Toy designed for older audiences, such as teenagers or adults, demonstrate advanced concepts. Newton's cradle, a desk toy designed by Simon Prebble, demonstrates the conservation of momentum and energy. Not all toys are appropriate for all ages of children. Even some toys which are marketed for a specific age range can even harm the development of children in that range. "Age compression" is a toy industry term that describes the modern trend of children moving through play stages faster than they did in the past. Children have a desire to progress to more complex toys at a faster pace, girls in
Tests of relativistic energy and momentum However, they made many improvements, including the employment of a Geiger counter. The accuracy of the experiment by which relativity was confirmed was within 1%. An even more precise electron deflection test was conducted by Meyer "et al." (1963). They tested electrons traveling at velocities from 0.987 to 0.99c, which were deflected in a static homogenous magnetic field by which "p" was measured, and a static cylindrical electric field by which formula_13 was measured. They confirmed relativity with an upper limit for deviations of ∼0.00037. Also measurements of the charge-to-mass ratio and thus momentum of protons have been conducted. Grove