Respond to comments from @dopplershift

core/datetime/datetime.ipynb

@@ -101,7 +101,7 @@
     "import time as tm\n",
     "```\n",
     "\n",
-    "We can now reference the `datetime` module (alaised to `dt`) and `datetime` object unambiguously"
+    "We can now reference the `datetime` module (aliased to `dt`) and `datetime` object unambiguously."
    ]
   },
   {
@@ -464,8 +464,8 @@
     "print(f\"The time between high and low tide is {tide_duration}.\")\n",
     "print(f\"The current high tide is {high_tide}.\")\n",
     "print(f\"The next low tide is {next_low_tide}.\")\n",
-    "print(f\"The next high tide  {next_high_tide}.\")\n",
-    "print(f\"The tide length is  {tide_length}.\")\n",
+    "print(f\"The next high tide {next_high_tide}.\")\n",
+    "print(f\"The tide length is {tide_length}.\")\n",
     "print(\"The type of the 'tide_length' variable is {}.\".format(type(tide_length)))"
    ]
   },
@@ -493,9 +493,39 @@
     "When you create `datetime` objects in Python, they are so-called \"naive\" which means they are time zone unaware. In many situations, you can happily go forward without this detail getting in the way of your work. As the [Python documentation states](https://docs.python.org/3/library/datetime.html#aware-and-naive-objects):\n",
     ">Naive objects are easy to understand and to work with, at the cost of ignoring some aspects of reality. \n",
     "\n",
-    "However, if you wish to convey time zone information, you will have to make your `datetime` objects time zone aware. In order to handle time zones in Python, you will need the third-party [pytz](https://pypi.org/project/pytz/) module whose classes build upon, or \"inherit\" in OO terminology, from the `tzinfo` class. You cannot solely rely on the Python Standard Library unfortunately. \n",
+    "However, if you wish to convey time zone information, you will have to make your `datetime` objects time zone aware. The `datetime` library is able to handle conversions to UTC:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "naive = dt.datetime.now()\n",
+    "aware = dt.datetime.now(dt.timezone.utc)\n",
+    "print(f\"I am time zone naive {naive}.\")\n",
+    "print(f\"I am time zone aware {aware}.\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The time difference between `naive` and `aware` will depend on what time you're in when you run this code!\n",
+    "\n",
+    "In the code above, we used `dt.timezone.utc` to initialize the UTC timezone for our `aware` object. Unfortunately at this time the Python Standard Library does not fully support initializing `datetime` objects with arbitrary time zones, or conversions between different time zones. "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Full time zone support with the `pytz` module\n",
+    "\n",
+    "For improved handling of time zones in Python, you will need the third-party [pytz](https://pypi.org/project/pytz/) module whose classes build upon, or \"inherit\" in OO terminology, from `datetime` classes. \n",
     "\n",
-    "Here, we create time zone naive and time zone aware `datetime` objects:"
+    "Here, we repeat the above exercise but initialize our `aware` object in a different time zone:"
    ]
   },
   {