Have you ever thought about how people entertained themselves before all the gadgets we have today? They had to be creative! If you’re feeling bored, why not try some fun experiments to explore light, one of the fastest things in the universe? Here are three cool experiments you can do with just your hands.
First, close one eye and look at something across the room, like a straight edge or a pattern. Hold your finger a few inches in front of your open eye. Focus on the distant object and let your eye relax until both your finger and the background are a bit blurry. Move your finger side to side and watch what happens. The light seems to bend around your finger! For some, it bends toward the finger, and for others, it bends away. Try it a few times to see the effect.
Close one eye again and look at something bright in the distance (but never look directly at the Sun!). Slowly bring your two fingers together in front of your eye. Just before they touch, they seem to merge into one. You can also try this with two objects on a sunny day; as their shadows get close, they appear to join together.
With one eye closed, bring two fingers close together near your eye and look through the small gap. Move your hand back and forth and watch for dark lines forming between your fingers. These lines can change as you move your hand.
So, what’s happening in these experiments? It all comes down to how light passes through lenses, like the ones in your eyes or a camera. When light hits an object, it spreads out and passes through a lens, bending toward a point called the focal point. Your eye changes the shape of its lens to focus, while a camera adjusts its lens position.
If the lens is out of focus, light rays don’t meet at the right spot, making the image blurry. When you put something like a finger between the object and the lens, it blocks some light rays, causing part of the image to disappear.
This leads to the shadow blister effect. The darkest part of a shadow, where light is completely blocked, is called the umbra. The lighter area around it, where only some light is blocked, is the penumbra. When two penumbras overlap, they can block enough light to create visible effects, making shadows look like they bulge.
The dark bands between your fingers might be due to diffraction, which is when light waves interfere with each other. However, diffraction usually needs a specific light source, which we don’t have here. Plus, different light wavelengths diffract differently, so white light should show colored bands, not just dark ones.
These experiments show how boredom can spark curiosity. Many scientists, like Einstein, found that letting their minds wander led to amazing discoveries. Einstein’s thought experiments helped him develop the theory of general relativity, which predicted gravitational lensing—where massive objects bend light from distant sources.
So, next time you’re bored, remember that it can lead to exciting discoveries. Stay curious and keep exploring!
Speaking of curiosity, thanks to Curiosity Stream for supporting PBS Digital Studios. Curiosity Stream is a streaming service with documentaries and nonfiction titles from top filmmakers. I’ve been watching “Dream the Future,” a series about what life might be like in 2050. It’s narrated by Sigourney Weaver and available on Curiosity Stream. You can get unlimited access, and the first 60 days are free if you sign up at curiositystream.com/smart with the promo code “smart.”
Use your understanding of how light bends to create an art project. Gather materials like colored cellophane, glass prisms, and mirrors. Arrange them to create a light display on a wall or paper. Observe how light bends and changes color as it passes through different materials. Take photos of your creations and share them with the class.
Work in groups to create a shadow play using a light source and cut-out figures. Experiment with the distance between the light source and the figures to see how it affects the size and clarity of the shadows. Perform your shadow play for the class and explain how light and shadows are used to create the effects.
Create a simple camera obscura using a cardboard box, aluminum foil, and a piece of white paper. Poke a small hole in the foil and place it over one end of the box. Point the box at a bright scene and observe the inverted image that appears on the paper inside. Discuss how this relates to the way your eyes and cameras work.
Use a glass prism to explore how white light can be split into different colors. Shine a flashlight through the prism and observe the spectrum of colors that appears. Try to identify the colors and discuss why this happens. Relate this to the concept of diffraction and how light waves interact.
Create a maze using mirrors and a laser pointer. The goal is to direct the laser beam from the start to the finish by strategically placing mirrors. Work in teams to design the most efficient path and test different configurations. Discuss how light reflection and angles play a role in solving the maze.
Here’s a sanitized version of the provided YouTube transcript:
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Thanks to Curiosity Stream for supporting PBS Digital Studios!
Hey everyone, Joe here. Have you ever wondered what people did before we had all these devices to keep us entertained? Back in the day, people had to be more creative. Next time you feel like life is moving too slowly, why not put those idle hands to use and explore the fastest thing in the universe? Here are three experiments that will show you how to bend light using just your own two hands.
**Experiment 1:** Close one eye and look at something across the room, preferably with a nice straight edge or an interesting pattern. Next, place your finger a few inches in front of your eye. Focus on the object in the distance and let your eye relax until both your finger and the background are slightly out of focus. When you move your finger side to side, notice what happens—the light seems to bend around your finger. For some people, it may appear to bend toward the finger, while for others, it may bend away. With a few tries, you should be able to do this easily.
