A new use for digital multimeters has been successfully trialled in New Zealand, and is helping students come to grips with "the nature of science".

Inexpensive sensors permit a wide range of environmental data collection for mathematics as well as science classes. Students go through a cycle of "build, test, use" with an example activity provided at the link below;

http://www.nexusresearchgroup.com/technical-data/multimeter-sensors.htm

One possibility is to add the multimeter to the stationary list that students purchase themselves. They could then use their own meters to carry out homework and bring data back to class for analysis.
This means almost no cost to the school. Also, students could brainstorm and develop new sensors; most of the ones I use are only a few cents each.

I have had primary and secondary school students carry out both qualitative and quantitative investigations and had a lot of fun at the same time.

I wanted to share this with other teachers.
I am happy to share ideas and technical advice if requested. Email address on the home page of the Nexus site.