This and last week I took part in I'm A Scientist Take Me Out Of Here, a science communication event where school children are able to group chat with you (like on MSN) so they can "meet" a scientist and ask all sorts of science questions. I was in the Water Zone. These are my top 10 favourite/helpful water questions:
1. Where does water come from?
If you mean where did water originally come from, there is some disagreement about whether the source was from, astronomers believe it came from comets or asteroids. They both contain ice and could have collided with the Earth.
2. Why does water have no taste ?
Water itself doesn’t seem to have a taste in that it does not activate the tongue’s taste receptors in the same way that sweet, salty, sour, bitter and umami do. If it doesn’t activate those receptors then it doesn’t have a taste to us. But actually scientists have recently discovered that water does have a “taste”! A study analysed mice’s tongues while they drank water and found that the sour receptor was activated. There has to be a sensor that senses water, so we choose the right fluid to drink and so we know we are drinking. But even though sour sensors on the tongue are activated water has no flavour because of the way in which the receptor is activated.
3. Can you be allergic to water?
Yes, people are allergic to water and it is called aquagenic urticarial. But also we treat drinking water by adding chlorine and you can also be sensitive and have a reaction to chlorine. This is not an allergy but is actually irritant dermatitis (like a chemical burn).
4. What are clouds?
Clouds are a mixture of air, liquid water and solid water, in different combinations
Snow gets light and fluffy when all layers of the atmosphere are below freezing from when it forms to when it reaches the ground. This means the snowflakes don't melt and are formed from lots of tiny ice crystals that have space for air to get trapped inside. The air makes it fluffy- the same as an Aero! But snow can also be heavy. Heavy snow starts off as fluffy snow which gets warmer on its way to the ground and partially melts.
Now hail is different to snow because it is not made of ice crystals but is actually a frozen raindrop, which is generally a lot bigger than a pure ice crystal.
6. Why is there a meniscus in water?
A concave (smile-shaped) meniscus occurs when the particles of the liquid are more strongly attracted to the material of the container than each other.
A convex (rainbow-shaped) meniscus occurs when the particles of the liquid are more strongly attracted to each other than to the material of the container.
So this happens with water in a container because water is a liquid.
7. If you water the plants in your garden with sea water will it affect how it grows if so how?
Plants need a small amount of salt to grow but saltwater has such a high concentration of salt that it can be poisonous to most plants.
If saltwater is poured over a plant, contact with the leaves and stems will not usually harm the plant.
If saltwater soaks the leaves and stays on them for an extended period of time, the water will be absorbed from the leaf, leaving behind just the salt which can inhibit photosynthesis.
If saltwater is absorbed into the soil, the plant tries to absorb it throughout its roots but the salt in the soil actually draws the water out of the plant, dehydrating and eventually killing it.
8. Why does water not move when you spin a mug?
The water in the cup acts as a body separate from the cup. Because of the weak adhesiveness of water to the mug (they are not strongly attracted to each other), the movement of the mug is not transferred to the water.
9. How can water split light like a prism?
Light is “bent” during refraction by different amounts, which separates out the different colours, depending on the colour of the light.
A glass prism produces a spectrum (a rainbow) but a glass rectangle would not because of the way the different shapes bend the light. So if, for instance, water was in a bottle, the shape of the bottle would not be suitable to produce a rainbow. But water droplets in clouds are very symmetrical so can produce a spectrum, like this:
https://www.scienceabc.com/wp-content/uploads/2018/10/raindrop.webp
10. How do two gases (hydrogen and oxygen) make a liquid (water)?
You're right. If you put hydrogen gas and oxygen gas together at room temperature nothing would happen. If you think hydrogen gas is actually H2 (H-H) and oxygen is O2 (O-O) the bonds connecting those two together need energy to be broken
Hydrogen and oxygen are both gases at room temperature because the molecules don’t interact very strongly with one another so they are held quite loose together (like a brother and sister being forced to hold hands). When energy is applied and this bond is broken, the hydrogen and oxygen molecules are strongly attracted to each other because they have opposite charges (like metal and a magnet) so they are held very tightly (like two best friends holding hands) so they bunch together tighter, forming a liquid not a gas.
