Rocket has two foam cups nested together and a cardboard square with a hole poked through it.
"A heat trap," he says. "The lid and the double cup keep the heat from sneaking out while we measure."
Raven measures vinegar into the inner cup. "Thermometer in first. We need the starting number before anything fizzes."
Nova hovers over the lid. "A good test changes one thing," she says. "What will you change, and what will you keep the same?"
"The baking soda goes in," Rocket says. "Everything else stays." He tips in the spoonful. Foam rises against the lid.
Raven watches the reading settle. "Lowest point, then write it. What do you notice about the gap?"
College chemistry students measure reaction heat with a simple tool. It is two foam cups nested together, with a cover and a thermometer through the cover.
Scientists call it a coffee cup calorimeter. The foam and the trapped air slow heat leaking in or out, so the reading shows the reaction, not the room.
It is not perfect. Some heat still leaks, so the numbers are rough. Rough data is still data, and today yours goes in the Bench Log.
| Test | Start temperature | End temperature | Change | Endothermic or exothermic? |
|---|---|---|---|---|
| Vinegar and baking soda | ||||
| Lemon juice and baking soda | ||||
| Salt in water | ||||
| Sugar in water |
| Lab check | True or false? |
|---|---|
| The thermometer goes in before the baking soda. | ? |
| You should seal the cup tightly so no gas escapes. | ? |
| The temperature change is the end reading minus the start reading. | ? |
| Rough data from a foam cup is still worth recording. | ? |
That is real calorimetry at a kitchen table. Tomorrow you will read measurements made the same way in a university lab.