whats the best way to build a tetherball set for my backyard ?
411900
you can buy the ball and pole at a sporting good store.  then take an old tire and fill with concrete and set the pole. This way you can move it around.
338891
Try these:\n\nhttp://www.officialcornhole.com/baggo_cornholeproducts.html\n\nhttp://thefuntimesguide.com/movabletype/archives/2005/08/build_cornhole.html
182226
try this site \nhttp://lowpricedpoolsupply.com/above-ground-pools.html
614264
Go to Walmart....Buy 4 or 5 of those strofoam tubes that kids play with at pools and beaches. They are hollow on the inside. Cut down the middle lieght ways and place the tubs around the edges of you kayak. Turn kayak upside down on the roof and secure it.
715687
Start with three poles, tied together at the top with one end of a looooong rope.  Let the rest of the rope hang.  Form a tripod, then add other poles one at a time - continue to use the rope to tie them all together at the top. the last pole has the canvas attached - wrap it around. there ya go.
545902
Really easy project: http://www.hilaroad.com/camp/projects/clinometer/clinometer.html\n\nEasy trebuchet: http://hila.webcentre.ca/projects/trebuchet/index.htm\n\nEasy dome: http://www.hilaroad.com/camp/projects/dome/dome.html\n\nMeasure the diameter of the sun with geometry: http://www.hilaroad.com/camp/projects/pinhole_sun/sun_diameter.html\n\n\n\nA suspension bridge would be a nice project because the shape of the main cables that holds up the bridge is a mathematical curve called a "catenary."\n\nhttp://www.infovisual.info/05/028_en.html\nhttp://en.wikipedia.org/wiki/Suspension_bridges\nhttp://en.wikipedia.org/wiki/Catenary  (This article explains that the St. Louis Arch is an inverted catenary, and it even gives it's dimensions and the formula of the curve.  You could make a scale model.)\n\nAnd, it looks like I'm wrong  about suspension bridges.  Their main cables are parabolas, because of the weight of the deck.\n\nHere are some more projects you can check out:\n\nhttp://www.astrocappella.com/activities/cosr_lp.html (make the umbrella rigid by painting plaster on it)\n\nSolar reflectors would be good projects using parabolas: \nhttp://www.hilaroad.com/camp/projects/solar_energy/Hila_Solar_Energy.html\nhttp://www.cockeyed.com/incredible/parabola/parabola.html\nhttp://www.humboldt.edu/~ccat/solarcooking/parabolic/parabolic_solar_cooker_pg_3_html.htm\nhttp://peacecorps.mtu.edu/solarcookers.htm\nhttp://jc-solarhomes.com/fair/parabola20.htm
1153742
my backyard is good to use..
683251
I just helped my daughter with her science project. We made an electromagnet. Very easy to build and you can get buzzers, lights, and battery holders a your nearest hobby Lobby. you can also get toggle switches at the local hardware store. Mount it all on a nice piece of wood and your in business. by the way, my daughter took home first place!
305797
how about getting a bucket, a cups, and a dixie cup and then filling each with wet sand, turning it over to make a "sand castle" out of each.  you can show the kids the different sizes of each and how one is big, one is small and the other is in the middle (or for comparison words, you could do big-bigger-siggest).  you could then use these same size cups, scoop water into each and then pour it back into the pool.  each will make a different sized spalsh, again, big, medium, and small.  you could have the kids model make big medium and small pies of sand, or even provide them with wet sand to make the sand castle things themselves.
949238
u can  take rod shaped plastic pipe of different sizes & pingpong balls at sides. cover them with clay to give them shape of a bone, then use  thin elastic rubber ( which are used in rubber band, thin white in color) use many of them  as muscle fibre by attaching them to bone
488788
Tie a string to it ,at other end add a brick to it,leave it hanging for about 3 years
1047591
1. pay a workshop to do it for you\n2. put up an offer for a ready-drilled ball in eBay
391825
i believe you might find these 2 links useful, http://www.sunward1.com/woodkits.htm and http://www.redstoneprojects.com/trebuchetstore/build_a_catapult.html
493089
go to home depot,they have these grabber tools there the actually work pretty well as long as the item is not too heavy.I think they are around ten bucks.check in the inside garden center
609325
your concept should be under water, if you are planning it backyard, hang a higher clothesline across both your walls if you have, and you can hang lots of things, you can use all characters to float around. and put some decos on the ground too, if you plan it at night. it is much cooler, when you install lighting. buy blow bubbles too.
667305
Try visiting your local batting cages.  Set it for various speeds and hieghts.
967084
I would use a length of nichrome wire (see links below) stretched between a couple copper blocks. You could make some sort of pinch block out of the copper and connect a power supply to the copper. (or drill a hole through it with a set screw, tap a hole and us a pan head screw)  You will have to insulate the copper from the rest of the world so you don't short something out.  G-10 (a glass/epoxy resin) makes a good moderately high temperature insulator.  One of the contacts should be fixed and the other allowed to "float" and allow for changes in the length of the wire due to heating.  A spring could be used to provide tension or an air cylinder.  The power supply will depend on the length and diameter wire you choose.  If there is a problem with the electrical contacts heating up, you could run some cooling water through them.  Just drill a hole through it and 1/8 NPT pipe tape both ends.  You can plumb some water to it and it will keep the copper chilled.