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Why is there sand at the beach?

Work of Water Unit
Lesson 3 of 6
Rocks, Sand, & Erosion
4.8 (22311 reviews)
Lesson narration:
English Spanish
Scroll for prep
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DISCUSS (1 of 2):

Why do you think the sand is purple?

DISCUSS (2 of 2):

Imagine you were at Pfeiffer Beach. How could you look for clues to help you solve the mystery of where the purple sand comes from?

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DISCUSS:

Can you think of a way tiny pieces of these rocks could move from the mountains all the way to the beach?

Hint...

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DISCUSS: What do you think would happen if the rocks in the river crashed into each other? Could this explain how there’s sand at the beach?

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Slide Image
Slide Image

ocean


1 of 15

a large area of salt water that covers the Earth
Slide Image

beach


2 of 15

land next to a large area of water, often covered in sand
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microscope


3 of 15

a tool used to see very tiny things up close
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sand


4 of 15

very tiny pieces of rock, such as what you often see on the ground at a beach
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pebble


5 of 15

a small rock, usually with smooth edges
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rock


6 of 15

a solid natural material that is found on and under the surface of the Earth
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boulder


7 of 15

a large rock
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mountain


8 of 15

a high area of land with steep sides
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slope


9 of 15

where one side is higher than the other
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steep


10 of 15

something that is very high up on one end and very low at the other end
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river


11 of 15

a long, thin area of water that flows

flow


12 of 15

to move along
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erosion


13 of 15

when tiny bits of rock are moved from one place to another
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downstream


14 of 15

toward the direction that water in a river or stream flows
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model


15 of 15

a pretend version of something that scientists use when the real thing is too big, small, or complicated to work with
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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Exploration
kids at the beach by Image used under license from Shutterstock.com: bikeriderlondon
white sand beach by Image used under license from Shutterstock.com: Rob Marmion
girl on the beach by Image used under license from Shutterstock.com: ori-artiste
sand castle by Image used under license from Shutterstock.com: Kris Wiktor
Southwick Beach State Park by Easchiff
hand in sand by Image used under license from Shutterstock.com: kasidit
kid at Pfieffer Beach by The Offshore Aquaholic
purple sand by The Offshore Aquaholic
purple sand beach by Carson
kid holding sand by Image used under license from Shutterstock.com: Albina Glisic
footprints on purple beach by Image used under license from Shutterstock.com: mhgstan
hand holding purple sand by Akos Kokai
magnifiying glass by Image used under license from Shutterstock.com: underworld
close up of sand by Image used under license from Shutterstock.com: Mr Twister
zoomed view of sand by Image used under license from Shutterstock.com: AlexussK
green sand beach by Image used under license from Shutterstock.com: Alexander Demyanenko
close up of green sand by Brian W. Schaller
cliffs facing the beach by Image used under license from Shutterstock.com: Noradoa
close up of cliff by Image used under license from Shutterstock.com: jennyt
scuba diver by Image used under license from Shutterstock.com: Rostislav Ageev
Lepidolite (purple rock) by Spirit Rock Shop
purple mountains by Gonzo fan2007
falling rocks sign by Image used under license from Shutterstock.com: Michael Leslie
rock crashing down mountain by Joraj Dason
beach flooding by Muhammad Moolla
fast flowing river by Hayk Arakelyan
rocks flowing down river by Internet Geography
big blue waves by Image used under license from Shutterstock.com: bus109
chair and beach umbrella by Image used under license from Shutterstock.com: Aleks Melnik
clouds by Image used under license from Shutterstock.com: nikiteev_konstantin
mountains sillhouette by Image used under license from Shutterstock.com: Alex Ghidan
ocean concept by Image used under license from Shutterstock.com: Nikita Konashenkov
sand texture by Image used under license from Shutterstock.com: Ursa Major
Rainbow Beach by Cassarazzi
green rock by Image used under license from Shutterstock.com: Helen Cingisiz
hornocal by Lahi
close up of rainbow beach by cordyceps
stream on the beach by Humphrey Bolton
Activity
rushing river in Smoky Mountains by GreatSmokyMountains (© GSMA 2010. All rights reserved.)
turtles by Image used under license from Shutterstock.com: Dmitri Ma
rushing river by fccysf
Credits
Why is there sand at the beach?
Work of Water Unit
Lesson 3 of 6
Rocks, Sand, & Erosion
4.8 (22311 reviews)

