You will need
- A copy of some Kakuro puzzles
- Pencil and eraser
What to do
A Kakuro consists of a grid of boxes, some empty and some filled. Lines of empty boxes run across and down. These lines each have a clue – to the left of horizontal lines and above vertical ones. The aim is to write a digit from 1 to 9 in each empty box following two rules:
- No two boxes in a line contain the same digit
- Adding up all the digits in the line will equal the clue
There are a lot of tricks to this puzzle, so we’ll explain how to solve Puzzle A step by step: Continue reading Try this: Solve a Kakuro
Pine cones respond to humidity. The scales open when the pine cone is dry because the outer half of the scale shrinks more than the inner half. This causes the scales to pull away from the cone. When the pine cone is wet, the scales swell shut.
In dry air, pinecones open their scales and disperse the seeds inside. When it’s warm and dry, the conditions are favourable for seeds to scatter away and grow. Continue reading Try this: Open, shut them
Although the sieve is full of holes, the flame from a candle won’t pass through them. The fire is actually the candle’s wax evaporating from the wick. When you light a candle with a match, you are actually heating the wax near the wick so it turns into a gas, then the heat from the match causes the gas to react with oxygen in the surrounding air, creating carbon dioxide, water vapour and solid carbon (soot). This process releases even more energy as heat and light so the wax-burning continues after you take the match away. Continue reading Try this: All meshed up
There’s a good chance the bananas and tomato you put together in the paper bag will ripen before the other fruit. Why is that?
Technically, a plant’s fruit is simply its ovaries; the organ containing its seeds. Different plants spread their seeds in different ways – some drop them to the ground, and don’t want animals to eat them, while others love birds or mammals munching on them, as this helps spread the seeds further. Continue reading Try this: Going bananas
Psyllium is the common name for a plant harvested specifically for its seeds. The seed’s coat, or husk, contains a large amount of a hydrophilic (water loving) substance called mucilage. When mixed with water, this chemical turns into a translucent, colourless gel. Using hot water simply helps speed up the process. Continue reading Try this: Psylli slime
The candle’s flame heats the surrounding air, creating a warm pocket within the opening of the jar. For this activity to work, the air needs to be absolutely still. Any breeze will blow away the layer of heated air.
Smoke from the incense rises due to a convection current, where the heated gases float above the surrounding dense, cooler air at the bottom of the jar. Yet the warm pocket at the top interrupts this convection current, pushing the rising smoke out towards the sides of the jar and allowing it to cool. The warm layer therefore acts like a ceiling, trapping the incense smoke in the jar. Continue reading Try this: A cup of smog
Once you let it go at the top, your marble will keep rolling unless something stops it. This could be the floor, a container that catches your marble, or a dead end on your run.
As it is rolling, your marble will accelerate. In physics acceleration is more than just an increase in speed. It is a change is something’s velocity. Velocity is the speed of something travelling in a particular direction, and you could draw that movement as an arrow. Any change in the speed or direction of something will result in its acceleration. This could be getting faster, slower or changing direction. Continue reading Make a marvellous marble runner
When an electrical current moves through the wire, the compass turns to follow the direction of the magnetic field around the wire, rather than the magnetic field of the Earth.
Even though we can’t see them, magnetic fields circle around electrical currents, such as electrical wires and powerlines. An electrical current is a flow of electrons.
The greater the electrical current, the greater the magnetic field will be. Magnetic fields will pass through any barrier such as a wall but as you move further away from the electrical current, the magnetic field will decrease. Continue reading Confuse a compass using electricity
To think about air pressure, we have to look up into the atmosphere. Gravity pulls air (and us) to the Earth, and the part of the atmosphere that has the most air is right here, close to the Earth at sea level. As you go up there is less and less air until you reach a point where there is no air at all. The lower layer of the atmosphere that has 75% of all the air in the atmosphere is called the troposphere and it is around 10 km thick above Australia (this layer gets thicker over the equator and thinner over the poles). Continue reading Breaking under pressure
Want to be charmed, fascinated and intrigued? Or perhaps you are sick of the weather report getting it wrong and you are ready to take matters into your own hands. Either way, it is time to become a cloud spotter. Guest writer Beth Askham shows you how. Continue reading Summer cloud spotting
Your brain is an incredibly complex organ that consists of between 15 and 33 billion neurons each forming up to 10 000 connections. Over time it has evolved to look much like a pair of wrinkled prunes squished together.
Each half – or ‘hemisphere’ – coordinates a range of different tasks in your body. In some cases, the left hemisphere controls muscles on the right side of the body, and the right hemisphere controls functions on the left. Both halves also work together on certain tasks in slightly different ways. For instance, the regions mostly responsible for speech, called Broca’s area and Wernicke’s area, are both located in the left hemisphere, while the ability to understand the context of words is controlled by the right hemisphere. Continue reading Vegetarian zombie snack
‘Mock apple pie’ is said to have been made by the American pioneers, who lacked fresh fruit on their travels. Although there is no fruit in the recipe, to the unsuspecting tongue there is the distinct taste of apples.
Your tongue and nose both contain a number of nerve receptors that respond to the presence of certain chemicals. Contrary to what you might have heard about your tongue being divided up into different areas, buds all over your tongue are capable of detecting different tastes. Volatile chemicals evaporate and move into your nasal cavity, triggering smells that also contribute to a food’s unique flavour. Continue reading (Not) Apple Pie
Over the next two weeks, activities will use frozen carbon dioxide – better known as ‘dry ice’. This material can be purchased through some party supply companies or direct from BOC Gases or Air Liquide.
Warning: Dry ice is not like water ice. Do not allow it to touch your skin; the extreme cold can cause harm. Wear thick gloves and safety goggles when doing this activity. Continue reading Sleeping bubbles
At room temperature and ‘normal’ pressure (1 atmosphere), carbon dioxide (CO2) is a gas. Pouring water over the dry ice made it quickly turn from a solid into a gas without passing through a liquid phase. The dry ice itself is so cold the cold CO2 gas it releases chills the water in the air, turning it into a foggy vapour. Continue reading Acidic chill