GoalSay that forces can make things start to move or stop, and measure how far a toy goes after pushes of different sizes.
New words
move · to go from one place to anotherstop · to no longer movemeasure · to find out how long or how far something is
Explanation
A force can make a thing start to move. A force can also make a moving thing slow down or stop. A footballer kicks the ball and it starts to roll. A goalkeeper uses a force to stop it. A big push makes a toy car go farther than a small push. To test this we must do a fair test. We change only the size of the push. We keep the same toy car and the same floor. Then we measure how far the car goes. If we record the results in a table, it is easy to compare them.
Push
Distance the car went
small
40 cm
medium
90 cm
big
?
Worked examples
A girl kicks a ball, and it starts to move. Then a boy puts his foot on the ball, and it stops.
Nodira pushes her little brother on a swing, and the swing starts to move. When it is time to go home, she holds the seat gently and the swing stops.
Yuki’s results: small push 40 cm, medium push 90 cm, big push 150 cm. The bigger the push, the farther the car went.
Class activity
Push test (with an adult): use a small toy car on a smooth floor. Give it a small push, a medium push and a big push. Predict which will go farthest. Measure how far each push takes the car, using a ruler or a paper strip, and write the results in a table. Do each push three times and use the middle result. What did you change? What did you keep the same?
Practice
1
Name two things a force can do to a toy car.
It can make it start moving, and it can make it stop (or slow down).
2
Look at the chart. How far did the car go with the big push?
120 cm.
3
Sara pushes the car harder each time. Which two things must stay the same in a fair test?
For example: the same toy car and the same floor.
4
A goalkeeper catches a ball that is rolling towards the goal. What did the goalkeeper do to the ball?
