Safety Alert
As an educator you are responsible for the implementation of the activities found on this site. You must have safety procedures and rules established for you classroom and make sure all of the students follow the rules to ensure a safe environment. South Dakota Public Broadcasting cannot in any way be responsible or liable for any injury as a result of using the activities. Use the activities you feel are appropriate and safe for your individual class. Have fun and stay safe.

Questions, comments or ideas for Kids Quest can be e-mailed to Edservices@sdpb.org

It is common knowledge that all kids love to play. Unfortunately, some of the students you have in the classroom are not as thrilled about math, language arts or science class. Their minds may be on recess or a television show they watched the night before. The activity that follows is a very fun and easy supplement to bring your class alive without straying from learning. The kids will learn and have fun.

Activity:
  The focus of the following activity examines the affect differences in gravity have on weight. Weight and mass are very similar but there are differences in there meaning. I have included a clip below to help explain the topic. This is a challenging concept for children to understand. Weight is a measure of how heavy something is. Weight includes the effect of gravity pulling an object toward the center of the earth. Simply stated mass is a measure of how much matter or stuff an object has inside of it. Gravity has no effect on the mass of an object. The video clip below shows the difference between weight and mass. The Kids Quest episode "Fill Your Head with Space” explains some of the concerns of weightlessness and gives the solutions NASA used to overcome them. For your convenience, all of the Kids Quest episodes can be viewed on line at http://www.sdpb.org  Click on the NASA web sight to view a video on line called Space Basics. The video will explain the location of the space shuttle during a normal orbit. Also, weightlessness is explained. http://quest.nasa.gov/space/teachers/liftoff/basics.html

 Watch the Science Sample Clip  (7 min)

Materials per group:

Hammer
1 8' - 2x4 board
1 12”x12”x1” board
2 long nails as fulcrum
10-20 lb. bag of potatoes (note: Rocks may work better and they are less expensive)
6' rope to attach sacks (optional)
rubber tub
fishnet sack (note: garbage sacks or gunny sacks may work)
1 electric balance
graph paper /data paper (1 for each student)
goggles (1 per student)

note: Amounts of material may vary depending on your class size.

Procedure:

Introduction of topic (space) (1-2 class periods)
1. Watch Kids Quest " Fill Your Head With Space”.
2. Cover information in your science text about scientific method.
3. Visit educational web sites about space and gravity.

http://quest.nasa.gov/space/teachers/liftoff/basics.html
http://www.pbs.org/wgbh/nova/search-results.html?q=space

Process:

1. The activity involves the making of a balance. I will explain one way of completing the lab below. The lab setup can be larger or smaller to fit your needs. Your students can use their imaginations to help figure out different ways to complete the lab. This activity is a perfect lab to use to help students understand the basics of the scientific method. The problem is designing a balance out of everyday items to test the effect of buoyancy of water on the weight of objects. The number of steps completed for the scientific method varies depending on which book you use. Below are some sites which explain the scientific method in detail. Also, you will find an simple example shown below.
http://biology.clc.uc.edu/courses/bio104/sci_meth.htm
http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/AppendixE.html

2. I suggest the teacher should complete the building of the balance. The students can help but it should be under the teacher's direct supervision. Use the pictures below as reference for the steps to follow. The 2 long nails should be driven through the 1 inch board to produce a fulcrum for the 8ê 2x4. The nails must be sturdy to hold large amounts of weight. (diagrams 1 and 2). The 2x4 should be centered on the nails (fulcrum). This will produce a simple 1st class lever, which will be used as your balance (diagram 3). The sacks should be placed on the ends of the board. (I admit this is a lot of work but the kids will love it. Also, you can use it forever because teachers can never afford to retire.) The construction is complete. Once the lever is built, it can be used for different labs.

Fig 1 Fig 2 Fig 3

3. The 10-20 lbs. of potatoes or rocks should be divided evenly and placed in the two-fishnet sacks. The sacks should be tied to the balance and allowed to hang. The balance should be level. Move the potatoes or rocks if needed to level the balance. Place a small beach ball in the sack that will be lowered into the water.

