Why water matters for life: cohesion, adhesion, heat and ice

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Use this

   Side view of a water drop on a plate, not to scale. The drop is a round dome. Water molecule beads inside the dome are joined to neighbors by dashed hydrogen bonds.

2. 1.

   Kira sets a drop of water on a smooth plate. It stays in a round dome instead of spreading flat. What holds the dome together?

   • Adhesion, from water molecules sticking to the plate
   • Cohesion, from covalent bonds between water molecules
   • Cohesion, since nonpolar molecules clump together
   • Cohesion, from hydrogen bonds between water molecules
3. 2.

   not to scale. A water strider rests on Milo's school pond without sinking. What explains why the water surface holds it up?

   • Surface tension, from hydrogen bonds between surface molecules
   • Surface tension, since nonpolar water bunches at the top
   • Adhesion, from water sticking to the strider's legs
   • Surface tension, from covalent bonds inside each water molecule
5. 3.

   Noah's class heated water and sand under one lamp. Which warmed faster, and what does that say about its specific heat?

   • Sand; it has the lower specific heat
   • Water; it has the lower specific heat
   • Sand; it has the higher specific heat
   • Water; it has the higher specific heat
6. 4.

   By minute 6, the sand's temperature had risen how many times as much as the water's, Pia?

   Use the picture in question 3.

   • 12 times as much
   • about 1.5 times as much
   • one fifth as much
   • 5 times as much
7. 5.

   model data, two identical dishes of warm water in the same breeze. Ren and a teacher set out two identical dishes of warm water in a breeze, one open and one covered. Which statement fits the data?

   • Both dishes cooled the same amount, since both started at 40 °C
   • The open dish cooled more, because evaporation took heat from the water
   • The open dish cooled more, because evaporation gave heat to the water around it
   • The covered dish cooled more, because the cover let heat escape
8. 6.

   model data. Tala gives 500 calories to 100 g of water and 500 calories to 100 g of sand. The water warms 5 °C. How much does the sand warm?

   • 25 °C
   • 1 °C
   • 5 °C
   • 100 °C
9. 7.

   5 g of the water in a runner's sweat evaporates. Evaporating 1 g of water takes 586 calories. What happens to the skin, Zee?

   • 591 calories leave the skin; the skin cools
   • 2,930 calories leave the skin; the skin cools
   • 2,930 calories enter the skin; the skin warms
   • 586 calories leave the skin; the skin cools
10. 8.

    Ari's teacher warms 80 g of water from 20 °C to 35 °C. Water needs 1 calorie per gram per °C. How much heat does the water take in?

    • 2,800 calories
    • 1,200 calories
    • 15 calories
    • 95 calories
11. 9.

    Side view of a pond on a cold night, not to scale. A pond begins to freeze on a cold night near Bo's home. Where does the ice form, and what does it do?

    • At the bottom; the deep water is the coldest
    • At the bottom; it is denser and sinks, leaving the top liquid
    • At the top; it floats and insulates the water below
    • At the top; it traps cold air against the water below
12. 10.

    not to scale. Jun looks at ice drawn as beads in an open lattice. When the ice melts, what happens to the links and the beads?

    • Hydrogen bonds loosen; the molecules slide closer together
    • Covalent bonds inside each molecule loosen; the molecules slide closer together
    • Hydrogen bonds tighten; the molecules move farther apart
    • Hydrogen bonds loosen; the molecules move farther apart