Science Tutor Tips: Thinking about problem-solving

Sometimes a science tutor has to remember not to just give away the answers.

Last week someone asked me what would happen to oxygen in a jar in outer space. I answered on the FaceBook page for Science Tutor Online, but all I really did was blurt out a few possibilities.

Later on, I realized that a real science tutor would help a student to figure out the answer on their own. Thus, I made the following video:

You probably can't take a trip to outer space just to see what would happen to the air in your jar. But you can work with what you already know.

For example, I know that oxygen on earth is usually in the form of a gas. The molecules are moving around inside the jar, and many of these molecules collide with the sides of the jar. This action creates constant pressure on the inside of the jar.

If the oxygen is more dense, the collisions are more frequent and the pressure is greater. Likewise, if the more heat the oxygen contains, the greater the pressure. On earth, we can assume that there is pressure from the air outside of the jar that is roughly equal to the pressure inside the jar.

"Now," says the science tutor, "let's see what we know about space.

Hmm...

In space, there are no gasses on the outside of the jar. This means the pressure on the indide of the jar is much greater than that on the outside. If the seal is not strong enough, the oxygen will leak out around the lid of the jar. If the seal is strong but the jar is weak, the internal pressure might cause the jar to crack, or break completely.science tutor problem-jar in space

Or maybe, if the jar and seal are both strong enough, nothing will happen at all. The oxygen will stay inside the jar forever.

"Forever?" asks the science tutor. "But what about changes in temperature? Or radiation from a nearby star?"

Ahah! Heat or other radiation could increase the temperature of the oxygen inside the jar. This in turn would increaase the pressure and possibly cause a leak or a breakage. Also, its possible that the radiation itself would break the jar.

"One more thing," you ask the science tutor. "What happens if the oxygen gets too cold, and turns into liquid?"

We'll leave that last one up to you.

 

2 Replies to “Science Tutor Tips: Thinking about problem-solving”

    • Jocelyn, the pressure of oxygen on Mars is the same as everywhere else: It depends on the temperature of the oxygen, the number of oxygen atoms (or O2 molecules), the space the oxygen has to occupy, etc. If you took a sealed jar of oxygen from earth and brought it to Mars, and the jar remained sealed and intact, then the only thing that could affect the pressure of the oxygen would be the temperature, or maybe radiation that affectedthe temperature in some way. Glad you liked the vide (or at least had a good laugh at it) 🙂

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