Report, Discuss, and Reflect
Due by Wednesday in the Discussion Forum
Post your report from Section I, Part E.
As an attachment to your post, include the temperature data you collected.
Due by Saturday in the Discussion Forum
Read and respond to your colleagues’ posts.
Read your colleagues’ reports, with any eye for any differences in your explanation of energy transfer. If you find discrepancies, use the evidence to try to reach a consensus.
The discussion question asks you to synthesize all the pieces of your assignment this week. Your responses to the question and to one another should draw upon and reference all your work and the session's resources.
After the discussion wraps up, look back at this week's goals, read What's the Big Idea?, and reflect on your work this week.
What's the Big Idea?
The big ideas in this session are
1. All objects radiate energy and the amount of energy that they radiate depends on their temperature. The higher the temperature of the object the more energy it radiates.
However, it is a little more complicated than just “higher temperature – more energy radiated”.
A radiating object emits photons with many different energies. When the temperature of the object is greater there are more photons with higher energies and fewer with lower energies.
Because objects emit photons at many different energies it is possible for a strong source of radiation at a low temperature to emit more total energy than a weak source of radiation at a high temperature. This is because the total energy carried by all the low energy photons from the low temperature object is greater than the total energy carried by the relatively smaller number of high energy photons.
It is also possible to explain this phenomenon using the wave model of light but that explanation requires a bit of mathematical subtlety.
2. Objects can be in thermal equilibrium under the action of radiation alone – if the rate of absorbing electromagnetic energy is equal to the rate at which electromagnetic energy is emitted.
Questions for Reflection
- What do you think is the most important thing you learned from this week's activities?
- What surprised you? Why?
- What questions are you left with?