10

4. Sinking and floating: Displacement 23

5. How things are kept from toppling over:
Stability 29

2. MOLECULAR ATTRACTION 36

6. How liquids are absorbed: Capillary attraction 36

7. How things stick to one another: Adhesion 41

8. The force that makes a thing hold together:
Cohesion 44

9. Friction 49

3. CONSERVATION OF ENERGY 57

10. Levers 57

11. Inertia 66

12. Centrifugal force 72

13. Action and reaction 77

14. Elasticity 82

4. HEAT 88

15. Heat makes things expand 88

16. Cooling from expansion 94

17. Freezing and melting 96

18. Evaporation 100

19. Boiling and condensing 107

20. Conduction of heat and convection 116

5. RADIANT HEAT AND LIGHT 122

21. How heat gets here from the sun; why things
glow when they become very hot 122

22. Reflection 129

23. The bending of light: Refraction 136

24. Focus 142

25. Magnification 150

26. Scattering of light: Diffusion of light 158

27. Color 161

6. SOUND 174

28. What sound is 174

29. Echoes 183

30. Pitch 185

7. MAGNETISM AND ELECTRICITY 190

31. Magnets; the compass 190

32. Static electricity 196

8. ELECTRICITY