Today, you’ll dive into an electrifying experiment, exploring the very phenomenon that helped Einstein unlock the secrets of the universe—and win a Nobel Prize! Light is made up of tiny particles called photons, but they are so small that we can’t see them with our eyes. Instead, we study how photons interact with different materials to understand how they work. In this experiment, you'll use the supplied sensor board to explore how the color of light changes the way it interacts with matter and come up with ideas to explain what you observe.
Created by Anthony Ledoux from Noun Project
Student Guide
Photon frenzy
Exploring the quantum side of light
What is a photon? How does the quantization of light affect the way light interacts with matter?
- LED Sensor Board
- CR2032 Battery
- LED
- 2x Jumper Wires
- 2 Flashlights (if your budget allows, buy more for each group)
- 1 Blue filter (if your budget allows, buy more for each group)
- 1 Yellow filter (if your budget allows, buy more for each group)
- Binder clips
Intro
Objectives
By the end of this lesson, you will be able to:
- Understand that light is quantized
- Understand what property of light is related to its energy
- Observe how light’s color can impact how it interacts with matter
You can create your own objectives too. After reading the introduction, what is your essential question or objective for this activity?
Before the experiment
Collect your materials from your teacher. This will include:
- 1x Sensor Board
- 1x CR2302 Battery
- 1x LED
- 2x Jumper Wires
Assemble the sensor board (Pay special attention to make sure you put the parts in the right way!)
- Put the battery into the holder on the back of the sensor board (the positive (+) side should face away from the board)
- Connect both wires to the connector on the bottom right of the front of the board.
- Connect the LED leads into the wires (the longer LED lead should be inserted into the” LED +” wire, the shorter LED lead should be inserted into the “LED -” wire).
Shine the flashlight onto the sensor LED on the sensor board to check that everything works. The LED on the wires should light up!
If the LED does not light up, double-check all components, correct the reversed components, and try again. If it still doesn’t work, ask your teacher for help.
During the experiment
- Preliminary data
Shine the flashlight onto the sensor LED. Observe and record what happens with the indicator LED.
- Make a hypothesis
What do you think will happen when you shine a blue light on the sensor LED? What about a yellow light? Write down your hypotheses.
- Test your hypothesis
Take turns with other groups using the flashlight station.
Hold the binder clip and put the blue filter in front of the flashlight, and look at the light. Do not shine it at the sensor board yet. Observe and record how the light changes. Note changes in color, brightness, etc.
Hold the binder clip and put the yellow filter in front of the flashlight. Do not shine it at the sensor board yet. Observe and record how the light changes. Note changes in color, brightness, etc.
Test your hypotheses by shining each color light on the sensor LED.
- Record what happens with each color.
- Pay attention to how this is different from the white light (no filter) and from each other.
Conclusion
Did your experiment prove or disprove your hypothesis? Either is okay; that is why we perform experiments. In fact, we sometimes learn more when our hypotheses are not correct because that means we have encountered something new!
Recall from the videos that light can be described as both a wave and a quantized particle.
- In this exploration, describe a time when light behaved as a wave.
- In this exploration, describe a time when light behaved as a particle.
We want to see if we can use the quantization of light to explain our experimental results. Remember: Quantization is when a system is forced to take on discrete (defined, definite) values, such as light behaving as particles called photons.
- Based on your experiment, what happens when a blue photon hits an electron in the LED?
- What about a yellow photon?
As an analogy, imagine the electron as a ball sitting in a valley and the photon hitting it as you giving it a kick. How would the strength of your kick affect what happens to the ball?
- Based on this analogy, can you think of a property of the blue and yellow photons which might cause them to interact with electrons differently?
Watch the conclusion video. You may update your previous explanation if this video gives you any new ideas.
Was your personal essential question answered? If so, what is the answer? If not, what additional information would you need to answer it?