Activity 1.4.3

Mixing up the Water Column

Materials (for each group of 3/4 students):

• 2 identical wide-mouth jars (20 oz. size work well)
• 2 different food colorings in dropper-type squeeze bottles
• tap water
• 30 oz. cold water, prechilled in refrigerator
• index card slightly larger than the jar mouth
• safety goggles
• Activity 1.4.3 Student Worksheet
  

Procedure :

Part A

Read through steps 1-4 and predict what will happen. Write it down.

1. Half fill one of the jars with the hottest water the faucet will provide. Be careful not to scald yourself!
   
2. Half fill the other jar with the chilled water.
   
3. Allow the water in both jars to settle completely for a minute or so.
   
4. Take one of each of the fool-coloring squeeze bottles in each hand and carefully -- at the same time -- squeeze one drop of color into each jar.
   
   • Observe and record what happens.

Illustrate Part A below:















Part B

Read through steps 1-6 and predict what will happen. Write it down.

1. Completely fill one jar with hot tap water and the second jar with cold water from the refrigerator.
   
2. Add several drops of different colors of food coloring to each jar.
   
3. Place the index card over the mouth of the jar filled with hot water .
   
4. Holding the card firmly in place, quickly invert the jar of hot water and place it over the mouth of the jar filled with cold water.
   
5. While holding the jars in place, carefully remove the card and observe what happens.
   
   
   
   * Is this what you expected?
   
   
   
6. Now turn the jars over so that the hot water is on the bottom. What happens now? Record the results of the last two steps.
   
   

Illustrate Part B below:

Student Worksheet #1.4.3

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