It is rare to find families at home doing science experiments together but it is fabulous when you see it in action. It is fun for all and you can get a good discussion going about science and about science at school.
Take a look at this excellent site, from Scientific American:
www.scientificamerican.com/education/bring-science-home/
It will give you a host of ideas. Try this…
Celestial art: Track the Earth’s spin around the sun with colourful shapes!
George Retseck
Key concepts
Light
Shadow
Rotation
Planetary motion
Introduction
When was the last time you really examined the shadows around you? Most people don’t pay much attention to shadows and how they change. That’s because most people don’t think shadows are all that important. But the movement of shadows in sunlight is evidence of something very important, something that it took people thousands of years to figure out—that the Earth spins like a top and orbits around the sun.
Background
Every morning the Earth spins or rotates so that the side you are on faces the sun. As the Earth spins you see the sun come up over the eastern horizon. As the Earth keeps spinning and your day progresses, the sun seems to move across the sky. When the Earth turns so that the side you are on faces away from the sun, you see the sun disappear below the western horizon. From where you are, on the surface of the Earth, it looks like the sun is moving—but it is really the movement of our own planet that makes the sun seem to move and the shadows change.
Materials
A sunny day (for the most dramatic results, try early or late in the day)
A yard, driveway, playground or picnic table
A watch or clock
Coloured chalk of at least four different colours (if sketching on pavement)
Crayons of at least four different colours (if sketching on paper)
A big piece of paper (butcher paper or an unfolded paper grocery bag)
At least four small rocks or other heavy objects to weigh down paper edges
A shadow maker—an object with an interesting shape such as a bottle, toy truck or action figure
Procedure
Find something with an interesting shape to serve as your shadow maker, such as a bottle, a doll, a toy truck or an action figure.
Go outside and find a place where you can see your shadow. Put the big piece of paper on a driveway or sidewalk, or on a picnic table if there is one. Place rocks on the edges of the paper to prevent it from blowing away or moving.
Place your shadow maker in the middle of the paper. Why do you think you would want to place the object in the centre?
Use a crayon or chalk to trace around the shadow maker’s current shadow. Is the shape you trace the same size as the thing? Is it the same shape? What do you think will happen to the shadow’s size, shape and direction as the sun changes position (or more accurately, as we change position in relation to the sun)?
Wait 20 minutes, and then trace the shadow again using a different colour crayon or chalk. Has the shadow moved? Has its size or shape changed?
Continue to trace the shadow every 20 minutes until you have captured the shadow’s movement. How has the shadow changed? Why do you think that is?
Extra: To continue experimenting with shadow art, try some of these changes: trace the shadow every 10 minutes, or every 30 minutes, or once an hour, or once every two hours. How do the spaces between the shadows compare?
Extra: Try the activity at different times of the day. What do the shadow patterns look like in the morning? Around noon? Late in the day? Do you notice any patterns?
