HEAT EXPERIMENT #5
Start and end each session with a visible thinking learning task - what I used to think and what I think now - to help implement the Five Formative Assessment Strategies to improve student learning.
Learning Tasks That Elicit Evidence of Learning 1)
Open your Science book/Journal and briefly write down the title, date:
Title: HEAT Experiment 5
Date: xx/06/2018
Please spend ten minutes to write down what you think about each of the statements below (you may use drawings/images or refer to other sources of information). For each question, explain why you think your answer is correct.
What do you think is most likely to have more heat - candle burning on an ice-cream birthday cake, or the ice-cream cake?
How does heat move along a metal ruler?
Can you tell how much heat energy something has by measuring how hot it is?
At the end of this session, you will have another chance to think about and write down your answers to the same three questions.
Why we focus on 'understanding the principles' rather than on 'learning the facts'
“We need less memorization - I never memorized the periodic table of the elements - I've never used it, and I'm a physicist! I can look it up” Michio Kaku - 2)
If your teaching/learning focuses on an understanding of the principles, you don't need to remember the facts - just look them up. No matter how many facts you remember, there is no guarantee that you will ever understand the principles that underly them.
All that you need to understand about the current scientific view about
heat is….
Everything in the universe is made up of matter and energy.
“The beauty of a living thing is not the atoms that go into it, but the way those atoms are put together” 3)
In summary, put energy into a system and it heats up, take energy away and it cools.
The only five things you need to understand about heat & temperature
Heat versus temperature
How heat energy can transfer
Video. Bill Nye - Heat (2min)
Video. Bill Nye - Conduction, Convection & Radiation (2min)
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1. Conduction experiment:
Image: How heat travels along a spoon
Arrange blobs of cold butter at equal intervals along the handle of a metal spoon/knife (or similar.
Place a small paper-clip upright in each blob of butter
Bend the 'scoop' end of the spoon at right angles to the handle
Heat the spoon by immersing the bent, scooped end of the spoon into hot water.
2 Convection Experiment
Video. Convection Currents 2 (2min)
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MATERIALS
Cup of iced water
Cup of hot water
Two cups of room temperature water
Food colouring (blue + red)
Two pipettes
Transparent water tank (fill with room temperature water)
This is a new experiment showing how heat moves from one place to another via convection.
HYPOTHESIS:
METHOD
Place a cup of iced water under the left hand side of the water tank
Place a cup of hot water under the left hand side of the water tank
Mix some red food colour into a small cup full of room temperature water
Mix some blue food colour into a small cup full of room temperature water
Fill one pipette with red food colouring drawn from room temperature coloured water
Fill one pipette with blue food colouring drawn from room temperature coloured water
Carefully squeeze blue colour into the bottom of the tank - The cold/left side of the tank and red into the hot/right-hand side
Slowly continue to fill pipettes and release more food colouring into the water tank
DISCUSSION
3. Infrared Radiation experiment
An infra-red (IR) thermometer can be used to help make some experiments more concrete.
Other types of energy that convert into thermal energy can be inferred from thermal signals. Hence, many invisible physical, chemical, and biological processes that absorb or release heat can be visualized, discovered, and investigated.
The following experiment can be successfully performed using a simple IR thermometer only.
An IR Trap (The Greenhouse Effect)
Shine a desk lamp (or invisible IR light source) through an inverted plastic take-away or similar container.
The light will be absorbed by the black paper inside.
The paper will radiate IR light, but the IR radiation emitted from the paper cannot penetrate through the transparent container.
As a result, heat is trapped inside the inverted container.
The above can be measured using an IR thermometer.
QUESTIONS
Source - See Global Warming Experiment
Video. Radiation Fog (2min)
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Radiation Fog forms when a layer of warm, wet air forms close to the ground and another layer of cooler, drier air forms on top of the warmer layer. When the ground begins to cool down, the water droplets in the warm, wet air begin to condense to form fog. This type of fog is called radiation fog.
Fog will form in one of the bottles – make a prediction based on the description of how fog forms on which bottle will produce a simulation of fog. Which one do you think will produce the fog?
MATERIALS
Estimated Experiment Time - One to two hours at most.
PROCEDURE
Empty the soda bottles and rinse them out thoroughly. Label each soda bottle, one with “Cold water” and the other with “Hot water.”
Fill the first soda bottle ¼ of the way full with cold water. Place an ice cube in the neck of the soda bottle so it is wedged in but does not pass all the way through the bottle. What happens? Record your findings in your journal.
Repeat step two with the second soda bottle, only this time, filling the bottle ¼ of the way full with hot water. Place the ice cube in the neck of this soda bottle and note what happens.
Note - This experiment is an accurate simulation of radiation fog.
