Year 7 Science · Unit 3 · Lesson 1
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank. Each word is used at most once. Two words are not needed: cross them out.
Every force has a size, called its , and a . Because you need both of these to describe a force, a force is called a . In a force diagram, each force is drawn as an . A arrow stands for a bigger force. A force only acts while the two objects are touching.
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. Holding a small apple up against gravity takes a force of about 1 N.
Correct it:
2. Gravity can only pull on an object that is touching the ground.
Correct it:
3. Force is measured in kilograms (kg).
Correct it:
4. A balloon rubbed on a jumper can pull small pieces of paper toward it without touching them.
Correct it:
5. More than one force can act on the same object at the same time.
Correct it:
1. A force can change an object in four ways. Name all four.
Sort it
For each force, ask “Is anything touching at all?” Then write it in the correct box. The boxes do not hold the same number of items.
Contact force
Non-contact force
2. A book rests on a table. Draw the book as a box. Add a labelled arrow for each force acting on the book, and write C (contact) or NC (non-contact) beside each label. Make the arrow lengths show how the two forces compare.
Read the data: do these estimates make sense?
Scenario
Four students each estimated the size of one force. Their estimates are in Table 1.
| Force | Estimate (N) | C or NC? |
|---|---|---|
| P. Your hand holding up a small apple | 1 | |
| Q. Earth’s gravity pulling down on a school bag full of books | 65 | |
| R. Your hands pulling a loaded wheelie bin along the footpath | 2 | |
| S. A magnet pulling a paper clip across a desk | 0.1 |
Source: made-up estimates for this worksheet.
3. Fill in the last column of Table 1 (C or NC) for all four rows.
4. One estimate in Table 1 cannot be right. Which one? Use another row of the table to explain how you know.
5. Oscar says: “When the wind pushes a yacht’s sail, that is a non-contact force, because I can’t see anything touching the sail.” Explain whether Oscar is right. Then name one other force acting on the yacht, say whether it is contact or non-contact, and give its direction.
Fill the gap
magnitude; direction; vector; arrow; longer; contact. Not used: kilogram, shorter.
True or false
1. True. 2. False: gravity is non-contact; it also pulls a falling ball or the Moon. 3. False: force is measured in newtons (N); kilograms measure mass. 4. True. 5. True.
Question 1
Start a still object moving; stop a moving object; change its direction; change its shape. Two or three correct = 1; all four = 2. [2 marks]
Sort it
Contact: a dog tugging on its lead; wind pushing a kite (air particles hit it); sandpaper rubbing wood; a trampoline pushing a jumper up; a paddle pushing water. Non-contact: a magnet pulling a pin from 2 cm away; Earth pulling a falling netball; a rubbed comb lifting paper bits; Earth pulling on the Moon.
Question 2
Arrow pointing down from the book labelled gravity (or weight), NC (1). Arrow pointing up labelled normal force (the table pushing up), C (1). The two arrows are the same length, because the forces are the same size (1). [3 marks]
Read the data: do these estimates make sense?
3. P: C. Q: NC. R: C. S: NC. Two or three correct = 1; all four = 2. [2 marks]
4. R, the wheelie bin at 2 N (1). 2 N is only about the force to hold up two small apples (row P); dragging a loaded bin clearly needs far more (1). [2 marks]
Question 5
Marking guide: 1 Oscar is wrong; 1 wind is moving air, and air is matter (made of particles); 1 the air particles hit the sail, so the wind touches it and is a contact force; 1 the test is “is anything touching at all?”, not “can I see what is touching?”; 1 another force with type and direction: gravity, NC, down; or water pushing up on the hull, C, up; or water drag, C, backward. [5 marks]
Model answer: Oscar is wrong. Wind is moving air, and air is matter: its particles hit the sail, so wind is a contact force. The test is “is anything touching at all?”, not “can I see it?”. Gravity also acts on the yacht: a non-contact force pulling it down.
Common error: calling a force non-contact because the thing touching (air or water) cannot be seen.