Engineering4kids/Nature and engineering

== 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.

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.
 * What? (Ask questions, understand the need, identify the problem)

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.
 * So What? (Imagine, brainstorm, explore)

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.
 * Now What? (Plan, design)

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.
 * Do It (Create, try it out)

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.
 * 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...
 * 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
One of the earliest uses of photography as a scientific research tool took place in the late 1800s. How did horses gallop? Did all four feet come off the ground at the same time?


 * 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.

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.
 * What? (Ask questions, understand the need, identify the problem)

One video camera takes many pictures one right after another. Mr. Muybridge, the photographer used xx cameras that each took one picture.
 * So What? (Imagine, brainstorm, explore)

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.
 * Now what? (Plan, design)

Getting everything set up was a big job. The cameras were stationary so the horse had to gallop in front of them.
 * Do It (Create, try it out)

Now there are video cameras that take high speed photographs.
 * 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...
 * 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 a single year, there are 200-300 million cases of malaria and 50-100 million cases of dengue fever worldwide. So: Why haven’t we found a way to effectively kill mosquitos yet? Hadyn Parry presents a fascinating solution: genetically engineering male mosquitos to make them sterile, and releasing the insects into the wild, to cut down on disease-carrying species.

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.

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.
 * What? (Ask questions, understand the need, identify the problem)

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.
 * So What? (Imagine, brainstorm, explore)

Biotech engineering is relatively new. The work must be done in special laboratories. The modified mosquitos need to be transported to the infected areas.
 * Now what? (Plan, design)

Make small batches of re-engineered mosquitos. Send them to an infected area to test the effectiveness or this solution.
 * Do It (Create, try it out)

There are disease-causing mosquitos in rural areas and in cities.
 * If this then what? (Improve, make it better)

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.


 * Biotechnology
 * genetic modification
 * dengue fever