OBSERVATION
Watch what happens with each soda bottle and remember to record your findings in your journal or logbook.
Fog will form in the bottle with the xxxx water, but it will not form in the bottle of xxxx water.
Why do you think that is? How does the description of how fog is formed relate to your findings?
What do you think would happen if you repeated this experiment with several soda bottles with different temperatures of water?
What do you think would happen if you used only warm water (not hot) or lukewarm (almost cool) water? Do you think more or less fog would form in the soda bottle?
How do the results of the experiment apply to real life situations?
Back to where we started
We started our study of HEAT on this page.
Here were some of our first questions:
Are some materials warmer or colder than others?
What is the difference between 'hot', 'cold' and 'heat'?
Does the temperature of something depend on it's size (a small versus a large ice block)?
How does heat move from one object to another?
Thinking about what you have seen over the last few weeks, do you think you have you changed any of your ideas about these questions?
BEFORE END OF SESSION (allow 10 minutes)
Learning Tasks That Elicit Evidence of Learning 5)
At the end of this session, write down new answers to the same three questions you answered earlier:
What do you think is most likely to have more heat - candle burning on an ice-cream birthday cake, or the ice-cream cake?
How does heat move along a metal ruler?
Can you tell how much heat energy something has by measuring how hot it is?
Extension Activities
REVISION - Does 'heat rise' and/or 'does hot air really rise'?
'Does hot air rise (due to heat)' or does 'cold air fall (due to gravity)'?
When you have two theories to explain the same thing, what can you do
To test a theory, design an experiment where each theory predicts a different outcome.
In the space station, there is plenty of air but almost no gravity.
If hot air rises, then it should also 'rise' in zero gravity. Does it?
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High above our planet in the realm of satellites and space stations, the familiar rules of Earth do not apply. The midday sky is as black as night. There is no up and no down. Dropped objects do not fall, and hot air does not rise.
6). In the absence of gravity, there is no buoyant force so no movement is possible physically but however hot air will start exchanging heat with the cooler air by means of conduction and radiation if they are in contact with each other and only by pure radiation if they are not in contact. ( no convection can takes place because of the absence of gravity)
7)
Video: Convection in zero gravity (2min)
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Video: Gravity - The curved fabric of space time (4min)
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Video: Relativity - The fabric of space time (2min)
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Video: Gravity - The fabric of space time (5min)
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</WRAP
Exploratorium Science Snacks
2. Convection experiment:
Video. Exploratorium - Convection (3.5min)
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Visualize the fluid motion of convection cells. This phenomenon occurs all around us but is usually unseen. For this activity, all you need is soapy water, a heat source, and some food coloring—the effect caused by the rising and sinking fluids is spectacular. Full instructions for doing this activity on your own are available at: http://www.exploratorium.edu/snacks/p….
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Video: Exploratorium (Bruce Yeany) - Heat & Radiation (4min)
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READ MORE...
The exposed filament from a 100-watt (or similar) incandescent light bulb is wired in series with a flashlight bulb and a battery. Blow on the filament and the flashlight bulb gets brighter (radiation).
When you blow on the exposed filament, you cool it off because the air current carries away a fair amount of heat energy (convection). As the temperature of the filament decreases, its electrical resistance (conduction) decreases as well. This is because the atoms making up the filament vibrate less at lower temperatures, making collisions between the atoms and the electrons moving through the filament less likely. With fewer collisions, the electrons move more freely through the filament—in other words, they encounter less resistance (increased conductivity).
Lowering the resistance of the exposed filament lowers the resistance of the complete circuit (or, increases the conductivity), allowing the flow of current in the circuit to increase. Since the flashlight bulb is part of the complete circuit, current through it also increases, making it glow more brightly.
When you screw in the flashlight bulb, its tiny filament heats and glows almost instantaneously, but it takes the large exposed filament a second or two to reach maximum temperature. For the short amount of time that the large exposed filament is relatively cool and has low resistance, the flashlight bulb glows very brightly; but once the exposed filament heats up and its resistance increases, the current in the complete circuit is reduced and the flashlight bulb dims.
When you turn on an incandescent lamp, the filament starts out at room temperature. While the filament is relatively cold it has a low resistance; it draws a large pulse of electric current at first, then settles down to a lower, constant current. The initial burst of current can be ten times greater than the constant current.
Sensitive Filament - Use your breath to see how temperature changes create a visible change in an electric circuit.
Charles's Law - Using a syringe to discover the relationship between the temperature and volume of a given amount of gas (air).
Concord 'InfraredTube' Concord InfraredTube provides resources that use affordable IR cameras to visualize invisible energy flows and transformations in easy-to-do science experiments… making thermal energy more readily “seen”.
Helio-centric versus Helical Motion Of Our Solar System (4min)
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References