This catapult design project is used to teach engineering skills to children.  It builds a slightly more complex torsion catapult than the previous methods, but requires just a few additional supplies and steps.  10 standard (4.5") craft sticks 1 jumbo (6") craft stick 1 drinking straw 1 6" length of wooden dowel, with a small enough diameter to fit through the straw 1 elastic band Glue gun and glue stick 1 milk jug lid or large bottle cap Ammunition! Ping pong balls and grapes both work well with this catapult project. These will hold the dowel/straw fulcrum that will support the throwing arm.  Add a dab of glue 1/2" from the top of a craft stick, and attach another stick to it at approximately a 30 degree angle.  Create a second upright that is the mirror image of the first. Place a dab of hot glue on each of the bottom legs of the first upright, and attach a craft stick connecting the two so that the vertical portion of the upright attaches to the end of the base.  Repeat this process with the second upright.  Then use hot glue to attach one additional craft stick to the front of each of the uprights. The base should now form a rectangle with one end open, and the two uprights sticking up parallel to one another. Cut a 2" length of straw and slide the dowel through it.  Use hot glue on to attach the dowel firmly to the wedge formed at top of the each upright. First loop an elastic band around the craft stick that connects the two uprights.  Then glue the large craft stick to the straw so that about 1/2" hangs below the straw. Finally, carefully attach the other end of the rubber band near the bottom of the large craft stick.  The throwing arm should now be able to rotate freely around the dowel on the straw, and the elastic band will put tension on the throwing arm as you pull it back. To create a strong bond with the throwing arm, use a pencil or other tool to press the elastic band firmly into the hot glue, and hold it  for a few seconds until the glue cools. Do not use your fingers or you will burn yourself! Your catapult is nearly ready to go, but a few more steps will make it sturdier and easier to use!  Attach the milk jug lid to the free end of the throwing arm with a dab of hot glue. Attach one additional craft stick horizontally to connect the slanted sides of the two uprights and provide additional stability. Add additional craft sticks to the bottom of the catapult that out as needed to keep the machine stable while firing. Load a ping pong ball or grape into the milk jug lid.  Pull back the throwing arm and let fly!

Summary: Gather your supplies. Build two uprights for the catapult. Build a base to hold the uprights. Add the fulcrum to the catapult. Build the throwing arm. Add the finishing touches. Fire your catapult!


A box bay window has two side panels that meet at 90 degree corners with the back panel. Stretch your tape measure across the back window panel from corner to corner at the panel's top, middle, and bottom, making sure to keep the tape level. Record the smallest measurement you get and subtract ⅜ of an inch (1 cm) for some extra “wiggle room.” “Face-fix” simply means that the blind brackets will be attached on the front face of the window frame, and will normally conceal both the frame and the glass. As with the back panel, take 3 horizontal measurements for each of the side window panels. Use the smallest measurement for each panel as your guide. Then, subtract ⅜ of an inch (1 cm) for your “wiggle room.” Before you buy or order blinds, contact the manufacturer or refer to the packaging to get the precise dimensions of the brackets. You need to know the depth in particular in order to get the proper width measurements for all of your blinds. For example, your brackets might be 2.5 inches (about 6.5 cm) deep. Your back blind can span from corner to corner (call this Option A), in which case you need to subtract the bracket depth (e.g., 2.5 inches) from both of the side panel measurements. Or, the side blinds can span from corner to frame edge (Option B), in which case you need to subtract the bracket depth twice (e.g., 5 inches) from the back panel measurement.  When pulled down, either the side blinds will slightly overlap the back blind at the corners (Option A), or the back blind will overlap the side blinds a bit (Option B). To avoid any overlap, you can subtract 5 inches (for example) from the back panel and 2.5 inches from each of the side panels. But your measurements and installation will need to be extra precise to limit gaps in blind coverage.

Summary: Measure the width of the back window from corner to corner. Measure both side panels from their corners to the edges of their frames. Confirm the depth of the roller blind brackets you'll be using. Choose which measurement(s) you want to subtract your bracket depth from.


If you have open programs when you force-quit your Mac, the programs will be forced to close as well, which can cause you to lose unsaved work. In some cases, force-quitting may even corrupt open programs or installers. To be as safe as possible, try to close any open programs before you force your Mac to shut down. Most Macs have a physical button with the "Power" {"smallUrl":"https:\/\/www.wikihow.com\/images\/5\/5d\/Windowspower.png","bigUrl":"\/images\/thumb\/5\/5d\/Windowspower.png\/30px-Windowspower.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of a Windows icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Public_domain\">Public Domain<\/a><br>\n<\/p><\/div>"} icon that you can press to turn off your Mac:   MacBook without Touch Bar — The "Power" key is in the top-right side of the keyboard.  MacBook with Touch Bar — The "Power" button is the Touch ID section on the far-right side of the Touch Bar.  iMac — You'll find the "Power" button behind the lower-left side of the iMac's screen. Once you've found the "Power" button, press down on it and don't release it for five seconds. At this point, your Mac should be off. If you see a prompt asking you to confirm that you want to turn off your Mac, you didn't hold down the key for long enough. This will allow your Mac to fully power down before you attempt to turn it back on.
Summary: Understand that force-quitting your Mac can cause problems. Find your Mac's "Power" button. Press and hold the "Power" button. Release the "Power" button after five seconds. Wait a minute before turning back on your Mac.