Eisco Labs Advanced Newton's Cradle with Red Wood Base - 7.25" Tall, 4.3g Ni Plated Steel Balls, 7"x6" Base

This newton's cradle demonstrates the conservation of momentum on a 6" x 7" red wood base with it's 6.25" arms 4.375" away from one another. The 5" string length provides a pendulum length of 4.496" to the 4.3g nickel plated stainless steel balls each 0.876" in diameter. Overall, the unit weighs in at 1.65lbs and is a perfect gift anyone who is nerdy, into science, geeky, or just generally awesome. It also looks pretty good on anyone's desk. It comes disassembled, and while it's pretty easy to put together, you must very careful and delicate while assembling it. The strings can warp easily and will make the cradle out of alignment. Make sure you read the instructions though and wait to remove the Styrofoam until after the uprights are screwed into place. Putting it together incorrectly can lead to string warping which will ruin your lovely newton's cradle. Seriously, we would be really sad if you did that. You probably would be too.