You may be able to buy coloured rice for your rangoli projects. If not, coloured sand (available from craft stores) makes a good alternative. You can also die your own coloured salt, by simply mixing cheap table salt with food colouring and then spreading it out to dry.
A diya pattern drawn with coloured rice
In traditional rangoli, the outline pattern is drawn on the floor and then filled in by carefully sprinkling coloured powders. Older children could try this technique directly on the ground with coloured sand or salt, having drawn their outline with chalk. Make sure they try this somewhere away from too much foot traffic, and easy to clean!
You will need:
Chalk for drawing a grid or outline
Newspaper to work on
Coloured rice, salt or sand
Large piece dark paper (black construction paper is ideal)
Optional - glitter
You may prefer to draw your outline on a piece of dark coloured paper and then fill in each section with white glue, sprinkling with sand or salt as you would with glitter. Do one colour at a time and shake the excess off onto a large piece of newspaper.
Children could use glitter in some areas of the design for contrast and emphasis.