Words that start with C

Comets are lumps of rock and ice that travel around the sun. They are usually a few kilometers across. When they get close to the sun, they develop a tail. The tail of the comet always points away from the sun.

Something is compact if it fits into a small space. The car in the picture is a compact car. You can compact something when you compress it together so it takes up less space, for example you might compact the ground before you lay pavers on it.

A competition is where two or more people try and be the best at something. The 'something' can be literally anything that can be judged on some critera of quality, like writing a story, running a race, baking a cake, or growing vegetables, like in the picture. There is usually some kind of prize for winning a competition.

Compost is vegetable matter, rotted down so it can be used to fertilize and improve soil. You can make your own compost from lawn clippings, newspaper, food scraps and fallen leaves. Compost is best kept slightly moist, and turned regularly to aerate it. Worms in your compost will really help the composting process along, as the worms eat the food scraps and their castings become part of the compost.

A surface is concave if it curves inwards, forming a hollow. The coin slot in the picture is concave. The opposite of concave is convex.