Why is the world's population 50% male and 50% female? Is it softer to run on the road or the footpath? How does skin know to grow back?

Is it better to pick up dog poo or let it fertilize? Do we lose our sense of taste as we get older? Why do I get itchy when I sneeze?

Could our universe be a hologram? Can colliding black holes create musical notes? Will our universe collapse in on itself? Dr Karl and Professor Patrick Hayden from Stanford University answers these questions and more.

Can you teach your eyes to roll away from each other? Is it bad to cough on command? How do relaxation pods work? Dr Karl answers these questions and more, with host Linda Marigliano on triple j Mornings.

Are there different species of humans? Is the earth getting heavier? Why can i put my dreams on hold? Dr Karl answers these questions and more, with guest host Karla Ranby on triple j Mornings.

Do cucumbers feel pain? Do mozzies have a purpose in the world? How do you measure a black hole?

Dr Karl is back at it, answering all your science questions on triple j Mornings. Why do noise cancelling headphones cut out on the train? Why don't spiders get stung by wasps? Is eating boogers healthy?

What makes a planet a planet? Why haven't we gone back to the moon? What'll happen to the International space station when we're done with it? Dr Karl is away for the month, so science journalist Bianca Nogrady is stepping in to be your science sherpa on triple j. Joining her today was Professor Lisa Harvey-Smith, astrophysicist with the CSIRO!…

Dr Karl is away for the month, so science journalist Bianca Nogrady is stepping in to be your science sherpa on triple j. And joining her today was Professor Clare Collins, Nutritionist at the University of Newcastle.

Dr Karl is away for the month, so science journalist Bianca Nogrady is stepping in to be your science sherpa on triple j. And joining her today was Dr Jess Bloom, astrophysicist from the University of Sydney.

Why do you always see dead cockroaches on their backs? Why is bellybutton fluff always dark blue? And could you get drunk from breast milk if the mother has been drinking?

What's 'visual snow'? Why will a dripping tap wake you up but torrential rain won't? Why do some people wake up grumpy?

How do animals that use echolocation travel in packs without it getting confusing? What's salt and vinegar chip-induced eyelid sweat about? Why do you need to go to the toilet when you get home, but not before?

If you wrapped a wire around the world would you generate electricity? How does my partner make her hands sweat on cue? And if I'm allergic to housecats, would I be allergic to a lion?

Why did salt make my beer explode? Why doesn't your entire body wrinkle when you're in the bath? Why dont dogs poo and pee at the same time?

Why does cheese make you dream funny? Why is my dog's poo growing fungus? Why do I see stars when I sneeze?

What causes a sneezing fit? Would your body dissolve in pineapple juice? Is your sense of smell related to your emotions?

Can maths predict the future? What about lotto numbers? Plus, the question that stumped the nation!

Dr. Karl answers all your science questions, including; is coffee linked to cancer? Is there scientific proof of an afterlife? Why can't we control what we remember?

Dr. Karl answers all your science questions, including; can you skip leg day? Why are deep sea creatures translucent? What happens to your body when you're angry?

Dr. Karl answers all your science questions, including; can you get cold sores from a water cooler? Why do we have fingernails and toenails? Is spinach more nutritious when steamed?

Dr. Karl answers all your science questions, including; what happens during metamorphosis? How high do you have to be to see the curve of the Earth? What's the point of shyness?

Dr. Karl answers all your science questions, including; can you prevent sleepwalking? Why do people sing without accents? What will happen if Ben and Liam eat that 11 year old cheeseburger?

Dr. Karl answers all your science questions, including; when will we have wind turbines for our homes? Does the full moon make you crazy? And the ever-important question - what came first, the chicken or the egg?

Dr. Karl answers all your science questions, including; do solar panels work inside cars? Why do some people get bitten by mozzies more often? Do we all see the same colours?

Dr. Karl answers all your science questions, including; why does eye colour change? Is our perception of time Earth-centric? What's the best temperature to cook eggs?

Dr. Karl answers all your science questions, including; what's the deal with fecal transplants? How do preservatives affect your body? Should a grown man eat his vegetables?

Dr. Karl answers all your science questions, including; can you breastfeed after being bitten by a snake? How do you create artificial gravity? How many nutrients are lost in frozen foods?

Dr. Karl answers all your science questions, including; is gravity stronger underground? Is raspberry cordial good for your gut? Which way do toilets flush on the equator?

Dr. Karl answers all your science questions, including; Is fasting good for you? How do bluebottles procreate? Are the magnetic poles changing places?

Dr. Karl answers all your science questions, including; what's the point of hiccups? Should you floss after brushing? Does sound travel in space?

Dr. Karl answers all your science questions, including; can you incubate eggs under your arm? Do all mammals yawn? How does music affect the brain?

Dr. Karl answers all your science questions, including; why is it hard to breathe in humid weather? Why do we twitch while falling asleep? Can caffeine shakes be permanent?

Dr. Karl answers all your science questions, including; do stressful dreams affect sleep quality? Are there really morning and night people? Why do periods sync?

Why does dog poo turn white? What is plasma? Why are bugs attracted to light?

Does Cruise Control use more petrol than regular driving? Do we have UV sensors in our skin? Is there any physical difference between tears of joy and tears of sadness?

Why does everyone have a different sounding voice? When are things wet? Why is milk white?

Does a beer can get colder than when in a stubby bottle? Do ice cubes freeze faster when you use hot water? Why is rainfall measured in millimeters not milliliters?

Does baby oil amplify the sun's rays and give you worse sunburn? What's outside the circle of the universe? Does your internal sense of direction change between the southern and northern hemispheres?

What happens to your brain when you're dizzy? Why do I get goosebumps when I need to poo? Why does it feel weird when you lay on the opposite side of the bed?

Professor David Reilly joins Dr Karl to answer your questions about quantum computing, AI and nanoscience.

Why am I so ticklish? Why is the human eye attracted to sparkly things? How come you can remember the start of a word but not the full one?

Why do you need to wee when you're in the shower? What happens when there's something on the 'tip of your tongue'?' Why do we pull faces when we cry?

Can snakes poison themselves with their own venom? Why do tattoos change colour after getting out of the shower? Does wearing black clothing attract more heat?

Dietitian Professor Clare Collins joins Dr Karl and Zan to answer all your food science related questions. Is naturally occurring sugar in fruit the same as processed sugar? Why do some people hate coriander? What are ketones and what role do they play in the diet?

Bill Nye joins Dr Karl and Zan to answer your burning science questions like: what would happen to the Earth if it stopped spinning? How does the vacuum of space exist? Why is beach sand hard or soft?

It's a Marine Science Special! Professor Emma Johnson joins Dr Karl and Zan Rowe to help answer your ocean-based science questions.

Why do op shops all smell the same? Why can't we use 3D printers to print organs? Is there any benefit to avoiding gluten?

Does forcing a smile really make you happier? Why do certain notes or chords have emotional responses? Is urine good for helping lemon trees grow?

How does addiction work? Why were dinosaurs so big? Does stress shorten your life?