HEAT EXPERIMENT#4

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 4
Date: xx/06/2018

Please spend five 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)

Are 'heat' and 'temperature' just different ways of saying the same thing?
How does heat move from one object to another?
How does heat move from the sun to the earth?
Draw a line right across the middle of the page (below your answers).

At the end of this session, write down new answers to the same three questions you answered earlier. Have you changed your mind about any of the answers you gave at the beginning of the session?

Why we focus on 'understanding the principles' rather than on 'learning the facts'

“Never memorize something that you can look up.” Albert Einstein - 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⁾

Matter is made up of atoms and molecules (groupings of atoms).
Energy causes the atoms and molecules to always be in motion - either bumping into each other or vibrating back and forth.
- The motion of atoms and molecules creates a form of energy called heat or thermal energy which is present in all matter. Even in the coldest voids of space, matter still has a very small but still measurable amount of heat energy.
- Energy can take on many forms and can change from one form to another.

In summary, put energy into a system and it heats up, take energy away and it cools.

Heat can be a chemical or physical phenomena but all chemical phenomena ultimately reduce to physical phenomena (physics)
Thermal energy itself can cause a substance to heat up, simply by increasing the speed of its molecules. For example, when we are cold, we can jump up and down to get warmer. If we stop moving, we cool down. ⁴⁾

The five important concepts about heat & temperature

Heat
Temperature - A measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale.
Conduction
Radiation
Convection

Heat Versus Temperature

Temperature is the degree of hotness (average speed of all molecules)
Heat is the quantity of hotness (total amount of heat energy for all molecules)
Compare the speed (temperature) versus impact (heat energy) of a table-tennis ball, tennis ball, basketball, cannon-ball - when each are traveling at exactly the same speed*

Video: Bill Nye -Complete Heat video for a rainy afternoon (22min)

IF UNABLE TO ACCESS YOUTUBE VIDEO, TRY:Viewpure

NOTE - FOR OUR EXPERIMENTS, WE PLAY SELECTED EXCERPTS ONLY - NOT THE FULL VIDE0:
Heat - Conduction
Debate - Featuring: Conrad Duction, Connie Vection & Ray Deation
Experiment - Conduction
Radiation - Infrared
Radiation - Fire Infrared
Radiation - Featuring Vivian Cupcake
Radiation - Featuring Disco Dance Night

QUESTION

What is the fastest way to cook brownies: Metal pan or glass pan?
Why?

Video. Eureka - Radiation & waves (4min)

IF UNABLE TO ACCESS YOUTUBE, TRY:Viewpure

Radiation experiment:

When any type of light is absorbed by an object, that object will be heated. The infrared light from an electric heater feels hot for two reasons: ⁵⁾

Use an infra-red light source to heat up an object
Use a mobile phone or infra-red camera to view a TVV remote control unit when pressing buttons
View an ice-block in infrared.
because surfaces seem black to infrared (IR) light, IR light is absorbed by objects.
because the infrared light (IR) is extremely bright light (although we do not see it).

A thermographic camera (also called an infrared camera or thermal imaging camera) is a device that forms an image using infrared radiation compared with a standard webcam/camera, which forms an image using visible light.

INFRARED RADIATION - LINK TO WIKI PAGE

Video. NASA - Radiation from the sun & the earth (3.5min)

IF UNABLE TO ACCESS YOUTUBE, TRY:Viewpure

2. Greenhouse Effect (Radiation)

An infra-red (IR) thermometer can be used to 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 cup.

The above can be measured using an IR thermometer.

QUESTIONS

What happens to the temperature inside the container - and why?
How could this experiment be extended/adapted to show a range of other heat-related effects?

Source - See Global Warming Experiment

Video. Roswell Flight-test Crew -Infrared Radiation (3.5min)

IF UNABLE TO ACCESS YOUTUBE, TRY:Viewpure

INVISIBLE LIGHT - LINK TO WIKI RADIATION EXPERIMENT ⁶⁾

BEFORE END OF SESSION (allow 10 minutes)

Learning Tasks That Elicit Evidence of Learning ⁷⁾

At the end of this session, write down new answers to the same three questions you answered earlier:

Are 'heat' and 'temperature' just different ways of saying the same thing?
How does heat move from one object to another?
How does heat move from the sun to the earth?

Have you changed your mind about any of the answers you gave at the beginning of the session?

Extension Activities

Video: Exploratorium (Bruce Yeany) - Heat & Radiation (4min)

IF UNABLE TO ACCESS YOUTUBE, TRY:Viewpure

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”.