Instructions
Today, you're going to be a light scientist! You will conduct a few simple experiments to investigate how light travels and what happens when its path is blocked. Follow the steps carefully and record your observations like a true scientist.
Materials You Will Need:
- A torch (a phone torch works well)
- Three pieces of stiff cardboard (about A5 size)
- Scissors
- Something to make the cardboard stand up (e.g., modelling clay, small blocks, or bookends)
- A small object (like an eraser, a small toy, or a pencil)
- A small mirror (optional, for the bonus activity)
Part 1: The Straight Path of Light
Light seems to go everywhere, but does it travel in a straight line or a wiggly path? Let's find out!
Setup:
- Ask an adult to help you carefully cut a small hole (about the size of a 10-cent coin) in the centre of each of the three pieces of cardboard.
- Use your modelling clay or blocks to stand the three pieces of cardboard up in a straight line, about 15cm apart from each other.
- In a dimly lit room, place your torch so it is pointing at the hole in the first piece of cardboard.
- Look through the hole of the last piece of cardboard. Adjust the cardboard pieces until you can see the light from the torch shining all the way through.
Prediction:
What do you think will happen to the light you see if you move the middle piece of cardboard just a few centimetres to the side?
My Prediction:
Observation & Analysis:
Now, gently slide the middle piece of cardboard to the side. What happened to the light? Why do you think this happened?
My Observation:
This experiment shows that light travels in _________________ lines.
Part 2: Investigating Shadows
A shadow is created when an object gets in the way of light. Let's explore how shadows can change.
Setup:
- Remove the cardboard pieces.
- Place your small object (eraser or toy) on a table or the floor.
- Shine the torch on the object to create a shadow on the wall or floor behind it.
Investigation:
Answer the following questions based on your observations.
- What happens to the size of the shadow when you move the torch closer to the object?
- What happens to the size of the shadow when you move the torch further away from the object?
Conclusion:
Complete the sentence below.
A shadow is an area of darkness formed when an opaque object ______________ the path of light.
Part 3: Bonus - Bending Light!
Can you make light go around a corner? You can with a mirror!
Challenge:
Place a small object (like your eraser) behind a barrier (like a book standing up). Using your torch and the mirror, try to shine a light on the object without pointing the torch directly at it. This is called reflection.
Draw Your Solution:
In the box below, draw how you set up your torch, mirror, and book to successfully light up the object. Use arrows to show the path the light took.
My Drawing:
In your own words, what does reflection mean?
Answer Key
Part 1: The Straight Path of Light
- Prediction: Your prediction could be something like: "I think the light will be blocked and I won't be able to see it anymore."
- Observation & Analysis: The light disappears / is blocked. This happens because the holes are no longer in a straight line, and the middle piece of cardboard is now blocking the straight path of the light.
- Fill in the blank: This experiment shows that light travels in straight lines.
Part 2: Investigating Shadows
- Move torch closer: The shadow gets bigger and its edges might become fuzzier.
- Move torch further away: The shadow gets smaller and its edges become sharper.
- Conclusion: A shadow is an area of darkness formed when an opaque object blocks the path of light.
Part 3: Bonus - Bending Light!
- Drawing: The drawing should show the light from the torch hitting the mirror and then bouncing off the mirror at an angle to hit the object behind the barrier. Arrows should show this path.
- Reflection definition: Reflection is when light bounces off a surface, especially a shiny one like a mirror.