Five Fab Facts - Frogs
Earth needs your help! Our environment and the fragile creatures that live on it are sensitive and need to be cared for. In this feature, prepared for environmentally conscious students and adults everywhere, we'll learn about one of the most sensitive animals: frogs. A three-year survey in 2004 by 500 scientists in over 60 countries found that of 5743 known amphibian species:
- A third were threatened with extinction (compared to 23% in mammals)
- Over 427 were critically endangered and may be gone right now
- Half of populations were in decline
- 22% were so poorly understood we can't even tell
Human activity, including pollution, hunting and habitat destruction, are mostly to blame. There's heaps of way YOU can help - build a frog pond, don't pollute waterways, protect frog habitats, use biodegradable detergents and never use chemical pesticides.
1. Frogs in space
Scientists are worried that when humans spend a long time in space their muscles might waste away due to zero gravity and inactivity. Some frogs have the ability to 'aestivate', a kind of deep sleep, for up to nine months without any muscle wastage. Scientists are discovering the frog's secrets, like producing their own antioxidants. They hope to use the knowledge to help astronauts.
2. Sticky solutions
Australian frogs from the genus Notaden ooze sticky liquid through their skin. If an insect strays too close, it will get completely stuck. The frog then turns it into a tasty snack. The ooze is so sticky it will even stick to Teflon, the stuff non-stick frypans are made of. Remarkably, scientists have used the sticky liquid to make glue to repair bones.
3. Frogs show the health of our planet
Frogs are 'bioindicators', as they indicate the health of our environment. Frogs are good bioindicators because they have permeable skin (almost like a sponge), which soaks up chemicals. They also live on land and water, unlike most animals. These two facts make them very vulnerable to any pollution humans produce. Have a careful listen one evening at a local pond, creek or dam - if the frogs are croaking loud and long it shows a healthy environment.
4. Bushfire survivors
By digging up to one metre underground, hiding in cracks or fleeing to moist creek beds, frogs survive fierce bushfires. Curious scientists in Africa found that just playing recorded fire sounds had frogs leaping for their lives. The clever little creatures pop their heads up, have a look around and then hop like crazy to the most fire-resistant vegetation or moist hideaways.
5. Long jump champions
Frogs can jump over 10 times their own body length and the longest frog jump on record is claimed to be over 10 metres!
Hands On!
In this activity you will make a film canister fly. If you like, you can decorate your canister so it looks like a jumping frog.
You will need:
- A white film canister
- Baking soda (sodium bicarbonate)
- Vinegar
- A Paddle Pop stick or teaspoon
- A plate, saucer, tray or similar
- Glasses, sunnies or safety goggles
- An adult
WARNING: This activity involves a flying projectile. Make sure you have an adult with you and wear eye protection. Do this activity outside and NEVER point your canister rocket at ANYTHING, except the sky!
What to do
- Take the lid off the film canister. Before adding the ingredients, practice putting on the lid and placing upside down as described in step 4.
- Put on your eye protection.
- Pour a small amount of vinegar, about 5ml deep, into the canister body.
- Using the teaspoon or Paddle Pop stick, place enough baking soda to fill the recess in the lid.
- Hold the body of the canister in one hand and the lid in the other. Quickly and firmly press the lid completely on, place the canister lid down on the plate and stand back. Make sure your plate is level.
- Your canister rocket will blast off seconds later. The exact timing will depend on the canister, temperature, amount of ingredients and how much you packed the baking soda in.
- Have close look at the lid and bubbling ingredients left on the plate.
Making your own toy frog
You can decorate your canister and turn it into a chemical powered jumping frog toy. Green pipe cleaners make cute legs and you can draw on a frog's face in permanent marker. If you can find a picture of a frog, especially a cute one, you could try sticking it to the canister.
What's happening?
When vinegar and baking soda mix together, there is a fast chemical reaction that produces carbon dioxide gas (C02). As more and more carbon dioxide is produced, the bits of carbon dioxide (called molecules) are squashed together and pressure builds up inside the canister. Pretty quickly, the pressure pops the lid off, launching the canister into the air.
These pages were prepared by CSIRO's Double Helix Science Club.