Featured Reviews

“The best part was after learning the process of rocks to sand we read Everybody Needs a rock (one of the suggested optional extras) and went rock hunting. It was such a fun activity. My second graders were so engaged and talked about how the small rocks we were finding used to be part of huge boulders. Fun!”
· Libba · Teacher
“The wrap-up, following the activity. The visual process of the bolder breaking down over & over really provided a great picture of erosion and the purple sand was a great way to get students hooked at the beginning. We added a wonder wall where students placed curiosities & questions throughout the video, so we could go back & answer any questions at the end of the unit. Their illustrations & summarizations were totally on point.”
· Diana · Teacher
“The best part was that Mystery Science showed a magnified view of sand. This introduced students to the fact that grains of sand can be many different colors and can come from many different kinds of larger rocks. My 2nd grade science classes used magnifying lenses to make enlarged drawings of individual grains of sand. ”
· · Teacher
“This lesson allowed for every single student to be fully engaged! They passed the ripped pieces of paper to each other and placed them on the paper quickly and excitedly and then FROZE when the visual timer went off! Having the timer included in the lesson was a big help, so I didn't have to use my phone and they could see it!! They have been talking about this lesson for weeks!”
· Bethany · Teacher
“The kids really enjoyed it. It was also easy to get the supplies ready for the activity and it was meaningful to the students. ”
· Kelly · Teacher
“We LOVED this one. The hands-on component with the rain showers and decreasing boulders was such fun for the kids, and an easy demonstration of how sand is formed. Thanks!”
· Linda · Homeschooler
“My students loved this experiment,and they really understood how sand got to the beach and about the color!”
· Cheryl · Teacher
“The short videos were perfect to engage the students and get them talking. They were so excited to learn more about how large boulders became sand. Every student ws engaged!”
· Nina · Teacher
“The students were so engaged. They got the concept since they could actually see the process. Great lesson. ”
· Loretta · Teacher
“The kids loved the hands-on activity. The visual that was built, really helped them to see the process of the boulder being broken down over time. The videoed timers, along with the water sounds, helped too. Very well done presentation. ”
· Jo-Anne · Teacher
“Learning about the purple sand. The activity was engaging and purposeful. The videos were helpful reinforcements of the activity. The students enjoyed learning about the different landforms around the world. The lesson helped the students gain a better understanding of weathering, erosion, and depositioning.”
· Katrina · Teacher
“The lesson was awesome as always! This is the first time in my career that I have felt like a good science teacher.”
· Tracy · Teacher
“They got it! :) YAY!! The way erosion is explained is perfect! The activity was simple and fun but more importantly they understand the concept now. Why is the sand purple? They were thinking pollution. Now they understand that sand is the color of rocks that have been eroded away. YAY! I couldn't be happier with this product! :) Thank you!”
· Joy · Teacher
“Students really enjoyed this lesson. Steps were easy to follow and material easily accessible. Prep time was quick. All level of EL's engaged.”
· Virginia · Teacher
“The children loved the hands on rock erosion activity. It really helped them understand how sand is created.”
· Janae · Teacher
“The students were able to retell and TEACH others about how sand is formed. They also made connections to yesterday's lesson about how rivers are different from other bodies of water because they travel all the way to the ocean. I had an administrator come in for a walkthrough while teaching this lesson and he was so impressed that the students were able to tell him every single part of how sand is formed! They were also able to answer his questions.”
· · Teacher
“The students really understood the process of why there is sand at the beach. The activity of "breaking up the rocks" as you go downstream was really effective. Thanks!”
· Joe · Teacher
“Great! Experiment was very engaging and easy to prepare! Can't wait to do this again next year!”
· Jill · Teacher
“A substitute teacher was here this day. She said that the lesson was very easy to understand and follow and the students were highly engaged. ”
· Heather · Teacher
“The students had many of the ideas and suggestions that where disproved in the video. It made the scenario very "real" to them. A couple made correct predictions so they were feeling very confident!”
· Patsy · Teacher
“I didn't think erosion could be fun for my students. They had a blast tearing up paper and really seemed to understand the concept.”
· Suzanne · Teacher
“Great video and hands-on activity that connected and could easily be referred to thoughout the lesson. Good visuals and language for bilingual/ESL students.”
· Janelle · Teacher
“The videos and the river activity! The students loved it and learned so much about beaches and where they come from.”
· Doreen · Teacher
“Getting to hear why my students thought the sand was purple. They were very creative coming up with answers, but then really did understand why it was purple at the end of the lesson. ”
· Margaux · Teacher
“The visual activities teach the concept so well! And we love the step by step instructions! THANK YOU!”
· Beth · Teacher
“This is a fantastic lesson! The kids had some misconceptions before we began this lesson. The kids now have a great understanding and will remember this well because of the fun activities!”
· Lisa · Teacher
“I love how the explorations stop to ask students to think critically! My second graders were engaged throughout the exploration and came up with some thoughtful explanations! Wonderful job!”
· Karen · Teacher
“Ripping the paper really helped kids see/experience how the rocks change to sand. I love the videos - the timer and directions are built in. Such easy planning and prep for the teacher. ”
· Reene · Teacher
Lesson narration:
English Spanish

Activity Prep

Print Prep
In this lesson, students investigate the effects of rocks tumbling in a river. Based on their observations, they construct an explanation for why there is sand at a beach. In the activity, Rocking the River, students pretend to be a river and tear up pieces of construction paper to model what happens to rocks as they travel along the river.
Preview activity

Vocabulary

Assessments

I have a Mystery Pack

Draw the River Rocks worksheet 30 copies
River (5 sheets) printout Print 8 copies
Colored Construction Paper
24 sheets
Prep Instructions

We suggest students work in groups of four. Homeschool students can work alone.

Prepare “Paper Boulders”

Cut or tear each sheet of construction paper into about 12 pieces. We used a paper cutter to cut many sheets at the same time, making irregularly shaped pieces, but tearing or cutting with scissors will also work.

randomly cut paper

Each group (or single homeschool student) should start with 3 sheets worth of boulders (about 36). We recommend providing plenty of boulders at the beginning so that the students will still have large boulders at the end of the activity. That way, students will be able to see how the sizes of the rocks change as they move downstream.

Standards

Jump to

Exploration

22 mins

Hands-On Activity

30 mins

Wrap-Up

3 mins

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Credits
 
Water Lesson 3: Why is there sand at the beach?

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