Beach Ball Toss
To give my 3rd-grade students a sense of the Earth’s land-to-water ratio, we toss a beach ball that’s decorated as the globe. These are available inexpensively. As they catch the ball, they must report whether their hands land on earth or on water. I track their answers on the board. After every child has a turn, we tally up the results. This is usually successful: the ratio of hands on water vs. land matches fairly close with the Earth’s water-to-land ratio of 70% and 30%. As an extension, the student can call out the name of the continent on which their hand lands.