Standard Resistance Box Chemical_Sodium Citrate Dihydrate and ponds using an alternating

and ponds using an alternating black-and-white Secchi disc visible through the clear 100cm tube during turbidity sampling

Open-top cylindrical dropping funnel in borosilicate glass holds 50mL with PTFE key stopcock for controlled liquid addition in chemistry procedures

Vertically pivoting magnetic needle that visualizes the dip angle of Earth's field

Corrosion-resistant copper British-pattern rain gauge with a weather-grade body

Cylindrical dropping funnel in borosilicate glass holds 100mL with PTFE stopcock and 19/26 plastic stopper for controlled liquid addition

Standard Resistance Box Chemical_Sodium Citrate Dihydrate and ponds using an alternatingTen coil resistance box of identical 10 ohm 2W plus or minus 1% units, letting students wire any combination of series and parallel sections to demonstrate how known resistances combine.