Great Moments In Science - With Dr Karl Kruszelnicki

It used to be thought that a pathogen (or germ) and its host develop in a 'mutually benign relationship'—this was called the 'Law of Declining Virulence'. If the common cold killed us there would be less hosts and the virus would decrease. So the common cold virus mutated to become less lethal, and more common. The Law of Declining Virulence was debunked in the 1980s, and the pathogen/host relationship is actually pretty complicated.

Power steering on a car involves various rods of steel moving relative to one another. How the rods connect is why mechanics are dealing with an unexpected problem.

Thanks to some fuzzy-looking photos, bat echolocation just got more amazing. This program was originally published on 3 September 2019

Why do some people get headaches from eating ice-cream or drinking something very cold. This program was originally published on 19 February 2019

It's not just their ability to run 42 kilometres that separates marathon runners from the rest of us. They've got a secret energy source in their gut. This program was originally published on 5 November 2019

Combustion engines are marvels of engineering and power, but will they feature in the cars of the future? This program was originally published on 8 October 2019

When a balloon pops, sometimes it leaves lots of small fragments of rubber, and sometimes it leaves just a couple of larger pieces. What's going on? This program was originally published on 14 May 2019

Some birds, especially parrots, songbirds and the entire crow family, are surprisingly intelligent - and not just compared with other birds.

Bird poo is usually coloured white—because of the way birds excrete excess nitrogen. But the poo can sometimes be a different colour—because of their diet. Creatures have evolved three main ways of getting rid of excess nitrogen.

Australia is very sunny, and because of that it's a skin cancer hotspot. UV light triggers skin cancer but sunscreen blocks UV light—so is it better to apply more? Not really—and do not mix your sunscreens because there are two different types.

Even in this day and age there are people who think that the earth is flat. The educated people of ancient Greece - about two and a half thousand years ago - had already figured out that the Earth was round. They observed the data that was right in front of them.

When diving to very great depths the body has mechanisms to cope - on the way down, and then back to the surface.

Free diving has a current world record of around 214 m straight down—that's greater than the height of 50-storey building. For thousands of years free divers would collect salvage from shipwrecks to build underwater barricades against invaders.

The benefits of natural foods have always been a big deal. And there really is a tiny nugget of truth in the proclamations—but it's been greatly hyped

We’ve been flying planes with engines for over a century, so have a guess at the record for the longest duration of powered flight - more than two months! And it was set more than half a century ago.

Further intel on a mistruth being spread by social media - that COVID-19 vaccines can cause both male and female infertility. With males, the COVID disease can cause infertility, the COVID vaccines do not. The false claim about female infertility was that the vaccine would make the woman’s own immune system attack her natural proteins. No studies have proved this claim.

We have several pretty good COVID-19 vaccines. They have enormously reduced the risks against getting sick, or dying from COVID. So why are people saying “no” to COVID vaccines? It seems the main reason for avoiding the very protective vaccines is wave after wave of misinformation and dis-information in social media. Let's make some aspects easier to understand.

Science is meant to be about data and logic, and yet that doesn't always stop it from being discriminatory. Women in science don't always get the recognition they deserve, but they have made extraordinary contributions.

If an equinox is truly equal, it should fall on a day when there's just as much darkness as there is daylight. But that's not always exactly the case, so what's going on?

What happens when two stars eat each other to death? And does one get the last laugh in this tale of cosmic cannibalism?