Time is something we all use throughout our lives, although many of us probably don’t think about how it work – we just get on with it!
Us humans divide time up into small chunks, like hours and minutes and seconds; or into bigger chunks, like days, weeks, months and years. And we measure time by looking at clocks or watches or calendars.
Animals and plants and other creatures also measure time but they don’t use clocks – they rely on the amount of light to tell if it’s day or night, and they sense more gradual changes in the seasons.
Time-travel, or the ability to move backwards or forwards through time, is an idea that pops up in stories and films. But could it actually happen?
Light is all around us. The Sun shines on the Earth every day and we use electric lights or candles to light our homes, schools and workplaces. We use torches or streetlights when we are out and about at night and build fires for light and warmth when we go camping. Even in the middle of the night, there is some light from the stars in the sky.
But one of my daughter’s schoolfriends asked me how light is made. And her brilliant question made me think about natural and man-made light sources.
So, let’s find out more about light – what it is and how it is made…
This week, my daughter has been thinking about stars: “They’re not just twinkly spots in the sky – they must be made of something,”she says. “But what are they made of? And how did they get up there?”
The Sun is the star at the centre of our solar system. It’s millions of miles away but we can feel some of its warmth here on Earth. My 6-year-old wonders: why is the Sun so hot?