2026-03-06 10:51
>>with the HVAC, I can probably reach 18-30C (but it's in a large area vs a small area... current temp 23C or so without HVAC use)
GPT-5 mini
Good—HVAC is ideal for gentle, safe temperature control in that 18–30°C range. Tell me the experiment (what you’re testing and whether you need stable temp, gradients, or repeated cycles) and what instruments you have (thermometer type, containers, sensors). I’ll give a concise, safe setup and measurement plan.
>>I want to see how low and high is possible... but don't have scientific equipment for making frozen nitrogen let alone frozen helium (that stuff is too expensive to buy anyway, and will steam and melt if I was to get it for experiments)... don't have access to lasers or fusion equipment for the tungsten melting (and even plasma-fying) temperatures :|
GPT-5 mini
We can plan a safe, realistic exploration within your available resources. I’ll assume you have: an HVAC (18–30°C control in a large space), a household freezer (~-18 to -30°C), ice/dry ice access (optional), kitchen heating (up to 100°C), and basic thermometers (digital/contact or IR). Here’s a concise, safe plan and what each step can show.
Goals
Find practical min/max temperatures you can produce safely at home.
Measure those temps and observe simple effects (phase change, expansion/contraction, sensor limits).
Equipment to use
Household freezer (document lowest stable temp).
HVAC for controlled ambient (18–30°C).
Hot plate, electric kettle, oven, or sous-vide for controlled heating up to ~100°C.
Dry ice (~-78°C) if available and used with PPE (insulated gloves, goggles, tongs) — optional.
Thermometers: digital probe (ideally K-type thermocouple) and IR thermometer. If only basic probes, note their range limits.
Insulated containers, tongs, glass or metal sample holders, and a timer.
PPE: goggles, insulated gloves, long sleeves, ventilation.
Experiments (safe, practical)
Ambient range (HVAC)
Set HVAC to 18°C, 23°C, 30°C. Let space equilibrate 30–60 min.
Measure air temp at 1 m and 1.5 m height; record stability and variance every 5–10 min.
Purpose: characterize how accurately you can hold ambient temps and how room size affects stability.
Freezer low limit
Place thermometer probe in the freezer mid-shelf; wait until reading stabilizes (30–60 min).
Record lowest stable temp and door-open recovery time.
Optional: test small water sample freezing dynamics (time to freeze).
Dry ice (optional, for colder temps)
Use dry ice only with gloves/goggles, outside or in ventilated area.
Put dry ice in an open, well-ventilated container; measure surrounding air temperature and a metal sample placed near (not touching) the dry ice using a probe with suitable range.
Observe sublimation, fog, and safe handling rules.
Purpose: reach ~-78°C region without cryogens.
Moderate heat up to 100°C
Use kettle/hot plate or sous-vide/oven to reach 60°C, 80°C, and boiling (100°C at sea level).
Use probe thermometer in water for accurate readings; note heater stability over time.
Purpose: verify heating device control and observe effects (e.g., melting, expansion).
Thermal limits of sensors and materials
Check each thermometer’s rated range; avoid exceeding it.
Test small samples (metal rod, plastic piece, ice cube) and observe changes (expansion, melting, brittleness).
Purpose: learn practical limits and safe failure points.
Measurements and recording
Use a simple log: time, set temp, measured temp, device used, notes (stability, anomalies).
Repeat each condition 2–3 times for reproducibility.
Safety notes (must follow)
Never enclose dry ice or produce gases in sealed containers.
Don’t use open flames for high temps indoors; avoid lighters/torches for experiments.
Keep flammables away from heaters; use ventilation.
Wear PPE and handle hot/cold items with tongs or gloves.
If an experiment might exceed consumer gear specs, stop and seek a community lab/makerspace.
If you tell me exactly which samples you want to test and what thermometers you have (brand/model or range), I’ll give a precise step-by-step protocol and the expected safe temp limits for those instruments.
>>oooo dry ice... cool :) ... and for the hottest stuff, I think a cookie can be safely baked at 180C
GPT-5 mini
Great—dry ice is a neat, accessible way to reach much colder temps safely if handled correctly. Baking a cookie at 180°C is an excellent, safe way to explore higher-but-safe temps at home. Below are two concise, safe protocols (dry ice and oven baking) plus measurement tips and essential safety reminders.
Dry ice — simple, safe demo
PPE: thick insulated gloves, goggles, long sleeves; work outdoors or in a very well‑ventilated area.
Materials: chunks of dry ice, an open plastic or metal bowl, tongs, a digital probe or IR thermometer rated below −78°C (if available), a small metal sample or sealed metal container (optional).
Setup:
Place dry ice in the open bowl using tongs. Do not handle with bare hands.
Keep the bowl on a stable surface outdoors (or by a window) so CO2 can disperse.
Hold the thermometer probe near (not pressed to) the dry ice surface or measure the air just above it. If you place a metal sample, set it on a stand so it doesn’t contact the dry ice directly.
Observe fog, sublimation, and temperature readings. Record lowest readings and time.
Notes:
Never seal dry ice in a closed container (risk of explosion).
Avoid confined indoor spaces—CO2 can displace oxygen.
Don’t touch dry ice to skin; treat frostbite immediately if contact occurs.
Baking at 180°C — controlled high-temp experiment
PPE: oven mitts, goggles optional, oven thermometer for accuracy.
Materials: oven with reliable temperature control, oven thermometer, cookie dough or a small test sample, baking tray.
