Uneven Heating Questions
- What causes Earth’s surface to heat up?
- What are some of the variables that cause uneven heating of Earth’s surface?
- What happens to the temperature of equal volumes of soil and water when they are place in the sunshine for 30 minutes?
- What will happen to these objects when I drop them into the water?
- Floats - less dense than water
- Sinks - denser than water
- Which objects are less dense than water?
- Which objects are denser than water?
- Is water denser or less dense than cork?
- Is a vial cap denser or less dense than a penny?
Cold Water Challenge
- Do you think the blue ice water is denser, less dense, or the same density as room-temperature water?
- Fill vial with room temperature water. Let stand 1 minute undisturbed.
- Use bulb pipette to take up bulbful of blue cold water.
- Gently squeeze bulb to release blue cold water on either the bottom or the surface of the vial of water. Use a steady slow squeeze.
- Observe the vial carefully to determine if the cold water floats or sinks.
- What happened to the cold blue water when it was placed in room-temperature water?
- Why do you think the blue water went down?
- Is the blue ice water denser, less dense, or the same density as room-temperature water?
- What do you think will happen if you warm up the bottom of the vial where the cold water is sitting?
Hot Water Investigation
- Carefully place the vial with blue water on the bottom into a plastic cup.
- Fill zip bag half full of hot water, using the syringe. Seal top of bag shut.
- Slowly lower bag of hot water into the cup with the vial.
- Closely observe the blue water carefully for 4 minutes.
- Make accurate illustrations of movement of cold blue water. Write captions under each illustration.
- What happened to the cold blue water in the vials after the hot water was placed beside it?
- Why do you think the blue water moved up?
- Why do you think warm water moves up?
- Why do you think the blue water started to sink after coming to the surface?
- What pattern did the blue water make after the hot water was added?
- Materials sink in water if they are denser than water.
- Materials float in water if they are less dense than water.
- A circular current in a fluid caused by uneven heating
- Is hot water denser or less dense than room-temperature water?
- Hot water is less dense than room-temperature water.
- Which is denser, hot water or cold water?
- Cold water is denser than hot water.
- What causes a convection current?
- Occurs when the bottom of a mass of fluid is heated. Warm water rises, cools, and then descends, creating a circular flow.
- Homework: Read Wind! Pg. 202-207 and answer questions.
- Explain how convection currents are produced in the air.
- Explain what causes wind.
- Describe what happens to air molecules when air is heated.
- What is the source of energy that causes the wind to blow?