Set up a ring stand that cannot tip
When you design the experiment yourself, nobody hands you the setup. Learn where the clamp goes, where the load sits, and how the stand is put away.
- A stand stays up while its load is over its base: Push the weight out past the edge of the base and the stand tips. Everything else about setting one up follows from that one idea.
- Weight carried higher tips more easily: The same clamp and pipette are harder to knock over near the bench than they are at the top of the rod.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Now think about the space under the setup and the state you leave it in.
A group sets up their stand at the edge of the bench so there is room for their notebooks in the middle. What should change?
Reviewed- A.Nothing, as long as one person keeps a hand on the stand during each drop
- B.Turn the stand around so the drops fall toward the middle of the bench instead
- C.Lower the clamp so a fall from the edge would not travel as far to the floor
- D.Move the stand in from the edge and move the notebooks out of the landing area
Show the worked solution ▾
Answer: D. Move the stand in from the edge and move the notebooks out of the landing area
- Step 1: Name the two hazards: A loaded stand near an edge, and paper in the space something is going to land in.
- Step 2: Fix both: One move handles the stand and one handles the notebooks.
Why it's right: There are two problems and both are solved by moving things. The stand belongs where a knock cannot take it off the bench, and the landing area belongs to the experiment rather than to anyone's notes.
- A: A hand on the stand ties up a person for the whole run and it does nothing about the notebooks sitting in the landing area.
- B: Turning it around moves the drops but leaves a loaded stand sitting at the edge of the bench, which was half the problem.
- C: Lowering the clamp changes the height they were trying to test and still leaves the stand where it can be knocked off.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
The run is finished. What state should the stand and clamp be in when they go back to storage?
Reviewed- A.Assembled but with the clamp slid down to the bottom of the rod
- B.Left standing on the bench, since it will be needed again next lesson
- C.Fully assembled, so the next group can pick it up ready to use
- D.Taken apart, with the clamp loosened and stored separately from the rod
Show the worked solution ▾
Answer: D. Taken apart, with the clamp loosened and stored separately from the rod
- Step 1: Ask what an assembled stand does on a shelf: It takes up height, catches on things, and arrives at the next group set to somebody else's experiment.
- Step 2: Ask what a tight clamp does over time: It is harder to free, and the next group forces it.
Why it's right: Taking it apart means the next group starts from a known state rather than from your settings, and a clamp that goes away loose is a clamp that comes back out without a fight.
- A: Sliding the clamp down helps with height but leaves it tight on the rod and still leaves an assembled stand on the shelf.
- B: Equipment left standing on a bench between lessons gets knocked, borrowed and moved, and the room has to be usable for the class after yours.
- C: A stand stored assembled arrives set up for the last experiment, which is rarely the next one, and it is awkward to store.
Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9
- A student clears the landing area before the first drop rather than after the first spill.
Fill these in as you work through the lesson.
- Base (the heavy foot the whole thing balances on):
- Clamp (holds the pipette at a chosen height):
- Drop zone (everything directly under the load):
- Student-designed (the setup is your decision, so is the safety):
Keep the load over the of the stand and clamp as as the experiment allows. Keep the space the pipette clear, and the clamp before the stand is stored.
- Explain why the same clamp is safer near the bench than at the top of the rod.
- Say which direction the base should point relative to the load.
- Describe what belongs in the space directly under the drop.
You need drops from 40 cm. You turn the base so its longest part points under the pipette, clamp at 40 cm rather than at the top of the rod, and put the paper down where the drops will land with nothing else in that space.