Seesaws
This unit comprises 5 stations, which involve the students comparing the weight of two or more objects.
Two of the stations require the students to construct and use a "seesaw" made with shoebox lids and soft drink cans. In the other 3 stations the students will use balance scales and a home-made spring balance. One of the stations is designed to develop the student’s understanding of the conservation of mass.
compare a 2 objects by weight
order 3 or more objects by weight
describe the weight of objects using comparative language, for example, heavier, lighter.
In these stations the students will make direct comparisons between objects using balance and spring scales.
The students will also be encouraged to estimate which object is heavier by holding the objects before using the balance scales.
Comparing the masses of objects is the second stage in developing an understanding of mass. In these stations balance scales and see-saws are used to directly compare the mass of two objects. In addition students will use home-made spring balances to compare the weights of two or more objects.
Young students are influenced by what they see. The shape or the size of an object can easily deceive them. For example, students who do not yet conserve the property of mass will think that if the shape of an object changes then so does its mass.
In one of the stations the students will change the shape of one piece of plasticene and then weigh it to see that the weight has stayed the same.
Station One: See-saws
In this station we work with a partner to make a see-saw using a soft-drink can and a shoe box lid. We then use the see-saw to find objects that are the same weight.
- First make a see-saw.
Stop the soft drink can from rolling by fixing it to the table with tape or put plasticene rolls on each side. - Now see if the students can balance the lid on the can when it is empty.
- Now use the cars and animals to see if you can find things that make the see-saw balance.
- Draw a picture to show some of the things that balanced.
- As the students work ask questions that focus on the way that things balance
How did you make your see-saw?
What are some things you found that balance? Show me.
Have you ever been on a see-saw? What happens?
Station Two: Weighing balls and worms
In this station the students, in pairs, experiment with plasticene or play dough to find that changes in an object’s shape does not change its weight.
- Give each student a ball of plasticene. Tell them that they need to work with a partner.
- Ask them to check that their "balls" are the same weight by using their see-saws.
- If they are different ask them to make them the same by removing some of the play dough.
- Ask the students to make a cat using their plasticene.
Will your cats be the same weight? Why /Why not?
Check on the balance scales. - Ask the students to remake their "cat" into the longest worm they can.
Whose worm is longest?
Whose worm is heaviest? Check?
Why are they the same weight? - Ask the students to make their "worm" into different sized balls.
Whose has made the most balls?
Which ball is the heaviest? Check?
If you both put all your balls together on the seesaw what do you think will happen?
What do you notice? Why is the seesaw balanced? - Ask the students to draw a picture of what they found out.
Station Three: What balances Freddy Frog?
In this station the students experiment to find items that balance Freddy Frog (or an alternative object). The students paste their solutions onto a class chart.
- Set up the balance scales with Freddy Frog in one of the balance buckets.
- Have a collection of different objects at the table for the students to experiment with, for example, linking cubes, pattern blocks, counters, small toys, buttons.
- Ask that the students put their solutions with their name on the chart paper.
- Ask questions that focus on their use of the balance scale.
What happens on the scales when Freddy is heavier?
Do you think that this "car" will be lighter or heavier? Why do you think that? Were you right? - What are some of the things that you found that were the same weight as Freddy Frog?
Station Four
In this station we line objects up in order of weight so that we can work out who goes where in our "tower". We need to have the heaviest at the bottom and the lightest at the top.
- Give the students 4 toys and ask them to put them in order of weight.
- Before using the balance scales ask the students to hold the toys and guess the lightest and heaviest.
- Check guesses with the balance scales.
Were your guesses correct?
Tell me how you put the toys in order? - Ask the students to find another toy or object, which is lighter than the four toys they have ordered.
Did you find a lighter toy on your first guess?
How did you check your guess? - Ask them to find another toy or object which is heavier than the 5 they now have ordered.
Station Five: Bungeys
In this station students use a simple piece of elastic as a bungee and measure how far the elastic stretches to compare the weight of different objects.
- Set up a bungee by tying a piece of elastic onto a bull-clip or a clothes peg. The top of the bungee will need to be attached to something it can hang from, a string suspended tight across the classroom or a metre ruler suspended across two desks would be ideal. There also needs to be a piece of paper behind the bungee, which the students can use to mark how far down the wall the bungee extends
- Have students take one object at a time and attach it to the clip. They then let the objects go, wait till the elastic comes to rest and mark on the paper how far down the object falls.
- Students repeat for all objects and then decide which is heaviest.
Dear Family,
This week we have been comparing the weight of objects using soft drink "see-saws" and bungee strings. We have been encouraging the children to use words such as heavier and lighter to compare the weight of objects.
See-saws and Bungees
At home you might like to make your own "see-saw" or bungee and then use it to compare the weights of small objects.
- Make a see-saw using a soft-drink can, a shoe box lid and some tape.
- Stop the soft drink can from rolling by fixing it to the table with. Use a narrow box lid (or cut a larger one in half)
- See if your child can balance the lid on the can when it is empty.
- Provide your child with small objects (paper clips, beans, coins) to see if they can find combinations that balance. Use the cars and animals to see if you can find things that make the see-saw balance.
Make a bungee by attaching a clip to hat elastic, which is suspended from string.
You can then compare the weight of different toys be seeing how far they stretch the bungee.
Similar Resources
Great Grams
This unit comprises 5 stations which develop our concept of the "feel" of a gram. The stations may be taken as whole class activities or they may be set up as activities that groups of students use throughout the week.
Weighing Stations
In this unit students work at a variety of stations involving practical measuring tasks. Estimation skills and the ability to measure accurately using kilograms and grams are developed.
Supermarket Shopping
In this unit we introduce the kilogram as a standard unit of measurement using the context of Supermarket shopping. We develop our understanding of the "feel" of a kilogram by making our own kilogram weights.
Making Benchmarks - Mass
In this unit we will explore the idea of having Benchmarks of 1 kilogram and 1/2 kilogram or 500 grams to aid in estimating the mass of given objects.
Weighty Problems
This unit comprises 6 stations which involve the students solving problems which involve applying and interpreting aspects of mass. In addition one of the stations introduces the concepts of net and gross mass. The stations may be taken as whole class activities of they may be set up as activities that groups of students use throughout the week.
