I believe these have been around for some time. However, being old don't make them less funny.
This is a list of comments from test papers, essays, etc., submitted to science and health teachers by elementary, junior high, high school, and college students: It is truly astonishing what weird science our young scholars can create under the pressures of time and grades. The spellings are the original ones.
1. H2O is hot water, and CO2 is cold water.
2. To collect fumes of sulphur, hold a deacon over a flame in a test tube.
3. When you smell an oderless gas, it is probably carbon monoxide.
4. Water is composed of two gins, Oxygin and Hydrogin. Oxygin is pure gin. Hydrogin is water and gin.
5. A super saturated solution is one that holds more than it can hold.
6. Liter: A nest of young puppies.
7. Magnet: Something you find crawling all over a dead cat.
8. Momentum: What you give a person when they are going away.
9. Vacuum: A large, empty space where the pope lives.
10. Artificial insemination is when the farmer does it to the cow instead of the bull.
11. The pistol of the flower is its only protection against insects.
12. A fossil is an extinct animal. The older it is, the more extinct it is.
13. To remove dust from the eye, pull the eye down over the nose.
14. For a nosebleed: Put the nose much lower that the heart until the heart stops.
15. For head colds: use an agonizer to spray the nose until it drops in your throat.
16. Germinate: To become a naturalized German.
17. The tides are a fight between the Earth and moon. All water tends towards the moon, because there is no water on the moon, and nature abhors a vacuum. I forget where the sun joins in this fight.
18. Blood flows down one leg and up the the other.
Have a good day.