diff --git a/book/content/modelling/07_particles/02_example_spray.ipynb b/book/content/modelling/07_particles/02_example_spray.ipynb
index 42343103..1a99feb9 100644
--- a/book/content/modelling/07_particles/02_example_spray.ipynb
+++ b/book/content/modelling/07_particles/02_example_spray.ipynb
@@ -24,7 +24,7 @@
     "  &SPEC ID='water', SPEC_ID='XXX' /\n",
     "  ```\n",
     "\n",
-    "* `PART`, define the particle species for the water droplets and define to trac the particle diamaeter, temperature and weighting factor, e.g.\n",
+    "* `PART`, define the particle species for the water droplets and define to track the particle diamaeter, temperature and weighting factor, e.g.\n",
     "\n",
     "  ```\n",
     "  &PART ID='water droplets', \n",