Explorez tous les épisodes du podcast Great Moments In Science

Dr Karl was first heard on the wireless in 1981 when he convinced Triple J that a talk about the space shuttle would be good listening because he had applied to be a NASA astronaut. The shuttle did (eventually) launch ... and along with it, the all-science-media career of one Dr Karl Kruszelnicki.

This is Dr Karl's last Great Moment in Science, as we know it—but don't worry, he'll still be around and firing on all cylinders—including on Triple J's Science with Dr Karl podcast.

Science with Dr Karl

We know that the drug called cannabis, or marijuana, increases the appetitecommonly called the 'Marijuana Munchies', and we are finally getting closer to knowing what makes it happen. Half-a-billion years ago a biological system evolved to make sure that hungry animals would eat.

The ancient Romans thought that insects were attracted to bright light, and then there's the well-known phrase, "drawn like a moth to a flame", so it seems like people over many years have spotted insects coming into the lights, at night. But what's the real reason?

Host: Dr Karl Kruszelnicki

Some sleepers who act out their dreams are later diagnosed with Parkinson's disease. As Dr Karl explains, it's one of a few slightly odd new diagnostic tools. 

The power of smell can't be understated — our noses don't just sniff out tasty treats, they can also alert us to danger. 

In this episode of Great Moments in Science, Dr Karl tells the story of a super-sniffer who might've unlocked a powerful diagnostic tool.

Atomic clocks are the most precise time-keepers we have.

But that doesn't mean they can escape the timey wimey effects of gravity. 

In this episode of Great Moments in Science, Dr Karl explains how this enables super-accurate clocks to not just measure time, but height as well.  

Humans have been dunking biscuits for as long as biscuits have existed. 

But why do we do it? Why are soggy biscuits so darn good?

In this archive episode of Great Moments in Science, Dr Karl submerges himself into the mechanics of this age-old activity.

Thousands of people will descend on the tiny WA town of Exmouth later this month to witness the Moon block out the Sun for a whopping one minute. 

But if you're a homebody not all that keen on a road trip, how long might it take to see a total solar eclipse from where you are right now?

Dr Karl investigates in this archive episode of Great Moments in Science.

Green potatoes — would you like them here or there? Would you like them anywhere?

Well as Dr Karl taught us last week, potatoes contain a potentially deadly chemical, and a green tinge is its greatest tell. 

In this archive episode, we explore why green potatoes are best avoided. 

Given the right (or wrong) circumstances, the humble potato packs a punch. 

It contains a chemical that could kill if ingested in large amounts. The catch-22? That chemical is exactly why potatoes taste so good. 

In this archive episode of Great Moments, Dr Karl digs into the science. 

What you eat or drink just after you finish pumping iron is crucial to laying down muscle. 

Dr Karl weighs up the best way to bulk up, in this archive episode of Great Moments in Science from 2011. 

The destructive force of a wall of snow is well known. Major avalanches can not only kill, they can also completely reshape a landscape.  

But it's not just mountainsides we need to worry about. There are also avalanches happening under the surface of the ocean — forging canyons and threatening our telecommunications.

There are plenty of reasons why a person might poke their tongue out. 

Sometimes it can be a rude or cute gesture. Maori warriors do it as a sign of defiance, and Tibetans do it as a greeting.

But many times it's a sign of concentration. So here’s why your tongue helps your brain think.

Host: Dr Karl Kruszelnicki

In development is an amazing new technology which may, eventually, turn your thoughts into speech. It's being designed to help people who can’t speak, turn what they're thinking into speech. But it’s still early days.

Athletes are not just fit, they also attract a lot of media attention, especially if stories are put around that COVID vaccines are a cause of death in this group. In late 2021 such claims were being made - and they’re plainly not true.

In 2022 we found that Neanderthal DNA could kill superbugs. Wait, what ... didn't Neanderthals die out?  Yes, but their hidden power could make them important in modern medicine.

Continuing the story about the effects of alcohol we arrive at the “drunchies”—short for the “drunken munchies”. They’re what occur after a bout of too much drinking. You become very hungry and much your way through any fast food within reach.

Host: Dr Karl Kruszelnicki

Alcohol in small quantities can make people sociable; but too much of it can mean hangovers and associated consumption of non-nutritional foodstuffs. There's a whole chemical family of 'alcohols', so what's the deal with the one that humans kinda like—ethanol.

For some snapping spaghetti is sacrilege — but for others it’s science.

From spaghetti strands to trees to nanotubes — we need to know about the physics of rod-like structures.

How do trees face an incoming threat if they can't move, see, or hear?

Trees are solid and dense. However, they're made from air. Wait, what?

About 95 per cent of the mass in the universe seems to be missing — what's going on!?

Our skin is like a personal space suit protecting us from the outside world. Skin is best when you are a child—because of the elastic protein keeping it fresh and supple—but, unfortunately, that freshness doesn’t last.

