Weathering and Erosion of Rock Both weathering and erosion are processes that break rocks into smaller pieces. In erosion, those pieces are carried off.

Weathering and Erosion of Rock

Both weathering and erosion are processes that break rocks into smaller pieces. In erosion, those pieces are carried off by water, wind, or moving ice (glaciers).

How do stones that look like this...

...turn into smooth pebbles that look like this?

Let's see what Bill Nye has prepared to help answer that question.

Bill Nye the Science Guy Pet Rock Theatre

Click picture for video

How long did Grandpa Rock say it took for him to smooth out?

millions of yearsClick picture to check your answer.

Well, we don't have that long! Luckily, there is a mineral with properties that make it easy to simulate erosion. It's one you eat every day.

Any guesses?

It's halite, also known as rock salt. Halite has a hardness of 2.5. It is this property that will allow us to see the results of erosion in minutes, rather than waiting for millions of years.

Rock Salt is a chemical sedimentary rock that forms when ocean water or saline lakes evaporate. It is used in the chemical industry and to melt snow and ice off roads and sidewalks. Some halite is processed for use as a seasoning for food.

In its purest form, the mineral halite is colorless or white.

Impurities can create some interesting colors, though.

Look closely at a piece of rock salt.

In the first section of your recording sheet, draw a picture of the rock salt. Write describing words and phrases next to your drawing. Put the rock salt next to the picture.

You will pour a little water into one of the flasks, then you will swirl the rock salt in both flasks around for 2 minutes.

Before you begin, make a prediction: What will happen to the rock salt in each flask??

Write your prediction on your recording sheet.

Then follow the instructions to complete the activity.