Physics- Infrared Radiation and Investigating Infrared Radiation Flashcards
What is Infrared Radiation?
Infrared Radiation is a type of electromagnetic wave given off by all objects - the hotter the object, the more infrared radiation it gives off.
Infrared Radiation is also absorbed by all objects, regardless of their temperature.
However, different types of surface can absorb and emit infrared radiation at different rates.
Name an equipment used regarding Infrared Radiation:
Thermal Imaging Cameras can be used to show how much infrared radiation is given off by an object (compared to it’s surroundings) - the brighter the colour, the more is released.
What is a ‘perfect black body’?
A ‘perfect black body’ will absorb all radiation directed at it, and can also act as the best possible emitter; it cannot reflect any radiation.
How are surfaces that absorb and emit linked to eachother?
Surfaces that are good absorbers will also be good emitters - infrared radiation transfers more efficiently both ways on such surfaces.
How is Infrared Radiation linked to keeping the Earth warm?
Infrared Radiation is the only thermal energy transfer process that can take place in a vacuum, since no particles are required. This is how the Sun is able to heat the Earth.
As with any object, if Infrared Radiation is gained by the Earth at the same rate it is lost, the temperature of the Earth remains constant.
However, a number of factors, like the nature of the surface of a planet and the composition of the atmosphere may change this energy balance.
What is Global Cooling?
If Infrared Radiation is emitted from a planet at a greater rate than it is absorbed, the temperature of the planet will decrease. (Global Cooling)
What is Global Warming?
Global Warming refers to the long-term increase in the Earth’s average surface temperature due to human activities and natural processes. It’s when Infrared Radiation is absorbed at a greater rate than it is emitted, making the temperature of the Planet increase.
How is Global Warming caused?
This phenomenon is primarily caused by the Greenhouse effect- a natural process where the Earth’s atmosphere traps heat, keeping the planet warm enough for life. However as our carbon dioxide emissions increase, more infrared radiation becomes trapped by Greenhouse Gases, leading to MORE Global Warming and Climate Change, which refers to the long-term shifts in Earth’s average temperatures and weather patterns.
-The Burning of fossil fuels eg oil, coal release Greenhouse gases into the atmosphere
-Deforestation
-Industrial activities
Write the Method for Investigating Infrared Radiation, Emitters :
Emitters- METHOD
-Arrange three boiling tubes in a rack- one clear, one coated in matt black paint, and one coated in shiny silver paint
-Pour 20cm cubed boiling water into each tube, and record the initial temperature of the water in each tube using a thermometer
-Immediately start the timer. Record the temperature of the water in each tube at one-minute intervals for a total of 15 minutes, using a thermometer + stopwatch.
Write the context part of the Method (the first part), including the apparatus and variables for the emitter method:
Equipment:
-3 Test Tubes: Matt black, Shiny Silver, Clear
-Thermometer
-Stopwatch
-Kettle (Hot water)
Independent Variable- Type of Surface Used
Dependent Variable- Temperature of the water
Control Variable- Volume of the water, the time taken
Write the Method for Investigating Infrared Radiation, Absorbers:
Absorbers- METHOD
-Use the same three boiling tubes in the previous experiment; replace the water from the previous experiment with 20cm cubed of COLD water
-Place the boiling tubes in front of an infrared heater. Record the initial temperature of the water in each tube using a thermometer.
-Switch on the infrared heater, and immediately start the timer.
Record the temperature of the water in each tube at one - minute intervals for a total of 15 minutes, using a thermometer and stopwatch.
Write the context part of the Method (the first part), including the apparatus and variables for the absorber method:
Equipment:
-3 Test Tubes: Matt black, Shiny Silver, Clear
-Thermometer
-Stopwatch
-Kettle (Cold water)
-Infrared Heater
Independent Variable- Type of Surface Used
Dependent Variable- Temperature of the water
Control Variable- Volume of the water, the time taken
Write how to conduct your results (as part of the method):
Both experiments will have their own results table with 4 columns- one showing time (in minutes), and then one column for each of the boiling tubes, showing the temperature of the water.
For each experiment, you should plot a graph, showing temperature (y-axis) against time (x-axis). You will have one graph for the emitter experiment, and one graph for the absorber experiment.
Plot the data for each boiling tube on each graph, connecting the points with a smooth curve of best fit- you will have three curves on each graph (don’t forget to label them).
What is your brief conclusion of these experiments?
Looking at the data collected, the type of surface that was the best at emitting infrared radiation was the Matt Black due their ability to absorb all wavelengths of light and convert them into heat. The worst was the Shiny Silver.
The type of surface the best at absorbing the infrared radiation was the Matt Black and the worst was the Shiny Silver.
The reason why the Matt Black test tube also decreases in temperature overtime is because, its the best absorber so t is also the best emitter and so releases that energy.
The type of surface that was the best at reflecting infrared radiation was the Shiny Silver and the worst was the Matt Black. The Clear absorbs and emits, and reflects very little.
The best emitter will be the best….
The worst absorber will be the best…
absorber
reflector
