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Seeing a rainbow outside is always an amazing and wonderful experience. Many of us wish that we could see a rainbow more often.

With a glass prism, the colors of the rainbow can be brought inside and enjoyed every day that the sun shines through the window.

This tutorial will show how to make a sturdy prism pedastle that will support a prism in the correct position to create rainbow colors indoors when placed in a sunny window.

The rainbow colors can also be used as an interesting way to note seasonal solar movement over time.

Step 1: Design Considerations

The phenomenon of seeing the colors of the visible spectrum is truly amazing and is accomplished naturally when sunlight is distorted as it passes through water droplets. This same phenomenon is accomplished when sunlight is distorted as it passes through a transparent prism.

I wanted to use a blend of human-made objects along with naturally occurring objects for this project.

The prism is human-made from silica, a naturally occurring element.

The supporting arm is wire that is human-made from copper, a naturally occurring element.

The colorful rock is naturally occuring and is composed primarily of silica.

Step 2: Selecting a Base for the Prism

The prism should have a sturdy base that supports the prism in such a way so that the prism is exposed to as much sunlight as possible.

The base can be made from anything such as wood, metal or ceramic, but I selected a colorful stone as I wanted to choose something from Nature that was made from natural forces over geologic time.

Step 3: Creating the Supporting Arm

I used a thick piece of copper wire, 5 mm in diameter, to create a Y-shaped arm to support and secure one end of the prism.

To make the Y use a hacksaw to make a cut, lengthwise, into the copper wire as seen in Photo 1. The length or depth of the cut is equal to the length of the prism face (Photo 2).

The next step is to carefully spread open the arms of the Y so that the prism will rest securely within the Y.

Use a thin piece of metal such as a saw blade (Photo 3) to carefully bend the copper. The saw blade supports the entire length of the copper arm during bending.

Bend the arms apart a little at a time, alternating from one arm to the next to ensure that the arms are symmetrical.

As seen in Photo 4, place the copper Y next to the prism to ensure that the widening of the copper arms is sufficient to hold the prism.

Step 4: Bending the Supporting Arms to Support the Prism

For this step it is best to show the final photo first to get a sense of what we are trying to do in the first place. Photo 1 and 7 show the glass prism resting in place with one end on the top of the stone and the other end nestled within the copper Y.

Start, as seen in Photo 2 by bending the copper Y so that the Y is level with the top of the stone. Bend the rest of the wire loosely around the base of the stone.

Now work to further bend the wire to conform to the shape of the stone as seen in Photos 3 and 4. As seen in Photo 5, cut the copper wire where it meets the rest of the wire at the base.

The completed copper wire supporting arm and base is seen in Photo 6.

Step 5: Silicone Supports

As seen in Photo 1, place a bead of clear silicone caulking on top of the stone in the place where the prism will rest on the stone.

Place a thin layer of clear silicone caulking on the inner surfaces of the copper Y (Photo 2). The silicone will create a grippy surface where the prism rests on the stone and copper Y. The silicone will help keep the prism in place and provide a protective cushion that will help protect the prism against chipping and scratching of the glass edges.

Use a sharp knife to cut a V-shaped groove in the caulking where the prism will rest on the stone as seen in Photo 3.

Step 6: Prism Placement

As seen in the photo, the final step is to place the prism and base in a sunny window and enjoy the rainbow colors indoors!

Step 7: Using the Prism to Track the Seasonal Movements of the Sun

Once you have your prism in place, you will notice that the beautiful rainbow colors travel in your room as the sun moves across the sky.

You can use the rainbow colors as a way to chart the sun's movement over time and with repeated observations, be able to mark and predict the arrival of either the winter or summer solstice.

To do this, find a window in your home that has good exposure to either the sunrise or sunset. You will also want to ensure that window sill is in a disturbance-free area where the prism can remain in place once it is set up.
So find a place where the family cat, dog, ferret, or python will not jar the prism.

Adjust the prism orientation by rotating or otherwise moving it so that the rainbow colors are displayed on the wall.

Once you are set up, note the location on the wall of the rainbow colors exactly as the sun is rising or setting. On the day of either solstice, depending on your window location, note the location of the colors at sunrise or sunset and mark by placing something such as a picture on the wall.

The following year you will know the solstice has arrived when the rainbow colors get closer and closer to the picture with each passing day. Finally on the solstice, the rainbow colors will "touch" the picture on the wall, as demonstrated in Photos 1-4.

You will notice with repeat observations that the rainbow colors will not travel any farther once the solstice is reached but instead the rainbow colors will slowly retreat in the opposite direction with each passing day.

Cultures throughout time have noted the position of the sun along the horizon as a way to keep track of the changing seasons. With all of our sophisticated instruments we really don't need to make our own observations but it is still fun to do so and helps keep us more in tune with our amazing world.

Step 8: Final Thoughts

Having a prism indoors allows for the creation of beautiful rainbow colors inside.

The prism is also a great educational tool and can be used as a springboard into explorations on subjects such as physics, optics, time, seasons, geometry, primary and secondary colors...and more.

Every home or office should have a prism in the window!

About This Instructable

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Bio: Lifelong interest in making and learning new things.
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