Activity

Magnetite in beach sand

Summary
Use a magnet to separate grains of magnetite from beach sand. Can be used to discuss how magneto reception might work.
Science content
Biology: Sensing, Organ Systems (4, 5, 6)
Earth/Space: Rock cycle, Earth Materials, Natural resources (5)
Lessons activity is in
Materials
  • small ziplock baggies
  • beach sand containing magnetite e.g. Vancouver beaches
  • magnets
Procedure

If sand gets on the magnet, it is hard to remove, so:
either put a magnet in a baggie, then move it over a pile of sand,
or put some sand in a baggie, then move the magnet over it.

The magnetite grains in the sand will be strongly attracted to the magnet.
Using the magnet, the dark grey magnetite grains can be separated from the rest of the rock types in the sand.

Magnetite is a mineral containing iron.
It is the most magnetic of all naturally occuring minerals on Earth.
Small grains of magnetite are very common in igneous and metamorphic rocks.

Discussion on magneto reception in animals:
Bees, as well as bacteria and many migrating animals like birds and turtles can sense the Earth’s magnetic field and the patterns it makes. They use it to migrate with the seasons, and to map and find their breeding and feeding grounds.

Bird migration map:
Bird migration: https://www.allaboutbirds.org/news/mesmerizing-migration-watch-118-bird…

We don’t know exactly how magneto reception works - we are still researching how.
One theory is that the tiny magnetite particles found in some animals (in bird beaks and fish noses) are attracted to the magnetic field of the Earth. The magnetite signals which way is North, and is also sensitive to the variation in magnetic field strength in different places across the Earth.
Another theory involves a protein in the retina of animals' eyes.

Magneto reception is found in these animals:
arthropods incl. insects - honey bee, fruit fly, ants
molluscs - sea slug
fish - salmon
amphibians - salamander, newt
reptiles - turtles
birds - canada geese etc etc
mammals - brown bat
humans - we don’t know of a behavioural change, but an affect on our alpha brain waves has been found

Grades taught
Gr 4