Summary Rain gauges in weather stations use a tipping bucket (or tipping spoon) mechanism. Challenge students to make their own tipping bucket for a marble. Science content Physics: Simple and complex Machines (5) Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7) Earth/Space: Water cycle, Water conservation (2) Science competencies (+ questioning + manipulation + others that are in every activity) Questioning/predicting: predicting (1 up), hypothesizing (7) Planning/conducting: planning investigations (3 up) Processing/analyzing: comparing observations with predictions (1 up) Processing/analyzing: considering alternative explanations (5 up) Evaluating: inferring (3 up) Lessons activity is in Weather - measuring weather Rain and its journey Materials if available: tipping spoon part of weather station with water to demonstrate Per small group: plastic spoon short skewer (or half long) piece of straw, 2cm, that skewer fits smoothly into masking tape, small strip popsicle sticks cup (coffee or plastic) marble modelling clay for teacher: wire [skewer/pop stick] cutters Procedure Your classic rain gauge that you might have made from a water bottle is very simple, but fills up. A tipping bucket rain gauge uses electronics to count the number of times a bucket fills and empties, so can be left to run for long periods. A funnel above the tipping bucket directs rainfall into it. When the bucket is full it tips, then immediately resets. The volume of water in the bucket is known, so if you can count the number of times it tips, you can calculate the amount of water. Image: https://pronamic.com/single-spoon-tipping-bucket-technology/ Second 44 of https://www.youtube.com/watch?v=bAZMItiU5-o Second 15 of https://www.youtube.com/watch?v=5L3nlusjtlk (There are also models with two buckets, which are more accurate in heavy rain, but harder to maintain. See a gif of on of these here: https://www.yoctopuce.com/EN/article/how-to-build-an-usb-pluviometer) Students design their own tipping bucket mechanism with household materials, and use a marble dropped into the bucket to make it work. Show students: insert skewer in straw piece, tape onto spoon at the balance point, making sure it can rotate freely. Secure to cup with clay. It’s like a see saw. We have the rotation part. This pivot is one design element of a tipping bucket. Students design the rest. Use a marble instead of water. The spoon ('bucket') needs to start horizontally, tip down when the marble falls into to dump it out, then return quickly to the horizontal position. (Demonstrate the steps.) What other design elements will it need? Write up any that they come up with e.g. weight, stop - but do not add more than they can think of as they will discover more as they work. Students can break the materials apart if they need, and get more of anything. Once the students have made their designs, ask what other design elements are needed. Complete the list of design elements: pivot, weighted lever, stops to limit movement. The tipping bucket rain gauge in a weather station is finely weighted, balanced and housed so that it works as your models do. It uses a magnet to hold the bucket until it is heavy enough to tip. A circuit detects when the bucket tips, and counts the number of times, to calculate total rainfall over time. Grades taught Gr 4 Gr 5 Gr 6 Gr 7
