BLUE PLANET Viewed from space Earth looks mostly blue with scattered brown patches That is because almost three quarters of Earth's surface is covered in water Less than 1 percent of this water is freshwater that we can drink and use The rest is mostly salt water in the oceans and some is frozen at the North and South Poles Can you see why Earth people call is the blue
A Water in the oceans makes up nearly 98 percent of all the water on Earth THINRABOUTI We cannot drink seawater because it has so much salt in it Instead While you read of quenching our thirst seawater this book think would dry us out The body tries about how rivers lakes and oceans to get rid of salt by making us produce more urine If the body are connected loses too much water it can no longer
E RIVERS CoMPAREAND CoNTRAST A river is a large area of moving freshwater Rivers flow toward oceans lakes or other rivers E Some are full of water all year round but rivers in dry countries may flow only at certain times of year Some rivers are only a few miles long Others such as the Nile in Africa and the Amazon in South America are so long they flow through many countries How do the rivers pictured in this book look alike How do they look different The Nile is 4 132 miles 6 650 km
ILL And an IRSCH The city of New York developed along the Hudson River Rivers are very important to people In the earliest times people made their homes alongside rivers so they had freshwater to drink to wash in and to cook with They also caught fish to eat from the river When people built ships they used the rivers to travel explore and buy and sell goods from farther
