We do not necessarily recommend the following explanation for 5 th graders but here is the idea: An object floats when it displaces a volume of water that has a mass equal to the mass of the object.
Object permanence refers to understanding that objects continue to exist even when out of sight. Some people may misinterpret symptoms of ADHD as problems with object permanence, but research ...
For an astronomical object (e.g. a star or a galaxy) at a known distance from the Earth, the Hubble constant can be used to predict how fast it should be moving away from us. However, the true value ...