Educator How-To: Be your own knight in shining armor with homemade chain maille

When people think of knights, they generally think of armor, too. The plate armor most associated with knights was actually a fairly recent invention. Armor started as quilted shirts and thick leather pieces to cover arms and legs (if you were fortunate enough to afford it!).

Chain maille was a pretty fantastic innovation for the time, but it had its drawbacks, too. It was heavy and cumbersome and only as strong as each individual link. Because the links were made of steel or iron, they rusted quite readily, and those rusty links were the proverbial “chinks in the armor.” They were points of weakness that might allow a sword point or arrow to penetrate. 

The job of armor maintenance was given to young boys that might otherwise be underfoot. To start, the armor was placed in a barrel of sand and sealed up. The boys would then roll the barrels back and forth across the yard and the sand would scour the blood and sweat and rust off the links. Even a well-maintained chain maille shirt would need repairs quite often and the color on even the best of days would be a dull dark gray.

Further innovations led to the plate armor that we know today, but even then, it wasn’t always so shining. Here is a suit of armor that belonged to Henry VIII. 

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Beautiful? Yes. Well-crafted? Yes. Shining? Not so much.

Don’t be fooled into thinking that body armor like this was a strictly European invention.  Most cultures that engage in warfare have some sort of armor to counteract the weapons. Some of the armor is ceremonial, but more often than not, it is clever and particular to the local environment. 

The Maya and Aztec, for example, wore knee-length jackets of tightly-woven quilted cotton called ichcahuipilli. The jackets were soaked in salt water and then the water was allowed to evaporate. The salt left behind would crystalize between the quilted portions of the jacket, creating small, thick, sturdy plates of protection which were effective against arrows, atlatl darts, obsidian swords and batons.

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They didn’t have cotton in Micronesia, so on the islands of Kiribati, they used what they did have: coconuts. Helmets, leg coverings, shirts and chest protection were made from tightly-woven coconut fibers as protection against another natural resource: sharks (or more accurately, shark teeth). The teeth of the sharks were drilled in the roots and then attached to the base with bits from the veins of the coconut leaf or human hair. The shark-tooth swords were intended to disembowel an enemy or open a major artery so he would bleed out. Yikes!

Want in on all this exciting armor action? You’ve got two options!

Option 1: Bring your crew down to see Magna Carta before it leaves on August 17th.  You have three short weeks! If you want to bring a school group or day care, be sure to contact fieldtrips@hmns.org to get the school rate. You will also want to consider coming on a Friday mornings at around 11.

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Option 2: Can’t make it to us? Then try your hand at making your own armor. Sort of.  Here’s a pretty easy chain maille bracelet you can make at home. It won’t offer you much protection but it will allow you to practice your technique before trying something a little more complicated.

Materials:

-Jump rings or chain maille rings (The bigger they are, the less work for you.)
-The clasp of your choice or a piece of leather or ribbon to tie the bracelet ends together
-2 pairs of jewelers pliers (or needle-nosed pliers if you are in a pinch)
-A tape measure or piece of paper to measure your wrist

Procedure:

  1. Measure how long you want your bracelet to be using a tape measure (or even a piece of paper). The standard size for women is about 7 inches and the standard size for men is about 8.
  2. Open several of your jump rings. To open them, you DON’T want to pull them apart.  Instead you want to twist them open. If the individual rings start off as an “O” shape, you don’t want to make them into a wide-mouthed “C”. Instead, you want to slide the ends away from each other, one towards you and one away from you. Because of the way the rings are made, they naturally take that shape, so that should help you get started. If your rings lay flat when opened (rather than in a twisty shape), you will need to try again! Once you have a pile of open rings, things get a little trickier. You can keep up though. I believe in you.

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  3. The next step is to put four closed rings on an open ring and then slide the open ring back into the closed position. Then repeat this step over and over. You will need probably 10 of these 4-in-1 sets for a 7-inch bracelet.

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  4. Once you have the 4-in-1 sets made, you will need to use your pliers to separate out two rings from the four. The set should hang from your pliers as two rings, with one ring in the middle and two more rings at the bottom. You are then going to feed an open ring through the top two rings. Shift your pliers around so that you are now holding onto that open ring.

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  5. Using your other set of pliers, pick up two rings on another 4-in-1 set. Loop those two rings through the open ring (effectively creating a new 4-in-1 set) and then close the open ring. You should have created a small chain at this point. Great job!

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  6. Repeat steps 4 and 5 until you have 4 or 5 small chains. I am doing 4, but I have pretty small wrists.

