Activity 1.4.1

Hot, Cold and Currents

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

• food coloring
• ice cube tray (see Procedure #1--colored ice cube must be made in advance)
• large glass bowl or small aquarium tank
• hot tap water (43 C or 110 F)
• small bottle of ink
• salt
• test tube or cup
• Celsius or Fahrenheit thermometer
• safety goggles
• Activity 1.4.1 Student Worksheet
  
  

Procedure :

Part A

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




As you do each of the activities below, draw a sketch of exactly what is happening. Save your lab illustrations and explanations to include in your assessment portfolio.

1. Several hours before you need to begin the experiment, add at least 5 drops of food coloring to a small amount of water. Pour the colored water into an ice cube tray. You need to make 1 colored ice cube. Make sure the color is very dark.
   
2. Fill the glass bowl or aquarium tank to the rim with room temperature water. Let it stand for a minute or two so that the water will have a chance to settle before you start.
   
3. Place the colored ice cube very gently along the edge of the tank and observe for 1 minute or more. Record your observations.
   
   
   
   Do not disturb the tank until after the ice cube has completely melted. Observe again and record your observations.
   
   
   
4. What happened to the cold colored water? Try to explain why this happened. Think of a situation in nature that resembles the conditions in step 1.
   
   

Part B

Read through steps 1-2 and predict what will happen. Write it down.

1. Empty the fish bowl or aquarium and then refill it with fresh water at room temperature.
   
2. Run hot water until the temperature is at least 110 F (43 C). Fill a test tube or cup half full with this water. Add 5 to 7 drops of ink.Very gently pour this colored hot water into the tank. Observe for a minute or more. Record your observations.
   
   

What happened when you poured hot water into the tank? Try to explain why this happened.




Part C

Read through steps 1-2 and predict what will happen. Write it down.

1. Empty the container and then refill it with fresh water at room temperature.
   
2. Fill the test tube or cup half full of colored salt water. (Use 5-7 drops of ink to give it a dark color and 1/2 teaspoon of salt.)
   Very gently pour the colored salt water into the tank and observe. Record your observations.
   
   

Where in nature might you find conditions similar to those in this experiment?

Student Worksheet #1.4.1

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