Activities Sun Burns
If you ever wanted proof of the power of the Sun, these next two activities are for you. By gathering the Sun’s energy that falls over a just a few inches of Earth’s surface and focusing it with a magnifying glass, you can create a point of light-heat that is hot enough to light a fire with paper and even burn wood. The temperature at which something will burn is called the flash point. The flash point for paper is 451°F (233°C) and for wood is 572°F (300°C).
Activity: Writing with Sunlight
When writing with sunlight, you’ll see how quickly the sun’s energy burns a piece of wood, and use it to create a nameplate or sign. Then you can ponder how else to put the Sun’s energy to use.
!Safety First! • Do this activity only with adult supervision. • Wear safety glasses and work carefully when sawing wood. When using the magnifying glass, don’t point the light any- where but at the exact spot where you need to focus it for your activity. The magnifying glass focuses the Sun’s power- ful radiation to a tiny point that is extremely hot and bright. Use that point of sunlight with the same safety measures you would use when handling a lighted match.
• Wear sunscreen that blocks UVA and UVB rays (SPF 30 minimum). • Wear sunglasses when looking at the focused point of sunlight. Use sunglasses that protect your eyes from 100 percent of the Sun’s harmful ultraviolet rays, including UVA and UVB. Just to be safe, work on your Writing with Sunlight project for only short periods of 10 to 15 minutes per day, to give your eyes a long rest from looking at the bright light. If you do not wear sunglasses while doing this activity, or even while looking over the shoulder of someone else doing it, you can burn your eyes’ retinas.
Materials: • UVA and UVB sunscreen (SPF 30 minimum) • Flat piece of softwood such as white pine (a piece that is 1/2 inch [1.25 cm] thick by 4 inches [10 cm] wide will do); be sure it’s long enough to fit the lettering you plan to use.
• Safety goggles • Small handsaw • Sandpaper (medium grit, #80) • Pencil • Sunglasses (100% UVA & UVB protective) • Handheld magnifying glass • Eraser
Do the Deed All you need is a little patience and a steady hand to write with sunlight. Keep the point of the beam as small as possible, and use it like a hot pencil. 1 Decide what you want the sign to say. Perhaps you want to make a sign with your name or the name of a friend, a fam- ily member, or a pet. You could create a sign to hang on the door of your room. Or how about making a sign that says “Catch the Wind” or “Harness the Sun”?
2. Gather a piece of wood on which you want to make the sign. Any kind of wood will work, but softwoods, like white pine, are lightweight and easy to cut, sand, and burn. If you don’t have a piece lying around the workshop in your house, try going to a hardware store or lumberyard and asking if they have a short piece of scrap wood that they’ll sell or give to you.
3. Put on your safety glasses, and use the saw to cut the wood into the size and shape you want, being certain to allow enough room for some lettering. A single name would easily fit onto a piece that’s about 12 inches (30 cm) long.
4. Sand the edges smooth so that the sign will look finished and you won’t get splinters when handling the wood. Just rub the sandpaper over any rough edges until smooth.
5. Lightly write the lettering onto the sign in pencil, along with any simple designs that you want to go with it. Use simple block letters that are only a few inches high, and space them as you normally would when writing on paper.
6. Take the board outside on the next sunny day. Put sunglasses on to protect your eyes from the bright light. (See the !Safety First! message about sunglasses at the beginning of this activity.)
7. Use the magnifying glass to focus the sunbeam onto the first letter of your sign until it starts to smoke and turn black. 8. Gradually move the beam along the lines of the lettering and designs, allowing the light to linger just long enough to create a black line where the Sun is burning into the wood. You are writing with sunlight! 9. Erase any leftover pencil marks.
GREEN TEACHER 93 Page 41
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