How Does a Spotlight Work

Spotlights Are Electric

In their most basic form, spotlights are basic electrical circuits. A power source–which may, depending on the model of the spotlight, be either alternating or direct current—connects through a switch to a high intensity light bulb. When the switch is moved into the “On” position, a mechanism inside the switch completes the electrical circuit and allows current to flow from the power source, through the lamp, and back to the power ground path. A filament inside the bulb resists the flow of electricity and, as the electricity forces its way through, begins to glow. In some very high efficiency spotlights, the electrical current feeds a small circuit board that, in turn, illuminates a collection of high intensity light emitting diodes (LED) to produce light.

Spotlights Are Reflective

Although the flow of electricity illuminates a bulb inside the spotlight, the bulb alone is rarely sufficient to produce the large amounts of light for which spotlights are renowned. To amplify the light produced by the bulb, the concave area around the bulb is coated in highly reflective, angled material. The angles within the material catch and reflect the light from the bulb, amplifying its effect. This reflective area, which is usually comprised of aluminum-coated plastic, also serves to redirect the light into a steady beam, augmenting the function of the lens. Depending on the size of the spotlight and reflectivity of the coated area, a single bulb or small collection of LEDs can be amplified to 10,000 or more lumens (125,700 candle power).

Spotlights Use Lenses

While the bulb and reflective area of the spotlight produce ample amounts of light, the natural tendency of light beams is to scatter into a broad, unfocused area. Because scattered light waves would create an ineffective spotlight, manufacturers usually cover the bulb and reflective area with a special plastic or glass lens. Much like the lens of a camera or eyeglasses, the lens on a spotlight directs light from the source into a single, focused path. Depending on the make and model of the spotlight, the lens may be adjustable, allowing the user to switch from a dimmer light that covers a very large area to a very bright, focused light that is concentrated on a small surface.

How to Make Baby Hammock

Instructions
Making the Hammock Body

1,Fold 2 inches down on all sides of the fabric and sew to make an even hem. Thread all of the fabric through your steel ring, overlap the ends of the fabric by a good 3 inches and sew together.

2,Fold the fabric in half, and then holding the ring high, figure out the width of the bottom of your hammock. Measure that length, mark it on both sides, and sew two seams on each side. The baby’s mattress will fit in between these double seams. It should be between 12 and 20 inches wide.

3,Take your yard of fabric or use a pillowcase and decide how wide and long you want your baby mattress to be. If the base for the mattress you sewed into the hammock material is 12 inches wide, your mattress should be, too. The length is up to you, but should be at least 30 inches long. Once you have created a slip cover for this small mattress, fill it with foam or an old thin pillow, then quilt it.

4,Take your wooden dowel and figure out how low you want the hammock to hang. Measure about 12 to 14 inches from the top centered ring, more or less according to the distance you want between the dowel and the baby, and sew on some ribbon, string, or some kind of tie, 12 to 14 inches down from the ring on each side to attach the hammock to the wooden dowel.

5,Tie the hammock onto the dowel very tightly. Make sure it is well-attached and that there is no chance for the knots to come undone.

Installing Your Baby Hammock

6,Drill the hook into the ceiling. Do this right so that the ring can safely support the weight of the hammock. Attach the spring to the hook.

7,Decide how low you want your hammock to hang and attach a length of chain to the spring with a carabiner or quick link.

8,Attach the length of chain to the original ring at the top of your baby  wooden hammock with a carabiner or quick link.

How to Make Baby Hammock

Instructions
Making the Hammock Body

1,Fold 2 inches down on all sides of the fabric and sew to make an even hem. Thread all of the fabric through your steel ring, overlap the ends of the fabric by a good 3 inches and sew together.

2,Fold the fabric in half, and then holding the ring high, figure out the width of the bottom of your hammock. Measure that length, mark it on both sides, and sew two seams on each side. The baby’s mattress will fit in between these double seams. It should be between 12 and 20 inches wide.

3,Take your yard of fabric or use a pillowcase and decide how wide and long you want your baby mattress to be. If the base for the mattress you sewed into the hammock material is 12 inches wide, your mattress should be, too. The length is up to you, but should be at least 30 inches long. Once you have created a slip cover for this small mattress, fill it with foam or an old thin pillow, then quilt it.

4,Take your wooden dowel and figure out how low you want the hammock to hang. Measure about 12 to 14 inches from the top centered ring, more or less according to the distance you want between the dowel and the baby, and sew on some ribbon, string, or some kind of tie, 12 to 14 inches down from the ring on each side to attach the hammock to the wooden dowel.

5,Tie the hammock onto the dowel very tightly. Make sure it is well-attached and that there is no chance for the knots to come undone.

Installing Your Baby Hammock

6,Drill the hook into the ceiling. Do this right so that the ring can safely support the weight of the hammock. Attach the spring to the hook.

7,Decide how low you want your hammock to hang and attach a length of chain to the spring with a carabiner or quick link.

8,Attach the length of chain to the original ring at the top of your baby  wooden hammock with a carabiner or quick link.

How to Attach a Shade Sail to a Deck

1,Sketch the existing deck on a sheet of paper. Draw in the desired location for the sun shade sail. At least one vertex of the sail will attach to the roof structure, and the other ends of the sail will connect to railings or walls. If multiple sun shade sails are used, lay out the sails so that the ends of the individual sails share connections with neighboring sails. Multiple sails can create interesting and rich patterns.

2,Move all furniture from the deck. Lay out the square sun shade sail in their proper location on the deck, as drawn in the sketch. Mark the proposed location of the sail end connections on the roof, wall and railing surfaces.

