Experiments with Light: An extension lesson with your Periscope Science Kit
So we already learnt previously that light travels in a straight line. Also, light can bounce off objects – a process called reflection! But light can interact with objects in other ways too!
Sometimes, light is able to travel through and out of the object – we call that transmitted light. Other times, light gets absorbed by the object. Whether the light is reflected, transmitted or absorbed depends on the type of light and the material of the object.
Material Properties – Transparent, Translucent & Opaque
Materials like glass and water are transparent. This means that they allow all light to pass through them. We can see objects behind transparent materials very clearly as all the light from the object reaches our eyes!
Translucent materials absorb some light, allowing only some light to be transmitted. That is why we can’t see clearly through translucent materials, often only seeing fuzzy and blur silhouettes with little details.
We cannot see though opaque materials as all light gets absorbed into it. In fact, most materials are opaque in the world! Let’s investigate!
We can investigate the interaction of light with materials by looking at shadows! Shadows are formed when the straight path of light is blocked by an object. Let’s start!
We can observe the difference in the amount of light that reaches the wall from the flashlight. The wall behind the opaque cardboard is dark as the cardboard material absorbs all the light. The wall behind the transparent plastic is bright as the plastic allow all the light to be transmitted. The wall behind the translucent baking sheet is not as bright as some of the light is absorb by the baking sheet.
Size of shadows
How we position our object in relation to light source will affect the size of the shadow formed. The closer the object is to the light source, the greater the amount the light that gets blocked, the bigger the size of the shadow.
Try it out at home! Grab your torchlight and a soft toy and experiment with shadows! Move your torch light closer to the toy or move the toy closer to the torch and watch the shadow grow!