Newton's Cradle - Balance Balls 5 1/4" Newtons Cradle

Item is 5 1/4  inches tall.

Balance Balls are a classic desk toy. Also known as Newton’s Cradle, the clacking of the steel balls will keep you entertained throughout the day. Pull back one or more of the balls, release them and the same number of balls will swing up on the opposite side. This set of balance balls is fun for the office and makes a great desktop gift. 1. The apparatus. The apparatus usually consists of an odd number of identical steel balls each suspended by a bifilar suspension from a sturdy frame. The balls are carefully aligned along a horizontal line, just touching. When the ball on one end is pulled aside and allowed to swing as a pendulum, it hits the next ball. But the outcome is fascinating, the one ball on the far end is knocked away from the others with the same speed as the first ball had initially and all of the other balls remain nearly at rest. If you pull back two balls and let them strike the others, two balls are knocked from the other end, and all the other balls remain nearly at rest. Why does this happen? Why are these the only outcomes that occur? Why not others? We shall refer to this as the 'standard behavior' and the standard observed outcome, for the purposes of discussion. We are quite aware that this is an idealized outcome, and that the real apparatus doesn't quite achieve it, though it comes quite close. We are also aware that deviations from the ideal conditions (differences in mass, spherical vs. cylindrical masses, some balls touching, some not) can cause very interesting deviations from expected behavior and are severe tests for any model of system behavior. Some of these are discussed in the references at the end of this document. Why has this become a standard demonstration in physics courses? What important principle is it supposed to show? Usually it is "advertised" as a demonstration that momentum is conserved in collisions. Well, the outcome certainly does illustrate that, but so does every other mechanical interaction you might care to consider, whether it be elastic or inelastic. This particular apparatus, cleverly designed to be nearly elastic, is a special case, and the full generality of conservation of momentum is not demonstrated by it. Some books say that this demo shows that both energy and momentum are conserved in a collision. That's closer to the mark. But still, this apparatus is a special case: collisions between spherical balls of equal mass, size and composition. And those special conditions are responsible for the intriguing and special behavior we observe. Unfortunately this raises in the inquiring student mind all sorts of questions, such as "What if the balls were of different size, mass, shape or composition?" And that opens a whole can of worms that could lead one far astray and consume a lot of class time. It can easily get you into discussion of energy-dispersive systems and the importance of impedance matching. Seeing the demonstration raises a very sticky question: "How do the balls "know" that if you have N balls initially moving, that exactly N balls should swing out from the other end?" This is the feature of this apparatus that justifies the name "counting balls", for the system seems to "remember the number". All of these questions would be fine for an upper-level university physics course, but are hardly suitable for a freshman or high school course. Sometimes textbooks suggest a simpler version of the apparatus: marbles rolling on a grooved track. This presents even stickier problems, for the result depends on conservation of energy (including linear and rotational kinetic energy terms), conservation of momentum and conservation of angular momentum. Still worse, friction, rolling resistance, slipping on the track and momentum exchange with the track during the collision all affect the outcome.

General Information:

We are a family owned business that prides ourselves in selling fun and exciting science supplies, toys and gadgets for all ages.  We strive for %100 satisfaction and have included the information below to try and help answer all questions.  All of our products are new and in original, unopened packages/boxes directly from the manufacturer.  All of our merchandise is guaranteed within the guidelines listed below.  If you have any additional questions or concerns, please contact us Monday-Friday, 9am-4pm CST at 972.291.4223 and ask for Jeff or Teddie.

Satisfaction Guaranteed:

If you are not completely satisfied with your purchase, please return within 7 days from date of purchase in the original condition with all packaging intact.  If your return meets these requirements, we will be happy to exchange your item or refund your money.   All returns must be authorized.   Please email (gadgetscience@yahoo.com) or call (972.291.4223) to obtain your authorization number.  Return shipping is the responsibility of the customer. 

Return Policy for Defective Merchandise:

If you receive an item that is defective please contact us immediately (within 48 hours of receipt) to resolve the issue.  All returns for defective items must be authorized.   Please email (gadgetscience@yahoo.com) or call (972.291.4223) to obtain your authorization number.  After you receive an authorization number, please enclose a copy of your original order detail so that your refund is issued accurately and promptly.  Once we receive your return for defective item, we will issue a full refund for the item and shipping fees.

Domestic Shipping Policies (All 50 states and Puerto Rico):

We do offer combined shipping on multiple orders as long as the items are paid for with one payment at checkout.  The combined shipping fee will be based on the item with the largest shipping fee and then $1 will be added for each additional item purchased, with a max of $8.95 no matter how many items are purchased.   We ship via Fed Ex and USPS depending on weight, size and contents of the package.  We do our best to make sure all orders leave our warehouse within 2 business days.  However, in rare instances there may be delivery exceptions (when a package has been lost by the postal carrier or there is an address error).  In these cases, we will work 1-on-1 with you and the postal service to resolve the issue but we cannot file a claim until 30 days have passed, therefore, by purchasing an item from us, you agree to allow 30 days for your package to arrive. 

APO/AE:

Please email gadgetscience@yahoo.com to obtain shipping quote.  Shipping costs are determined by weight of the products.

International Shipping Policies:

We do offer combined shipping on multiple orders as long as the items are paid for with one payment at checkout.  The combined shipping fee will be based on the item with the largest shipping fee and then an additional amount will be calculated in the checkout processes based on the content, size and weight of the additional item/items.   We ship via USPS.  We do our best to make sure all orders leave our warehouse within 5 business days.  However, in rare instances there may be delivery inceptions (when a package has been lost by the postal carrier or there is an address error).   It is your responsibility to contact your post office and customs department to see if the package has arrived.  Many times a package is at the post office or being held at customs.  The timeframe for international shipping is not always reliable or accurate.  We have no control over what happens to a package once it leaves our warehouse.  Each country has different fees and policies.  You are responsible for all customs fees when your package arrives.   By purchasing an item from us, you agree to allow 45 days for your package to arrive.  If you still have not received your package after 45 days of purchase, we will work 1-on-1 with you and the postal service to resolve the issue. 

Canada Shipping Policy:

Items shipped to Canada do not fall under the Domestic or International shipping policies above.  The shipping charges for Canadian orders will be calculated in the checkout process. 

Texas Residents:

All Texas buyers will be charged  8.25% sales tax.

Insurance:

Insurance is optional for all of our items at an additional charge of $1.65.  If you pay for the optional insurance, Gadget Science will accept full responsibility for lost or damaged items during transit.  If you choose not to purchase insurance, you agree to accept full responsibility for lost or damaged items during transit. 

Every buyer gets a MyStoreRewards invitation for cash back