Death Rate

Purpose of Lab: learn how to use the Scientific Method

to hypothesize about and determine the identity of unknown

substances

Experimental Data:

Table 1: Making Observations

Procedure Observation

1. torn paper

Vertical tear: almost straight, fiber is barely seen

Horizontal Tear: zigzag, fiber appeared

2. Appearance of rock salt crystals

Before crushing: colorless, semitransparency, chunky, a rough feeling, jagged

After crushing: cubic crystal, colorless, transparent

Wet: tiny sphere (particulates) like air bubbles

3 Appearance of sand

Dry: colorless (tiniest), light pink, white, gray with black dot (biggest)

Wet: The material remains unchanged

4. oil and water on plastic

Oil: When dropped, widely spread, flat from side view, clear, not reflect lights,

Water: When dropped, didn’t spread, oval from side view, clear, reflects lights

5. Making iodine in water: potassium iodide (KI), and sodium hypochlorite (bleach, NaClO). Both are clear before mixed together, but after mixed, it becomes yellowish brown.

6. Making iodine in oil: mineral oil, water, potassium iodide, and sodium hypochlorite. (iodine) Initially: looks like a sunny-side up. Oil (outside) and water (middle) are clear, iodine (inside) is yellowish brown

After 30 min.: oil is light purple, iodine is light yellowish brown

Drawing of what you see for step 6:

Please indicate the following on your drawing:

• where you think the water is,

• where you think the oil is,

• the