The wonderful world around us! Quiz

Answer: Burning wood releases energy

Burning requires a fuel (wood), oxygen from the air and a source of ignition (a match!). Burning, called combustion, is a chemical reaction that releases energy from the chemical bonds that make up the wood and this energy is released as heat.

Answer: The plane's forward and upward forces are stronger than gravity

Gravity will pull any object towards the earth. The forward power from the engines, combined with the shape of the wings which give lift when traveling through the air overcome gravity, allowing the plane to fly.

Answer: Water in the corn turns to steam and expands, popping the kernel

Corn, like most food, contains water, and when the corn is heated, the water turns to steam which takes up more space than water. This expansion causes the tough outer kernel of the corn to split suddenly, causing the popping sound.

Answer: It contains a green pigment called chlorophyll

Many plants, including grass, contain the green-colored pigment called chlorophyll. This natural compound helps trap sunlight, in the process of photosynthesis, which provides the energy needed for the plant to grow.

Answer: Ice is not as dense as water

Ice and water are the solid and liquid forms of the same chemical, H2O. Very unusually, the solid form is less dense than the liquid and hence the ice floats.

Answer: Small particles eroded from rocks in the landscape

Sand is mostly made up of small particles, or grains, of quartz (silicon dioxide) that have eroded (worn away) from large rocks such as granite. Different sand colors come from a range of minerals that can occur in small amounts in the quartz grains.

Answer: A volatile chemical is released that causes tears to form in the eyes

Cutting up the onion releases a volatile, organic chemical called thiopropanal S-oxide. Being volatile, it moves through the air to where it irritates the nerves around the eye, forming tears. As this chemical is water soluble, cutting the onions under a stream of flowing water minimizes this problem!

Answer: The speed of sound is much less than the speed of light

Lightning and thunder both come from electrical discharges between the clouds and the ground. From the same discharge, lightning will always be seen first as the speed of light is about one million times faster than the speed of sound.

Answer: A small piece of rock from space burning up as it enters the atmosphere

A shooting 'star' is not a star! It's a piece of rock flying through space at high speed that then enters the earth's atmosphere where the rock becomes extremely hot. This heat is released (in part) as visible light.

Answer: As part of their sensory system

A cat's whiskers, called vibrissae, are highly sensitive to touch and help the cat move around the environment. The whiskers are about as wide as the cat's body, so if the whiskers don't go through a gap, the cat knows it can't fit its body through either. Cats should have shallow, wide food bowls so that the whiskers aren't aggravated when trying to eat.