**Experiment 2:** Close one eye and look at something bright in the distance (but not the Sun—never look directly at the Sun!). With one eye shut, slowly bring your two fingers together just in front of your eye. Just before they touch, they seem to reach out and merge into one another. You can also try this with two objects on a sunny day; right before their shadows touch, they seem to push out and join.
**Experiment 3:** Close one eye again and slowly bring two fingers together near your eye while watching the light through the small gap between them. You should see a series of dark lines forming as you move your hand back and forth. The pattern of these dark lines can change.
So, how do these light-bending experiments work? Let’s break it down. The key lies in how light passes through a lens, whether in your eye or in a camera. When light reflects off an object, it spreads out and passes through the lens, bending toward a different point behind it. The spot where the light converges is called the focal point. Your eye physically changes the shape of its lens, while a camera adjusts its position to focus images.
When the lens is out of focus, light rays from a fixed point don’t converge exactly on the sensor or retina, resulting in a blurred image. If we insert something between the object and the lens, like a finger, we block some of those rays, causing part of the image to disappear.
This leads us to the shadow blister effect. The darkest part of a shadow, where an object completely blocks the light source, is called the umbra. The hazy area around it, where only part of the light is blocked, is called the penumbra. When two penumbras overlap, they can block enough light to create visible effects, making the shadows appear to bulge.
As for the dark bands seen between our fingers, many explanations suggest this is a demonstration of diffraction, which involves the interference of light waves. However, there are reasons to question this. For diffraction to occur, we typically need a coherent light source, which we don’t have here. Additionally, different wavelengths of light diffract differently, so white light should produce colored bands, not just dark ones.
I encourage you to try these experiments yourself and share your thoughts on what’s happening. I’d especially love to hear from anyone with expertise in optics or neuroscience. Everyone is welcome to explore this further!
Being bored can actually inspire curiosity. Many great scientists, including Einstein, found that allowing their minds to wander led to significant discoveries. Einstein’s thought experiments contributed to his theory of general relativity, which predicted gravitational lensing—where massive objects warp space-time enough to bend light from distant sources.
So, the next time you find yourself idly reaching for a device, remember that a little boredom can lead to awesome discoveries. Stay curious!
Speaking of curiosity, thank you to Curiosity Stream for supporting PBS Digital Studios. Curiosity Stream is a subscription streaming service that offers documentaries and nonfiction titles from some of the world’s best filmmakers, including exclusive originals. I’ve been watching “Dream the Future,” a 19-part series that asks leading visionaries to predict what life will be like in 2050. It’s exclusive to Curiosity Stream and narrated by Sigourney Weaver. The first 10 episodes are streaming now, and you can get unlimited access today. For our audience, the first 60 days are free if you sign up at curiositystream.com/smart and use the promo code “smart” during the signup process.
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This version maintains the core content while removing any informal language, filler phrases, and potential distractions.
Light – Light is a form of energy that travels in waves and can be seen by the human eye. – Example sentence: When light passes through a prism, it separates into different colors.
Experiments – Experiments are scientific procedures undertaken to test a hypothesis or demonstrate a known fact. – Example sentence: In science class, we conducted experiments to observe how different materials affect the speed of sound.
Bend – To bend in physics means to change the direction of a wave, such as light, when it passes through different mediums. – Example sentence: A straw appears to bend when placed in a glass of water due to the refraction of light.
Shadows – Shadows are dark areas where light is blocked by an object. – Example sentence: We observed how the length of shadows changes throughout the day as the sun moves across the sky.
Lens – A lens is a curved piece of glass or other transparent material that refracts light to focus or spread it. – Example sentence: The magnifying glass uses a convex lens to make objects appear larger.
Focus – Focus is the point where light rays converge to form a clear and sharp image. – Example sentence: By adjusting the focus on the microscope, we could see the details of the cell structure.
Diffraction – Diffraction is the bending of waves around obstacles or through openings, which can cause patterns of light and dark bands. – Example sentence: We observed diffraction patterns when light passed through a narrow slit in our experiment.
Curiosity – Curiosity is a strong desire to learn or know something, especially about how things work in science. – Example sentence: Her curiosity about the stars led her to study astronomy.
Rays – Rays are straight lines that represent the path of light as it travels through space. – Example sentence: The sun’s rays provide the energy needed for plants to perform photosynthesis.
Umbra – The umbra is the darkest part of a shadow where the light source is completely blocked. – Example sentence: During a solar eclipse, the umbra is the region where the sun is completely obscured by the moon.
