# Astronomy Unit Study: Unit Five – Planet Earth

Welcome to unit five of our astronomy studies!  Lately, we have been learning all about Planet Earth. As before, we have been using Apologia’s Exploring Creation with Astronomy. Also, I have access to Everyday Astronomy from School House Teachers, as well as lots of bits and pieces I used with my older ones that I have collected over the years:

I read the Planet Earth chapter from the Astronomy text and the made notes, experiment sheets. copywork and a few mini-books:

### Perfect Atmosphere: A Visual Representation of the Composition of Air on Planet Earth

The girls painted a bottle of air to show the approximate volumes of molecules found in air:

### Perfect Land: Creating a (Very Imperfect) Model of Planet Earth

We created a very messy (and not terribly accurate!) model of the earth using marshmallows, crispies, and sweets.  First the girls placed a sweet (the inner core) inside two pink marshmallows (the outer core):

We then melted the marshmallows and added the crispies:

And this is when it got very messy as the girls attempted to create some mantle:

Hmmm.  This may not have been such a hot idea!  We did eventually manage to get form the marshmallow stuff (and therefore the mantle) around the inner and outer core….then we covered it with melted chocolate to create the crust:

Yes, I know what you’re thinking….wow, what an incredible likeness to Planet Earth!

Even more so when you open them (especially given you can’t technically open the actual earth, so these could indeed be very accurate….):

I astound myself sometimes!

### Perfect Atmosphere: A Demonstration of how Essential the Earth’s Air Pressure is for Maintaining Life on Planet Earth

I asked the girls to attempt to blow up a balloon in a bottle.  They tried and they tried….to no avail:

The reason for this is that the air pressure on the inside increases to such an extent that it is impossible to blow it up any further than demonstrated by the girls, even though the bottle is seemingly empty.  I placed a straw into the bottle down the side of the deflated balloon

The girls then attempted to blow it up a second time.  This time it was much easier:

The reason for this is that as the balloon becomes slightly larger it exerts enough pressure on the air inside the bottle that it shoots out through the straw.  This has the knock-on affect of decreasing the air pressure inside the bottle, thus allowing the balloon to be filled with an equal amount of air.  With regards to earth, the air pressure is perfect, allowing the water to stay in the oceans, humans to walk on the surface of the earth and easy breathing for all living things:

### Perfect Rotation: A Demonstration of how Planet Earth Rotates Around the Sun

The explanations in the photo are perfect, so I shall just leave you with them:

Just imagine a solar system without the sun’s gravitational pull ensuring the earth stays within ats orbital path.  It would be utter chaos!

### A Demonstration of How Telescopes Magnify

The girls popped some beads into the bottom of an otherwise empty jar and placed some cling film on top, fastening in place with an elastic band:

They added water to the loose clingfilm, creating a makeshift lens.  The water acts as a lens and magnifies the beads at the bottom of the jar.  Can you see the difference?

### Building a Model of the Hubble Space Telescope, the Largest Telescope in the World:

This was an activity from an astronomy kit I bought for pennies at a charity shop.  Abigail put the Hubble Space Telescope together:

It really worked, although not quite to the extent of the actual Hubble telescope  🙂

### Reviewing the Solar System:

We made a model of the solar system (again!):

Reviewed the planets we’d studied already:

### For more Astronomy posts click on the following links:

1) Astronomy Presentation from my teens when they were younger:

5) Astronomy Unit Four: Planet Venus

## 3 comments on “Astronomy Unit Study: Unit Five – Planet Earth”

1. This seems like so much fun. I’m sure they learned a lot with all those activities 🙂

2. Our rice crispy planet was quite messy too! Your two littles are looking a bit more grown up.

3. I love your model of the atmosphere, that’s a cool idea.

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