Phase Changes in Everyday Life (Part 2)

What You'll Learn

The law of definite proportions states that a compound always contains the same elements in the same ratio by mass. Water is always 11.2% hydrogen and 88.8% oxygen.

Key Words

temperature
melting point

Materials Needed

salt
sugar
vinegar

Safety First

Dispose of materials properly after the experiment.
Handle glass items carefully to avoid breakage.
Do not mix unknown chemicals together.

Steps

Step 1 — Read

Look at the vocabulary words and write a definition for each in your own words.

Step 2 — Do

Create a density column: carefully layer honey, dish soap, water, vegetable oil, and rubbing alcohol in a tall glass. Drop small objects in to test where they float.

Step 3 — Observe

Compare the before and after states.

Step 4 — Record

Write your conclusion: did the results match your hypothesis? What would you change next time?

Check Your Understanding

Question 1

1 of 3

Which is a sign of a chemical change?