Atoms in gases
You will zoom inside a helium balloon and see that helium gas consists of atoms that are flying. You will see that atoms in gas are further away from each other than in solids. Finally, you will see how atoms start flying faster if you increase the temperature.
This lesson is a part of MEL Chemistry VR. Learn more →
atoms, matter, state of matter, gas, temperature
- Gases are not matter because we can't see them or feel their mass.
- Learn that atoms in gases are much further away from each other than in solids
- Find out that atoms in gases are flying freely
- See that when the temperature increases atoms in gas start to move faster and when the temperature decreases they slow down
- Be able to compare the density of gaseous objects to solid ones
The goal is to demonstrate how much denser liquid and solid objects are compared to gases. Ask students to determine (make measurements with a set of weights and then count) how many helium balloons a student needs to lift him/her up in the air.
Equipment: balloons filled with helium, set of weights.
The goal is to show students how powerful gas particle motion is. Ask students to pull out a syringe plunger and keep it in place with their fingers. Let them see how easy they can do it. Then ask them to close the hole with their finger and pull out the plunger again. Let them feel that it becomes much harder to hold the plunger so that they can see how rigorously gas particles move and hit everything around.
History and sources of knowledge
- The ancient Greek theory that air was one of the basic elements.
- Discovery of different gases in the air.
- Our knowledge about air as a mixture of gases.
- Particle motion in gases: under a microscope, we can see the Brownian motion of tiny smoke particles in the air. It proves that air consists of tiny particles moving chaotically.
Topics to discuss
- How do we know that there are gas particles around us if we can't see them?
- The speed of gas particles.
- How much denser are solids than gases?
- Billions of gas particles are hitting us, why don't we feel it?
Fun facts and quotes
- If you stretch out the palm of your hand, you actually hold about 100 kg of air.
- The heaviest gas is sulphur hexafluoride. If you pour this gas in the tank a tin foil boat would float on top of it.
- Air is roughly 1,000 times less dense than water. 1 cubic meter of water weighs 1 ton or 1,000 kg, while 1 cubic meter of air weighs approximately 1.3 kg.
- Why can gases change their shape and solids can't?
- Why can gases change their volume and solids can't?
- What is denser gas or solid and why?
In China, one of the world’s fastest trains can reach a speed of 430 km/h (approximately 0.2 km/s). In the air, oxygen particles travel at around 500 m/s. Which is faster oxygen particles or the train?