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  7. Getting close to being done! You will need to link these small chains in exactly the same way you did the sets. Take two rings from the top of one small chain and put them on an open ring with two rings from the top of another small chain.
  8. Now, repeat step seven with your longer chains!
  9. Finish up by adding a single jump ring to each end. This will let you tie the two ends together, or you can add a clasp to that last ring before you close it up. You’re done!

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Educator How-To: The eyes have it in this DIY optical illusion

Your eyes are amazing sensory organs. They help you understand shape, color and form, judge distance and alert you to potential dangers. What you perceive as “seeing” is actually the result of a complex series of events that occur between your brain, your eyes and the world around you.

Light reflected from an object passes through the cornea of the eye and moves through the lens, which focuses it. The light then reaches the retina at the very back of the eye, where it meets a thin layer of color-sensitive cells called the rods and cones. Information from the retina travels from the eye to the brain via the optic nerve.

Because eyes see from slightly different positions, the brain must mix the two images it receives to get a complete picture. The light also crisscrosses while going through the cornea so the retina “sees” the image upside down. The brain then “reads” the image and turns it right-side up.

The rods and cones are what you call photoreceptors. When they are overworked, they lose sensitivity. Normally the small movements of your eyes that you make unconsciously, or regular blinking, will keep these photoreceptors sharp and happy. If you are looking at a large enough image, where your eyes can’t rest, or if you purposely hold your eyes still, you will tire out your poor rods and cones and they will adapt to this overstimulation by no longer responding. When you move your eyes to a blank space, your worn out photoreceptors create an “afterimage”.  An afterimage is where your eyes produce a ghost image, like when you stare at something a little too bright and you see dark spots in your field of vision. In an afterimage, light portions of the original image are replaced by dark portions and dark portions are replaced by light portions.

Try this out for yourself by doing the following activity. 

You will create the Texas state flag in some unusual colors. After you stare at this incorrectly colored flag and have worn out your photoreceptors, looking at a blank wall will create a ghost image of the Texas state flag in red, white and blue!

Activity:  Negative Afterimage

Materials:
Scissors
Glue
Paper
Green construction paper
Black construction paper
Yellow construction paper 

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Procedure:

1. Cut your green and yellow papers in thirds, width-wise.

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2. Cut a star out of the middle of your yellow piece.

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3. Glue the yellow piece to one end of the black piece.
4. Turn the black paper so that your yellow piece is placed on the left.

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5. Glue the green piece to the bottom of the black piece.
6. Trim off any extra green.

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Now stare at the flag for a minute or so. Try not to have much in your peripheral vision so that you can concentrate on the flag.

Look away from the flag at a neutral colored wall or piece of paper.  You should be able to see the flag in red, white and blue!

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Have a school group and want to know more about how your eyes work?  Sign up for an Eyeball Dissection with our Labs on Demand.  These labs make a great addition to a field trip, but are also available to come to your school.

Interested in knowing more about how your body works?  Visit Body Carnival, a carnival-themed interactive exhibit that explores the connections between perception and the laws of physics in the human body, at HMNS Sugar Land. Enjoy learning about the human body while investigating force, pressure, light, and color. Crawl through a giant artery to see and hear the effects of restricted blood flow, test your balance in the 10-foot Dizzy Tunnel or don a pair of vision-distorting goggles and discover how sight affects your ability to walk straight. There’s a lot to explore!

 

Educator How-To: We’re batty for ornithopters

Bats have frightened, awed, and inspired for millennia. Leonardo da Vinci used the bat’s amazing wing structure as inspiration for his version of the ornithopter — a machine which flies using flapping bird-like wings. No one knows for sure if he ever built or tested his invention, but Cardanus, a contemporary of Leonardo wrote that he had tried, “in vain”, to get the orinthopter aloft.

A sketch of Da Vinci’s ornithopter

Here is a version of Leonardo’s creation that you can try your hand at constructing and flying. Our version is technically a glider, but looks much the same as Leonardo’s ornithopter design.