4. Take the large tub and fill it with water. Both sacks should still be attached to the balance. Place one of the sacks in the water. The buoyant force of the water will push up part of the weight. Now remove the potatoes or rocks from the other side until the system is balanced. The weight of the potatoes or rocks removed should be measured using an electronic bathroom scale or science balance. Note: You may not have a balance so you could count the number of rocks or potatoes removed. This will equal the buoyant force of the water. Record this amount on the data sheet. (note: Rocks may be better because they are usually more dense resulting in less material used.)

5. Note: This can be a frustrating step. I have used fishnet before and tied it into the shape of a sack. This allows the water to flow in between the potatoes. Then I placed a small, deflated beach ball in the sack under the potatoes or rocks. Small amounts of air can be blown into the ball increasing the buoyancy. The potatoes placed in the water will be pushed up because volume is increased. The extra air will act like a small life jacket. Repeat step 4. Continue to add more air to the sacks. Repeat step 4 after each small amount of air is added. You should have approximately 10 readings. (2nd option: A garbage sack or baggy could be used for the air, but the amount introduced is harder to control.)

6. The activity is perfect because the students can visually see the effect of the buoyant force on the weight of the object. This is very similar to the effect of weightlessness an astronaut would experience in orbit. The mass is the same, but the weight appears to change. The easiest way to experience a space walk is going swimming in a pool. Cool!!!

7. With your help, the students can construct the graph. A graph could be made comparing the data sample with the apparent weight loss.

8. The activity can be modified to meet your needs.

9. This lab takes practice and patience. It may take a few times to master a technique that works for you. The data may not be perfect the first few times. That is ok because the students will still understand buoyancy and have fun.

(example graph - can be completed on paper)
(does not represent actual data)

State Standards:
If completed correctly, the following standards are used in the activity above. More standards could be used by including spin-offs of the activity. For example, a paper could be written about Archimedes' Principle and its affect on weight. http://www.state.sd.us/deca/OCTA/contentstandards/index.htm
Number indicates standard number

FIFTH GRADE ALGEBRA STANDARDS- THE STUDENT WILL:
8. analyze tables and graphs to identify properties and relationships.
9. represent situations and number patterns with concrete materials, tables, graphs, verbal rules, and algebraic notation. (could expand the data)

FIFTH GRADE MEASUREMENT STANDARDS - THE STUDENT WILL:
7. use appropriate tools to measure length, weight, temperature, volume, and area.
11. use and evaluate strategies to make measurement estimates.

FIFTH GRADE NUMBER SENSE STANDARDS- THE STUDENT WILL:
13. solve problems using non-routine strategies. (using the constructed balance as estimation)

FIFTH GRADE PATTERNS, RELATIONS, AND FUNCTIONS STANDARDS - THE STUDENT WILL:
2. analyze how change in one variable causes a change in another. (example: holding area constant and changing length and width) (increased surface area - increased buoyant force)
6. use information from a graph or equation to answer questions about a problem situation or to create a "story".

FIFTH GRADE STATISTICS & PROBABILITY STANDARDS- THE STUDENT WILL:
1. collect, organize, and display data in a variety of forms.

FIFTH GRADE NATURE OF SCIENCE STANDARDS- STUDENTS WILL:
2. identify and model characteristics of scientific thinking. (designing a balance with class)
3. explain how scientific theory, hypothesis generation, and experimentation are interrelated.
6. formulate hypotheses based on cause and effect relationships and use observed patterns to make predictions.
7. make predictions, utilize observations, and draw conclusions.
8. define variables that must be held constant in a specific experimental situation.
9. collect, record, and report data using the appropriate graphical representation. (example: graphs, charts, and diagrams)
10. recognize numerical data that are contradictory or unusual in experimental results.
11. use appropriate scientific equipment for investigations.
12. use proper safety procedures in all investigations.

FIFTH GRADE PHYSICAL SCIENCE STANDARDS- STUDENTS WILL:
9. explain that every object in the universe has mass and therefore gives rise to a gravitational force on every other object.
11. analyze the structure and design of simple and complex machines to determine how the machines make work easier. (expand on the 1st class lever)

Resource: South Dakota Department of Education Content Standards.