My son, second grade, is doing states of matter. We were trying to help him label different examples for solid, liquids, and gasses. In his science textbook, it mentions that you can’t see a gas and that steam is a liquid because it’s just water suspended in the air, but on his worksheet, by a different source, has fog and smoke as an example of a gas. I’ve always thought of smoke as a gas on a base level. I understand that there are particles being suspended in the air that you can see, but can someone help the states of matter so I can help my son with his homework.
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All particles are moving, solids are tightly parked particles that can only vibrate in place, liquids are particles that have a little more space around them and can slip past each other as they vibrate, gases have more distance between the particles and do not touch.
Fog is water vapor, a gas, and so is steam. Room temperature water is a liquid and ice is a solid. Hope this helps. I wouldn’t get too technical with a second grader.
Smoke would be an example of a Colloid – one thing suspended in another.
Steam *is* vapourised water. We see the water droplets that form as it cools.
The suggestion that gases are all invisible is nonsense – I can’t even think what they intended to say.
1) Solids–atoms have a relatively small amount of thermal energy. They (for the most part) do not have sufficient energy to break free from the relatively large inter-molecular forces holding them together. They will hold their shape without assistance.
2) Liquids–atoms have enough energy to freely move around each other, but are still bound by relatively strong intermolecular forces. Liquids will conform to the container that they are placed in, but will settle towards the bottom of the container in a clump.
3) Gas–atoms have sufficient energy to break free from the inter-molecular forces. They will travel relatively freely. Gases will conform to the container that they are placed in. They will tend to occupy the entire volume of the container. Smoke is NOT a gas. It is a suspension of SOLID particles in a gas. Fog is NOT a gas. It is a suspension of LIQUID particles in a gas. Steam IS a gas. Steam is not what you see coming out of teapot–steam is transparent like most gases. The stuff coming out of the teapot is suspended liquid water droplets in a gas (steam and air).
4) Plasma–you didn’t include this one, but it is a commonly accepted and known state of matter. In a plasma. the atoms have so much energy that some of their outer electrons are set free (they’re no longer bound to the atom). Plasma is essentially an ionized gas and exists at very high temperatures. A lightning bolt is a streak of plasma in the air.
5) Bose-Einstein Condesate–depending upon who you ask this may be a fifth state of matter. This is a state in which a large number of bosons (integer spin particles) have such low energy that they exist in the same quantum state. Fermions (half-integer spin particles) do not exhibit this state since they abide by the Pauli Exclusion principle which prevents them occupying the same quantum state. An example of a bose-einstein condesate is liquid helium cooled down to a couple K above absolute zero.
> it mentions that you can’t see a gas and that steam is a liquid because it’s just water suspended in the air
Incorrect on all counts. Some gasses are easier to see than others though; for example chlorine gas is a greenish yellow in color. Steam is not a liquid, it is a gas, however when it is condensed into a visible cloud it is tiny droplets of liquid water which you see. The actual steam itself is transparent.
> his worksheet, by a different source, has fog and smoke as an example of a gas.
Those are also both wrong. The fog is tiny droplets of liquid water not a gas, and smoke is composed of tiny solid particulate. Neither of them is a gas.
Ultimately the issue is that your son’s educational material is garbage. My suggestion is to meet with his teacher and talk about the technical accuracy of his education, or he will end up like most everyone else these days with fundamental misconceptions about basic science.
Fog is small liquid water droplets in the air. Water as a gas i invisible.
Look at a t a pot of water you boid on the stove. You can boil away all water and never see anything escaping. That is because it is water as a gas that have left and it is invisible. That is if the air is hot enough like typically indoor air.
If you do that out a cold winter day there can something white that you see leav the pot. That is water too it has just been cooled down by the cool air and considered to small liquid water droplets. So if you cool down water as gas enough it condensate to water as a liquid and you can see it.
You can compare it to the moisture of you own breath, not visible when it is warm but can bee seen a cold day day.
Notice I have not use the word steam there is a reason. Steam have multiple usages. What most people thing of steam is something white that you see is released by for example a old steam locomotive. That is wet steam that is a mixture of water as a gas and water as liquid Droplets. It is the liquid droplets you can see.
There is also dry steam that is just water as a gas ant id it not visible.
It is a bit of a simplification that you can see a gas. Gas particles can interact with light and scatter it. The sky is blue because gas in out atmosphere scatter more blue then red light. The same way water as a gas scatter light.
The smoke from a fire will be liquid and solids. Lets just look at a wood fire. If there is lot of white smoke that will be a result of water and what you can see is water as small liquid droplets. The black/gray smoke you can see will be soot. So small particle of unburned solid material, it will primary just be carbon, that is a result of a uncomplete combustion of the wood.
There will be gases too. When you burn wood the combustion produces are primary carbon dioxide and water. In cold air that water can condeate back to a liquid but in warmer condition you can have a invisible exhaust.
This is if the combustion is complete, if not you will have unburned sooth that you can see. Take a look at [https://youtu.be/07P-6gqYg2g?t=23](https://youtu.be/07P-6gqYg2g?t=23) that show two different burn barrel design where one provide a flow of hot air and you get complete combustion and the other do not. It show the visible smoke is a result of incomplete combustion in dry wood.
If it sticks together and keeps its shape, it’s a solid.
If it will spread out to fill its container but stays stuck together, it’s a liquid.
If it doesn’t stick together and just spreads out to fill its container, it’s a gas.
Before anyone starts coming at me with exceptions, the kid is 2nd grade, this is specific enough.
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