Making our Own Weir

Lately I have been inspired by the blog Science Sparks which is all about doing simple scientific experiments with young kids. As a result, I have been on the look out to add a bit of science into our activities... and the perfect opportunity arose.

The real weir

We were at a park the other day after some heavy rain. This particular park has a series of drainage weirs leading into wetlands. The top weir was draining into a lower pond – causing a waterfall. Cakey was very interested in this and wanted to know why and how. Her questions got me thinking about how I could demonstrate it to her rather than trying to explain.

Setting up our weir

When we got home we got to work making our own weir. I cut out a small section in the side of an ice cream container to mimic the real weir and then placed it into a big tub. We then weighted the ice cream container down with rocks. Cakey added a small amount of water to the bottom of the tub and I mixed in a few drops of blue food colouring. I then added a few drops of yellow food colouring to the ice cream container.

Adding water with a jug

We were all ready! Cakey began to pour water into the ice cream container. As the level reached the cut-out section the water started to cascade over, making a little waterfall. The yellow water from the container mixed with the blue water in the tub and turned green.

This experiment worked really well. Cakey was excited because she was creating her own waterfall and Boo was excited because there was coloured water to play with.

Adding water with the hose

We repeated this experiment over and over, using a variety of different food colouring to watch the mixing effects as the weir overflowed with a cascade of water.

Linked to The Kids Co-op, Fun Sparks, It's Playtime and Learning Laboratory