Is it OK to leave device chargers plugged in all the time? An expert explains

YG PhotoArtWorks/Shutterstock Glen Farivar, The University of MelbourneHow many chargers do you own? We’re surrounded by rechargeable electronic devices – mobile phones, laptops, smart watches, headphones, e-bikes and more. You might have a phone charger plugged in next to your bed without ever bothering to switch it off at the wall or unplugging it when not in use. The same might go for a laptop charger by your desk. But is that risky to do? And are there hidden costs associated with leaving chargers plugged in all the time? What’s inside a charger? Naturally, not all chargers are the same. Depending on the application and power requirement, their internal structure can range from very simple to complex. However, a typical charger takes in the AC (alternating current) from the wall plug and converts it to a low-voltage DC (direct current) suitable for your device’s battery. To understand the difference between DC and AC, consider the flow of electrons in a wire. In a DC circuit, electrons move in one direction and keep rotating in the circuit. In an AC circuit, electrons doesn’t circulate and only move back and forth. The reason for why we use both types of current goes a long way back, to the time when inventors Thomas Edison and Nicola Tesla battled over which type would become the default standard. Today, we are...
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What’s the difference between skim milk and light milk?

bodnar.photo/Shutterstock Margaret Murray, Swinburne University of TechnologyIf you’re browsing the supermarket fridge for reduced-fat milk, it’s easy to be confused by the many different types. You can find options labelled skim, skimmed, skinny, no fat, extra light, lite, light, low fat, reduced fat, semi skim and HiLo (high calcium, low fat). So what’s the difference between two of these common milks – skim milk and light milk? How are they made? And which one’s healthier? What do they contain? Skim milk In Australia and New Zealand, skim milk is defined as milk that contains no more than 1.5% milk fat and has at least 3% protein. On the nutrition information panel this looks like less than 1.5 grams of fat and at least 3g protein per 100 millilitres of milk. But the fat content of skim milk can be as low as 0.1% or 0.1g per 100mL. Light milk Light milk is sometimes spelled “lite” but they’re essentially the same thing. While light milk is not specifically defined in Australia and New Zealand, the term “light” is defined for food generally. If we apply the rules to milk, we can say light milk must contain no more than 2.4% fat (2.4g fat per 100mL). In other words, light milk contains more fat than skim milk. You can find the fat content by reading the “total fat per 100mL” on the label’s nutrition information...
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