Setup:
Preheat oven to 180°C. Put an oven thermometer near the center rack to verify true oven temp.
Place your cookie/test sample on the center rack; start timer when you insert it.
Log oven thermometer reading immediately after inserting and at intervals (e.g., every 5 min).
Observe sample changes (browning, expansion, moisture loss). Use mitts to remove tray when done.
Notes:
Household ovens vary ±10–20°C; use an oven thermometer for accurate measurement.
Avoid opening the door frequently—this disturbs stability.
Measurement tips
Calibrate/check any thermometer against a known point (ice water ~0°C; boiling water ~100°C at sea level) before experiments.
Use probe thermometers for contact measurements (water, metal); IR for surface/noncontact readings (note emissivity limits).
Record: device, measurement location, time, and conditions (e.g., outdoor wind for dry ice).
If you want, tell me which thermometers you have (model or range) and what specific sample(s) you want to test with dry ice or at 180°C, and I’ll give exact timings and expected observations.
>>"Household ovens vary ±10–20°C" oh
GPT-5 mini
Yes — many household ovens are off by 10–20°C from their set temperature. Causes and quick fixes:
Why it happens
Thermostat placement: the oven’s sensor may be far from the food, so control is based on air at that spot, not the rack center.
Poor insulation or heat loss when door opens.
Uneven heating/hot spots from element placement or airflow.
Aging components or a miscalibrated thermostat.
Simple checks and fixes
Verify with an oven thermometer placed at the center rack while preheating.
If the reading is off by a constant amount, most ovens allow calibration in the settings/menu (consult your manual).
Rotate baking trays mid‑cook to reduce hot‑spot effects.
Preheat longer (15–20 min) for more stable temps.
Avoid opening the door during cooking; use the oven light to check.
Use an insulated baking stone or pan to smooth temperature swings.
When accuracy matters
For experiments or precise baking, use an external probe thermometer or a lab-style oven. For home use, calibrate by testing ice-water (0°C) or boiling-water (~100°C) points to confirm error.
Want a short protocol to test and calibrate your oven with an oven thermometer?
boiling water in the oven is an interesting idea, if it works at 100C (vs 90 or 110C), then the thermostat is correct
GPT-5 mini
Yes—testing with boiling water is a simple calibration check. Here's a short safe protocol:
Prepare
Get a deep pot or metal can, a reliable instant‑read or probe thermometer, oven mitts, and an oven thermometer (optional).
Fill the pot with water (enough to cover the probe tip if using a probe thermometer).
Boil on the stove first (optional sanity check)
Bring the water to a rolling boil on the stove and verify your thermometer reads ~100°C (adjust for your elevation: see note below). This confirms the thermometer works.
Oven test
Preheat the oven to 100°C (or 180°C if you want to check at a typical baking setpoint—use 100°C for the boiling point test).
Place the filled pot (uncovered) on the center rack. Put the oven thermometer nearby on the same rack if you have one.
Insert the probe thermometer into the water so the tip is immersed but not touching the container wall or bottom. Close the door.
Wait 10–20 minutes for the oven and water to equilibrate. Check the thermometer reading in the water.
Interpret
If the water reads ~100°C (within ~±1–2°C, adjusted for elevation), your oven’s actual temp near that setting is likely accurate.
If the water is significantly below (e.g., 90°C) or above (e.g., 110°C), the oven thermostat is off or there are heat distribution issues.
Optional: repeat at other setpoints
Repeat using oven set to 180°C (or your typical baking temp) and monitor oven thermometer rather than boiling water—water won’t boil at those temps, but the oven thermometer shows actual air temp.
Safety notes
Use oven mitts when handling hot pots.
Don’t seal the pot; steam must escape.
At high altitude, boiling point is lower—adjust expectations (e.g., at ~2,000 m / 6,560 ft boiling point ≈ 93–94°C).
If you tell me your elevation or city, I can give the exact expected boiling point for comparison.
>>and boiling is when the thing bubbles a lot? (coz even 60C hot water can 'steam'... the cold tap was 15C in winter, maybe room temp 17C and hot tap 60.5C)
GPT-5 mini
Yes — boiling is when water forms vigorous, continuous bubbles throughout the body of the liquid (a rolling boil). Key phases:
Warm (30–50°C): no visible steam, just heat.
Hot (60–80°C): steam/visible vapor rises, but only occasional small bubbles at the bottom or edges.
Near boiling (~90–99°C): more frequent bubbles, rising and breaking at the surface.
Boiling (≈100°C at sea level): continuous, vigorous bubbling across the whole pot and strong steam.
Notes:
Steam can appear at lower temps from a hot surface or small volume (e.g., 60°C water gives visible vapor); that’s not boiling.
Boiling point lowers with altitude (e.g., ~95°C at ~1,500–2,000 m). If you tell me your elevation or city, I can give the expected boiling point for your location.
>>the elevation is 0-100m, feel free to give estimates for both ranges
GPT-5 mini
At 0–100 m (near sea level): pure water boils at about 100.0°C (±0.1°C).
At ~100–200 m (still effectively sea level): boiling point ≈ 99.9–100.0°C.
Practical notes:
Expect ±0.5–1.0°C variation from dissolved salts/impurities and instrumentation error.
Rolling boil = vigorous, continuous bubbles throughout the liquid; visible steam alone ≠ boiling.
If your thermometer reads ≈100°C during a rolling boil, your thermometer and local pressure are effectively at sea-level norms.