3,Drill pilot holes for eye hooks and pad eye slots at the marked locations on the roof and wall. Eye bolts and rafter bolts are used at the roof structure. Connect these bolts using a friction connection, such as nuts and bolts with washers. Lag screws are a viable option, but they cannot carry the same load as friction connection bolts. Use pad eyes at walls and railings. If possible, fix pad eyes with friction connections.

4,Screw or bolt the rafter bolts, eye bolts and pad eyes to the surfaces around the deck. Do not overtighten lag screws because the wood can be weakened by slipping threads on the screw. Tighten bolts until the washers visibly deform the surface of the wood.

5,Attach the turnbuckles to the rafter bolts, eye bolts and pad eyes. Attach the ends of the shade sails to the turnbuckles. You may need to adjust the shade sails and their hardware to remove slack from the sail. After adjusting the triangle sun shade sail hardware, turn the turnbuckles until there are no ripples in the sail’s taut surface.

Homemade Party Tent

1,Connect four 10-foot PVC pipes together into a square using three-way PVC corner joints. The third flange should point up on all corners. Push the connections together tightly so that they do not fall apart.

2,Connect a 7-foot PVC pipe into the third flange of each corner to form the side posts, supported by the base created in Step 1.

3,Connect two 5-foot pieces of PVC pipe into the sides of a PVC T-joint to create 10-foot pipe with a flange in the middle. You may have to trim the ends slightly with a hacksaw to get 10 feet depending on the thickness of the T-joint.
Repeat this process to create a second pipe.

4,Build another square as outlined in Step 1, using two 10-foot pipes and the two pipes created in Step 3. The corner flanges should point down, while the side flanges should point up.

5,Insert a 3-foot pipe into each side flange.

6,Connect the 3-foot pipes with a 10-foot pipe, fitted with 90 degree angle elbow joints at both ends.

7,Attach the completed second square to the top of the side posts.

8,Drape a colorful, high-quality tarp over the top of the party tent canopyframe, letting it hang down evenly over the roof opening. Secure the tarp to the upper square with zip ties.

9,Cut additional tarp to form sides for the tent if desired. Attach them to the side posts with more zip ties. Leave one side open so people can get in and out.

10,Place a sandbag at each corner of the base square to hold the pop up party tent in place.

11,Decorate the tent with balloons, ribbons, strings of party lights or any other decoration that you want.

What Kind of Hammock Stand Is Most Secure？

Metal Hammock Stand
Metal hammock stands are popular because of their affordability and relatively light weight. Metal stands will work well on a flat surface such as a deck or a level lawn. Like other types of hammock stand, metal stands are stable on a flat surface, but not on a slope.

Wooden Hammock Stand
Like a metal stand, a wooden hammock stand is appropriate for flat surfaces such as patios, decks, and flat expanses of yard. A wooden stand generally is heavier than a metal stand. The weight makes a wooden stand seem more stable than a metal stand, but both types are perfectly adequate when set up properly.

Hammock Chair Stand
A hammock chair is a hammock intended for sitting instead of reclining. Like a metal or wooden hammock stand, a hammock chair stand is very stable and secure as long as it is placed on a level surface. The advantage of a hammock chair over a standard hammock is that the hammock chair stand takes up a smaller space, and so it may be easier to find a level place for it.

Making Your Stand Stable
If you have no level space in your yard for a stand, you can create one. Once you have the right spot for your hammock stand, it should be very stable and secure. For a slightly sloped yard, you can use railroad ties to make a retaining wall. Mark the area you plan to level, and place railroad ties along the length of the bottom of that plane. Drill into the railroad ties with a large drill, and hammer rebar into the hole made by the drill. Continue to hammer the rebar down into the ground until the top of the rebar is level with the top of the tie. Secure each tie to the ground by this method. Fill the slope with soil, and compact the soil with a tamper until it is firm. Use a level to determine whether the area is flat. If it’s still not level, nail a second course of railroad ties to the first, and add more soil. A seriously sloped yard will need a retaining wall installed to code standards by a professional contractor.

Tips for a More Secure Stand
Use the right type of hammock with the right type of stand. Not all stands will work with all types of hammocks. For example, a metal stand will usually only support a hammock that is spread with spreader bars. To find out what stands are appropriate for your hammock, read the manufacturer’s instructions.

How to Calculate Sun Shade Sail Forces?

1,Determine the area of the solar sun shade sail. A good place to start would be a 1-square kilometer (10^6 square meter) sail.

2,Determine the reflectivity of the sun shade sails. A black, completely absorbent triangle sun shade sail would have a reflectivity of 0 percent, while a perfect reflector would have a reflectivity of 100 percent. For this example, take a reflectivity of 90 percent.

3,Determine the solar flux at the distance from the sun at which your sun shade sail canopy will operate. The solar flux is the energy density of sunlight. For this example, put your sail at the same distance from the sun as the Earth. The energy density there is about 1350 joules per square meter per second. To calculate for other distances from the sun, multiply 1350 times (distanceEarth’s orbital radius)^2.

4,Calculate the momentum of the sunlight at your chosen distance from the sun. The momentum is the energy divided by the speed of light. For this example, the momentum would be 1350 3.0 x 10^8 = 4.5 x 10^-6 kg-ms.

5,Calculate the force over the whole square sun shade sail. The force is equal to the momentum change. If the light is absorbed, then the momentum change is equal to the momentum of the photons calculated in the previous step times the area of the sail. If the light is reflected straight back, then the momentum change is equal to twice the momentum in the previous step. For situations in between, the force is equal to the momentum of the light times (1 + reflectivity), where the reflectivity was determined in Step 2.

So the force = 4.5 x 10^-6 10^6 (1 + 0.9) = 8.55 Newtons.