Your classic rain gauge that you might have made can be made from a water bottle. This principal works great, but fills up.
On a weather station, you have a funnel opening, and underneath is this tipping spoon. The volume of water in the spoon is known, so if you can count the number of times it tips, you can calculate the amount of water.
You will make your own tipping spoon with the materials I give you.
Start like this: 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 spoon.
You are going to design the rest. You will be using a marble instead of water. It needs to start horizontally, tip down when the marble falls in the spoon to dump the marble out, then returns quickly to the horizontal position. (Demonstrate the steps.)
What other design elements will it need? (Write up any that they come up with - weight, stop, but do not add more than they can think of.)
Students can break the materials apart if they need, and take 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 spoon rain gauge in a weather station is finely weighted, balanced and housed so that it works as your models do.