Hands-on science (no lab required).

Check out these two hands-on experiments after you've read "Could You Survive an Avalance?" (p. 10) and "Deep Seas, Dark Worlds" (p. 14). They're fun and foolproof!

LOOK OUT BELOW!

As you discovered in "Could You Survive an Avalanche?" some mountains are prone to snowslides. Discover how friction and a mountain's slope can trigger an avalanche.

YOU NEED:

1 sheet of newspaper ** three pieces of sturdy cardboard, 22 cm (8 1/2 in.) by 28 cm (11 in.) ** tape ** 1 sheet of waxed paper, 22 cm by 28 cm ** glue ** pencil ** 1 piece of felt, 22 cm by 28 cm ** 10 small pebbles ** 1 box of sugar ** 1 bag of flour ** 1 box of mashed-potato flakes ** protractor 

TO DO:

1. Cover the floor with a sheet of newspaper.

2. Use tape to cover one piece of cardboard with waxed paper. This surface represents an ice-covered mountain.

3. Create four layers of "snow" on top of the waxed paper. Cover the entire board with a 2-mm layer of sugar. This represents a light snowfall. Next, add a 5-mm layer of flour: Pack it down to represent a heavy snowfall. For the third layer, cover the board with dry mashed-potato flakes. This represents another light snowfall. Finally, add a 5-mm layer of flour. This represents a final, heavy layer of snow.

4. Have a partner line up the protractor with the edge of the cardboard to record the incline at which the snowpack begins to slide.

5. Slowly tilt the board until the layers collapse and slide. Record the angle at which the layers slid.

6. Cover the second piece of cardboard with felt. This surface represents a grassy mountain. Repeat steps 3-5.

7. Randomly glue the small pebbles onto the third piece of cardboard. This surface represents a rocky mountain. Repeat steps 3-5 once more.

CONCLUSIONS:

Which surface had the lowest angle of incline before the layers slid? How might the surface of a mountain affect whether it is avalanche-prone? Would wetting the layers affect your results? Try it!

HDT SPOT

Scientists explore deep-sea vents using a submersible vessel. But the vents can be two miles under the surface of the water: How could testing water samples help researchers determine where to lower the submersible?

YOU NEED:

4 cups of water * ** vinegar * ** thermometers ** blue litmus paper (* Teachers: See teacher's edition for details.)

TO DO:

1. Your teacher will give you four mystery * cups of water.

2. Using a thermometer, determine the temperature of each cup of water Record your results.

3. Dip a piece of blue litmus paper into each cup. If the paper changed color from blue to red, the water is acidic. If it didn't change, the water is neutral. Record your results.

CONCLUSIONS:

Which water sample could have been taken from near a deep-sea vent? Explain.

DON'T STOP NOW:

Research: Are there other ways to test for acidity? How?

Teacher's preparation instructions

1. Label four cups "A," "B," "C," and "D."

2. Fill cup A halfway with ice-cold water. Add 10 drops of vinegar and stir.

3. Fin cup B halfway with warm water.

4. Fill cup C halfway with ice-cold water.

5. Fill cup D halfway with warm water. Add 10 drops of vinegar and stir. (This warm, acidic water will represent a water sample taken from a deep-sea vent.)