1877? Each question corresponds to a step in the Engineering Design Process.
This is a two part challenge. There are mechanics involved in the horse's gallop gait. And there is the challenge of using very basic camera equipment to prove it.
- What? (Ask questions, understand the need, identify the problem)
Mr. Stanford believed that horses became airborne when they gallop - all four feet are in the air at the same time. There weren't any video cameras yet. Basic cameras could take one picture then they had to be reloaded.
- So What? (Imagine, brainstorm, explore)
One video camera takes many pictures one right after another. Mr. Muybridge, the photographer used xx cameras that each took one picture.
- Now what? (Plan, design)
The cameras would need to be arranged and set up so they would take a picture at a very precise moment - a fraction of a second after its neighbor.
- Do It (Create, try it out)
Getting everything set up was a big job. The cameras were stationary so the horse had to gallop in front of them.
- If this then what? (Improve, make it better)
Now there are video cameras that take high speed photographs.
Engineering vocabulary, concepts
Show and Tell
Now it is your turn. Here are some challenges for you to work on...
- create a model to show the movement of the horse's legs in a gallop.
Learn more...
- Horse gait - Gallop - description, images, video
Re-engineering mosquitos
In this video, Biotech entrepreneur Hadyn Parry who leads a science start-up, talks about developing GM (genetically modified) insects to fight dengue fever.
Re-engineering mosquitos to fight disease
Each question corresponds to a step in the Engineering Design Process.
- What? (Ask questions, understand the need, identify the problem)
Dengue fever is spread by mosquitos. Chemical spraying is expensive and causes other problems. Many other alternatives have been tried but don't work very well. The problem is wide spread so the solution has to available in many parts of the world.
- So What? (Imagine, brainstorm, explore)
The mosquitos are the problem so eliminate or significantly reduce the number of mosquitos. The solution need to be low cost. It must be easy to use and not require electricity. It should not introduce new problems.
- Now what? (Plan, design)
Biotech engineering is relatively new. The work must be done in special laboratories. The modified mosquitos need to be transported to the infected areas.
- Do It (Create, try it out)
Make small batches of re-engineered mosquitos. Send them to an infected area to test the effectiveness or this solution.
- If this then what? (Improve, make it better)
There are disease-causing mosquitos in rural areas and in cities.
Engineering vocabulary, concepts
biotech engineering, genetic modification
Show and Tell
Now it is your turn. Here are some challenges for you to work on...
- Research dengue fever and describe some of the ways people have tried to prevent the spread of this disease
- Give a presentation about bio-engineering, its history, and some of the work that is being done
- Find out more about Genetic Modified Organisms (GMO) - the plants, animals and insects that have been genetically engineered
Learn more...
- Biotech entrepreneur Hadyn Parry leads a science start-up that develops GM insects to fight dengue fever.
