Forces at work

Resource Info

Basic Information

Force is one of the most important aspects in the discipline of science and it is essential that we have at least a basic understanding of this concept. This activity explores it for young learners.

Duration: 
03 hours 00 mins
Introduction: 

What keeps our feet firmly on the ground, birds in the air and boats afloat water? A variety of forces.These forces can be best understood through experiential learning. The activities suggested here will enable students to experience and analyze various forces at work through observations and experimentation. The activities in this article will allow young students to experience the joy of discovering for themselves the answers to several phenomena they see around them.

Objective: 
Aims & Objectives
  • To learn about force through hands-on activities. 
  • To conduct experiments and make observations regarding the principles of forces at work. 
  • To develop scientific spirit in children.
  • To build problem-solving skills.
  • To encourage creativity.
Activity Steps: 

Forces at work
To make life around us possible, there are several forces at work. There are natural forces like the gravitational force or the pumping of the heart and there are forces that are consciously exerted by us. Children are constantly seen pulling each other, pushing objects, blowing air into balloons, or making paper boats which float on water. What we need to do is to create opportunities for children to explore ‘forces’ and arrive at a scientific understanding of these goings- on around them.

First provide the children with plenty of opportunities to simply observe the effects of forces upon objects. A few actions such as dropping an eraser, pushing a table, and blowing a balloon could be demonstrated in front of the children. Also introduce the required vocabulary for studying forces such as going fast, slowing down, changing direction, upward push. etc.

Rolling down

An inclined plane is a useful tool to study the ‘force’ of a rolling object. The children could easily observe that all objects do not roll on an inclined plane. Divide the children into equal groups. Give them some objects such as marbles, erasers, etc.

Ask the groups to predict the rolling ability of each object. The list can have three columns.

  • Will roll
  • Will not roll
  • Will roll if placed in a certain direction or angle.

 Place the inclined plane as illustrated in the picture. Allow the children to roll the given objects on the plane. After the exercise, ask them to compare their results with their predictions.
 Find out if the objects that do not roll can be made to roll if placed in a particular direction. For example, a pencil will roll if placed horizontally rather than vertically.
 The children may notice that some objects travel faster and some, slower. Can they think of any reason for their observations?
 Alter the position of the inclined plane. How do the objects roll if the plane is raised higher or lowered down?
 The force with which an object rolls down an inclined plane is not only determined by the shape of the object but also by the surface of the plane. Place sandpaper on the inclined plane and ask the children to repeat the experiment. They can compare their results with the results of the previous experiment and try to give reasons for the differences if any.
 Most children enjoy playing on a slippery slide. It could be an ideal example to teach forces. Divide the children into two or more groups. Ask one group to go down the slide. Let the other children make some observations of the activity. Let them answer a few queries such as who slid down the fastest? Who stopped in the middle? Who was scared of slipping down? Was the surface slippery or rough? The children will realize that the sliding speed depends upon the force we exert. Ask the children whether they can slide down if the slide is make of stone or rubber. Now make the children sit on a cardboard piece (biscuit or a soap box which is available in any general store) and ask them to slide down. How easily can they slide down now? Can they slide as fast as before? If not what could be the reason for this according to them.
 While it is enough for the children of classes II and III to simply observe the forces at work, the children of class IV could be told the ‘how and why’ of the activities. For example, the forces of gravity could be explained in brief. Gravity is a force which pulls all objects down towards the earth. This why things fall, or travel down a slide.

All fall down
The materials or resources required for this experiment are:
Feathers
Papers
Leaves
Stones
Cello tapes

Marbles

Take care not to use objects which may hurt the children.

Discuss the nature of the experiment with the children. Tell the children that they will have to drop the objects from a given height and note the way in which they fall to the ground.

 First let the children predict the falling speed of each object. Will the feather fall as quickly as the stone? Let the objects be placed in the order in which the children predict they will fall to the ground.
 Allow each group to carry out the experiment. Provide a stop clock for noting down the speed at which each object reaches the ground. Let them compare the results with their predictions. If it is difficult to time the falling speed of each object, the children can simply observe which of the objects fall quickly and which slowly.
 Can the children suggest reasons for the different speeds at which each object falls to the ground?
 Does wind or air have anything to do with the way the objects fall to the ground?
 Ask the children to drop a feather when the air is still or moderate. How does the feather fall when there is gush of air?

Try another experiment, and this time note which objects sink and which float. The resources you will need for this experiment are:

pencils
erasers
needles
small pieces of wood
paper boats
plastic clips
small stones
plasticine

Ask children to predict the floating capacity of each object when placed in a trough of water. The object could be divided into two categories
Will sink
Will float

Place a trough of water in a location where spilt water can be cleaned up. Ask the children to place the objects in the trough one by one and note their observations. They can compare their recordings with their predictions.

For the children of class IV, one can even explain that water exerts a push force on the objects on its surface. If the object is heavier than water, it will sink, otherwise it will float. A stone placed in water will sink, while a plastic clip will float.

Surely the children would have noticed that a ship, which is huge, does not sink in water. Tell them that some heavy objects can be made to float by changing their shape. Get the children to notice that the shape of an object determines its floating or sinking capacity. The larger the volume of the object, the more is its floating capacity. Hence a ball of plasticine sinks while a boat made of plasticine floats on water. In ancient days boasts were made from material lighter than water such as wood, bundles of reeds and bark of wood. Now we have boats made of plastics, fiber glass and metals such as aluminum and steel.

Place a ball of paper and a sheet of paper on water. The ball of paper floats while the sheet of paper becomes wet and sinks. Let the children understand that air within the ball enables the ball to float. Here is an activity with a difference. Can the objects which float be used to support the objects which sink? The activity may seem complex, but it will enable us to initiate problem solving and creative thinking in the children.

Ask the children to find an object that floats to support an object that sinks. They will realize that not all objects that float can keep the sinking objects afloat. The supporting capacity of an object is largely determined by factors such as weight, shap,e and amount of air the objects can hold.

Experiential learning demands lot of practice. So the children should be given the opportunity to repeat the activities or experiments several times under many circumstances. It is necessary to conclude each session with some kind of summary. As a final note, remember that the children will surely surprise you will their abilities if allowed to demonstrate rather than tell about a subject.

Note for the teacher: Pelicans spend a lot of time floating on water. They can float because of the air that is trapped between their fine feathers.

Water striders are insects that ‘walk’ on water. Their feet have tiny hair, which help to spread their weight, thus preventing them from sinking in the water. They feed on insects found on the surface of the water.

 

This article is based on an article in Junior Education, April 1991 and it first appeared in Teacher Plus, Issue No.51, November-December 1997 and has been adapted here with changes.

Comments

rakeshcarpenter's picture

Activity Discription is good.

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