Speak your mind

FRUIT PRESERVATION

Dear HIW, When I put lemon juice on a cut avocado it stays green longer. What is in lemon juice that prevents browning? Jess Burns

Avocados have an enzyme called polyphenol oxidase (PPO) underneath the skin. When these enzymes are exposed to oxygen, they alter compounds in the avocado and turn it brown. As soon as the avocado’s protective skin is broken, the air makes contact with its flesh and this process begins. PPO is only active when in certain pH conditions, between 6 and 7.5. By adding lemon juice, the pH becomes more acidic and prevents the enzyme from reacting. Covering the exposed surface with this natural preservative soon after cutting the avocado slows browning and can keep the avocado relatively fresh in the fridge for around three days.

Lemon juice has a pH between 2 and 3

BREAKING OLD HABITS

Dear HIW, I have been a nail-biter for years and can’t seem to break the habit. What are the best ways to break old habits?

Nadia Reynolds

When an action becomes a habit it can be difficult to change your ways because the act of biting your nails becomes subconscious. However, if you want to kick a habit, there are some methods that you can use to increase your chances of changing bad habits and replacing them with healthier ones.

Firstly, take note of what you were doing before a habit kicked in, or any common denominators that could be causing you to bite your nails. For example, is it something you do in social situations, when stressed or during a specific activity? By understanding what triggers your habits, you stand a better chance of stopping them. Look for ways in which you can prevent certain scenarios from happening, if possible.

If a habit is caused by something you can’t change, you could try to control your response. One proven method is to find a replacement action and make a conscious effort to do this instead. For example, some people choose to use fidget toys for this purpose. Using these whenever you’re in a triggering situation can help you retrain your mind to revert to habits that are less damaging to the body. This also works for other habits, such as unhealthy eating. Making the effort to eat fruit every time you crave something sweet can cause lasting healthy eating habits over time. Make sure the replacement habit is a simple one, because the simpler the new habit is, the easier it will be for your brain to incorporate it subconsciously. When you have begun this process, remain persistent. The more you try to incorporate a new habit and the more routinely you stick to it, the more likely it is to become a new, healthy habit.

Nail biting is often associated with anxiety

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ANIMAL TALK

Dear HIW, How do animals talk to each other without using words?

Mason Brown

There are many ways in which animals can do this. Some animals use low-frequency calls to communicate over long distances, such as whales, which make different sounds to relay a threat, mating call or other situation. Despite not using words in the way humans do, animals make many other noises that make sense to their species. In addition, non-verbal communication is common in the animal world. Bees, for example, display elaborate dances to describe the location of food sources, dolphins slap their tails on top of the water’s surface to send messages to other dolphins and ants release chemicals to communicate with others in the colony. Each animal has evolved its own method to communicate safely in the wild, and those that can’t be translated by humans and other animals mean their form of communication is safer.

Bees’ waggle dances communicates the direction of food in relation to the Sun and the beehive

HUMAN HIBERNATION

Dear HIW, Could humans hibernate? What makes the biology of hibernating animals different? Charlotte Hill

Humans don’t need to hibernate because we discovered fire, shelter, clothes, hunting and agriculture as ways to stay warm and well fed through winter. Animals that hibernate have evolved metabolic adaptations to survive long periods asleep and without food. Hibernation causes the heart rate and body temperature of the animal to decrease. Summer-loving humans may wish that they could hibernate through the colder and darker months, but because our ancestors evolved in relatively warm regions, we don’t have the same biological capabilities as hibernating species.

Bears can slow their heart and breathing rates by 75 per cent during hibernation

WATER WONDER

Dear HIW, Ice feels heavier than water, so why does it float on top? Benjamin C

A given volume of water will weigh the same after freezing into ice because they are made of the same substance (H2O). When water freezes, its molecules rearrange into a crystalline structure and expand to fill more space. As the same mass of water takes up more space in frozen form, ice is less dense. This is caused by the larger spaces between water molecules. Per unit of volume, water is heavier, and so it falls below the ice. Ice sits buoyant on the water’s surface.

Ice is around nine per cent less dense than water

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