Materials:

  • Cardstock copy of orinthopter template
  • Large plain craft stick
  • Paper clips – large and regular size
  • Craft glue
  • Scissors
  • Scotch Tape ™
  • Markers
  • Thin hemp-type string
  • 18th inch hole-puncher
  • Bat specimen or pictures of bats
  • Picture of Leonardo’s orrnithopter

Building the Ornithopter:

  • Display the picture of Leonardo’s ornithopter and discuss how he came up with the design idea after spending a great deal of time observing birds.
  • Study the bat specimen and/or bat pictures. Compare and contrast the bat wings with the ornithopter wings: Are the wings more bird-like or bat-like?
  • Color a large craft stick using a brown marker.
  • Color the wings and tail on the orinthopter template and carefully cut out the pieces.
  • Give the wings shape by closing the small V-shaped notch on each wing so that both pieces touch and then securing on the underside with transparent tape.
  • Using craft glue, attach the wing and tail pieces to the craft stick as illustrated by the picture below. Allow time for the glue to dry.

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  • Next, bend the wings up along the large V in the wing pattern and carefully crease.
  • Use a 1/8th inch hole-puncher to make small holes just to the inside where the wings were taped to give them shape.
  • Use a piece of thin string to create a loop through the holes with a loose knot to secure it in place. This serves to keep the wings from spreading too far and to adjust the wings up when tightened.

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  • It’s time to test the ornithopter! Make different sized paper clips available. Use these to properly distribute the weight of the ornithopter for better flight.
  • Spend time re-engineering the after the primary test flight.

Educator How-To: Teaching tessellation, symmetry & point reflection

Tessellations — tiling a plane using geometric shapes without overlaps or gaps — are a pretty fun way to teach students about shapes, symmetry, reflection and rotation. Plus, they require the most minimal of supplies!

Materials:
•    Plain 3″ x 5″ index cards
•    Scissors
•    Scotch tape
•    Blank white paper
•    Optional: colored pencils/crayons, etc.

Procedure:
1.    Draw a simple design from one corner of the sheet to an adjacent corner. (Do not draw diagonally). Stress to the students that they must draw from corner to corner on this first attempt. Do not stop halfway across!

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2.    Cut on the design line, being sure to have two pieces when done. NO TRIMMING ALLOWED.

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3.    Slide the cut piece across the sheet to the opposite side and tape the straight edges together. The corners of the original card and the cut piece should match perfectly.

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4.    Repeat the procedure for one of the short side sides. Key points to remind students:

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  • Do not flip the cut pieces of your index cards
  • Do not overlap the edges of your cut pieces
  • Make sure you only cut one long side and one short side. The cut pieces will attach to the opposite straight edges
  • Cut exactly from corner to corner
  • When taping your cut piece to a straight edge, make sure everything lines up

5.    Once you have a completed pattern for your tessellation, place it anywhere on a piece of paper and trace around it. This example is squared up with the original index card edge and the paper’s edge, but this is not necessary.

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6.    Move your pattern so that its edges match up with the outline you drew. If done correctly, they should fit snugly together like a puzzle piece, leaving no gap. Trace around your pattern when it is in position.

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7.    Continue moving and tracing your pattern until your page is filled with your pattern’s outlines.

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8.    For extra fun, and in homage to M.C. Escher, you can add some details to your artwork!

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Background:
A tessellation is created when you cover a surface with a repeating pattern of shapes, making sure there are no gaps or overlapping pieces. The word “tessellation” comes from the Latin word “tessella.” Tessella were tiny squares of stone that were used to make large mosaics. The patterns for these mosaics were usually intricate and often geometric. This tradition continued in many different cultures, but is particularly well recognized in the Moorish artwork of Morocco and southern Spain. More recently, M.C. Escher applied the concept of tessellations to less geometric and more fantastical shapes. You may also recognize tessellations in nature in the form of bee hives, snake scales, and the outside of a pineapple.

Regular tessellations are made by repeating squares, hexagons and equilateral triangles – all regular polygons. If you figure out the interior angles of these three shapes, you might note something interesting…

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All of these numbers — 60, 90 and 120 — are evenly divisible into 360 degrees. This means that they fit together extremely well and make filling a space easy, either while touching themselves, as in triangle to triangle, or each other, as in triangle to hexagon. When you combine these three shapes to make a pattern, you are creating a semi-regular tessellations.

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When creating tessellations, it is important to understand reflection symmetry, rotational symmetry and point reflection.

Reflection symmetry occurs when you can easily divide an item into two and the two halves are identical. The dividing line is referred to as the line of symmetry.

With rotational symmetry, the polygon is rotated around a central point, without leaving the surface you are working on.

Point reflection occurs when you create a mirror image of a shape. Reflection is not terribly important if you are using the shapes in a regular tessellation as they are all perfectly symmetrical when divided in two. Reflection becomes much more important when you are using fluid shapes. This concept is important for students to understand as they make their tessellations. Their shapes won’t fit together correctly if they have been reflected!

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