Host: Dr Karl Kruszelnicki

Producer: Diane Dean

An interesting demographics exercise is to add up the number of humans who've existed. This is different from how many people are in a population—which in late November 2022, is about 8 billion. But using data going back as far as possible, the number of people who've existed is reckoned at over 100 billion.

Host: Dr Karl Kruszelnicki

One might imagine that face masks work because the multiple layers will stop a virus getting through. But no, that's not it—they use a high-tech 'melt-blown' material, developed from a technique first noticed in volcano eruptions.

Host: Dr Karl Kruszelnicki

Producer: Diane Dean

Nowadays we're pretty familiar with wearing a face mask to reduce infection rates, and that some masks are better than others.But understanding why the N95 mask is a really good mask one came as a surprise.

Host: Dr Karl Kruszelnicki

Producer: Diane Dean

Nuclear weapons carry enormous destructive power in a very small package. A nuclear weapon weighing about a quarter of a ton can release as much energy as exploding 1.2 million tons of TNT – that’s a multiplication factor of about five million. During the Cold War the combined numbers of US and Soviet nuclear weapons reached about 70,000. There are not so many these days but there are still enough to end civilisation as we know it.

The further adventures of some of the most powerful events in our Universe: Gamma Ray Bursts. The biggest one recorded was in October 2022, in a galaxy far, far away. What would have happened if it had exploded inside our Milky Way galaxy?

First on the list of Most Energetic Events Ever in our universe is The Big Bang. No mean contender for top ranking is the "Gamma Ray Burst" - aka the GRB. GRBs can put out more energy in a few seconds than our Sun produces in its 10-billion-year lifetime.

The invention of the elevator made city-living possible. It made possible a rapid mixing of cultures and concepts, efficient use of energy—and ultimately, increased economic output. And now there's a further improvement called 'destination despatching'.

The first definite proof of a link between humans and dogs is a 15,000-year-old grave holding a dog, a man and a woman. Intensive breeding of dogs began about 200 years ago, which resulted in most of today's 450-or-so breeds. And there's a definite mutual appreciation society between people and canines

In 2013 the academic journal published an article called, “Taste perception: from the tongue to the testis”. It looked at some of the distinct taste sensations that we register in the Gustatory Cortex - the taste centre of our brain which are picked up by taste buds on the tongue. However, there's a difference between taste buds and taste receptors ... which is where the testis enters the story.

Earth's defence against the existential threat of extraterrestrial rocks has been bolstered. 

But is it really all that important for humanity to have a plan of attack for an asteroid ambush?

It wasn't the first, second or even third issue to come up in the wake of this year's huge undersea volcanic eruption in Tonga. 

But the eruption, and the ensuing tsunamis, did have a far-reaching impact on the kingdom's neighbours and beyond — including on Australia's coastline. 

For a long time our home solar system was all we knew. But since we’ve gotten a better look at other systems near and far, it has become apparent... our solar system is weird.

Dr Karl explains how artificial intelligence detects and distinguishes between look-alikes.

The term 'doppelgänger' goes back centuries, but in recent years the internet has made it much easier to find your look-alike

There's a precise science behind the impact of small, falling objects. Some can be deadly. Others don't pack much of a punch. 

The final installment of why the Earth is suddenly speeding up—after more than a billion years of slowing down. 

How do we measure the rate of the Earth’s revolution, and what happens when the time on our clocks doesn’t quite match up? 

Part 2 of the explanation about the accelerating spin of the Earth - which is against the trend of the last one-and-a-half billion years.

Part 1 about how the Earth is unexpectedly speeding up, and has recorded its shortest day ever – 1.59 milliseconds shorter than the standard 86,400 seconds

Electricity supply is shifting to renewables, so batteries are important. It might even be cheaper to power your house with the battery from your electric car, rather than batteries specifically designed for houses.

Nose-picking is something that people find disgusting—yet we still do it.  And how about the gunk that’s in your nose—is it ok to eat that?

The highest standard for measuring body temperature is via a heart sensor—after that, it's from inside a body cavity; and you can do it from inside the mouth or the ear, but that's not as accurate, and even less so when measured on the skin. Measuring brain temperature is different again—and be astonished that the temperature of the human brain differs from the rest of the body.

Have you ever been winded? You suddenly lose the ability to do something you've done 15 times each minute of your life. It's one part anatomy, one part physiology, and one part don't panic.

Dogs tend to hang around humans but do they really love us—and what’s with the head tilt? Their affability might be due to two genes known to influence sociability in mammals. Gradually genetics turned dogs and humans into best friends.

Measles is a nasty infection that you don't want to get. It can cause death and, what's more, it can also erase your immune system's memory. Only relatively recently scientists have measured this directly - by concentrating on antibodies – which can be generated by natural infection, and by vaccines.

Anticipation is a strange experience. It can take you all the way from hope and trust, to anxiety and fear. But there’s a happy balancing point where anticipation can enrich your life.