Science g8 front matters tg

1. 8
Teacher’s Guide

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Science – Grade 8
Learner’s Material
First Edition, 2013
ISBN: ___________
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Development Team of the Learner’s Material
Authors: Pia C. Campo, May R. Chavez, Maria Helen D.H. Catalan, Ph.D., Leticia V.
Catris, Ph.D., Marlene B. Ferido, Ph.D., Ian Kendrich C. Fontanilla, Ph.D., Jacqueline
Rose M. Gutierrez, Shirley R. Jusayan, Michael Anthony B. Mantala, Cerilina M.
Maramag, Marie Paz E. Morales, Eligio C. Obille, Jr., Digna Paningbatan, Genevieve
Faye Pasamonte, Ma. Dulcelina O. Sebastian, Rolando M. Tan, and Rodolfo S. Treyes,
Ph.D.
Reviewers: Ernelea P. Cao, Ph.D., Josefina Ll. Pabellon, Ph.D., Ma. Cristina D.
Padolina, Ph.D., Risa L. Reyes, Ph.D., and Merle C. Tan, Ph.D.
Illustrators: Alvin J. Encarnacion, Ma. Laura V. Ginoy, Rizaldo Ramoncito S. Saliva,
Andrew F. Torres
Layout Artist: Cecile N. Sales

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Page
Module 1. Forces and Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Activity 1: Forces on objects at rest . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Activity 2: Balance of forces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Activity 3: Investigating inertia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Activity 4: Force and acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Activity 5: Action-Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Module 2. Work and Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Activity 1: Is there work done? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Activity 2: Rolling toy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Activity 3: How POWER-ful am I? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Module 3. Heat and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Activity 1: Explaining hotness or coldness . . . . . . . . . . . . . . . . . . . . . 28
Activity 2: Dye in water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Activity 3.1: What happens when ice melts? . . . . . . . . . . . . . . . . . . . . 31
Activity 3.2: What happens to the temperature of water as it boils?. 33
Activity 4: What is the relationship between the mass of a material
and the amount of heat it can transfer?. . . . . . . . . . . . . . . . . . . . . . . . 33
Activity 5: Comparing heat capacities . . . . . . . . . . . . . . . . . . . . . . . . . 34
Module 4. Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Activity 1: Current and voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Activity 2: Current and resistance . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 40
Activity 3: What’s the connection? . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Activity 4: Stay safe! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Module 5. Sounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Activity 1: The dancing salt and the moving beads!. . . . . . . . . . . . . . . 51
Activity 2: Characteristics of waves: Comparing longitudinal and
and transverse waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Activity 3: Sound race… Where does sound travel fastest? . . . . . . . . 52
Activity 4: Chimes… Chimes… Chimes… . . . . . . . . . . . . . . . . . .. . . . . . 52
Activity 5: Faster sound… In hotter or cooler? . . . . . . . . . . . . . . . . . . . 53
Activity 6: Reflecting and refracting sound. . . . . . . . . . . . . . . . . . . . . . 53

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Module 6. Colors of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Activity 1: Refraction of light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Activity 2: The colors of the rainbow . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Activity 3: Red versus violet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Activity 4: Which color has the MOST energy? . . . . . . . . . . . . . . . . . . 61
Activity 5: The color spectrum wheel revisited . . . . . . . . . . . . . . . . . . 61
Module 1. Earthquakes and Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Activity 1: A fault-y setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Activity 2: Stick ‘n’ slip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Activity 3: Stick ‘n’ shake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Activity 4: Where does an earthquake start . . . . . . . . . . . . . . . . . . . . . 77
Activity 5: Tsunami! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Module 2. Understanding Typhoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Activity 1: Plotting the PAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Activity 2: Tracking a tropical cyclone . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Activity 3: Dissecting a tropical cyclone . . . . . . . . . . . . . . . . . . . . . . . . 99
Module 3. Comets, Asteroids, and Meteors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Activity 1: What happens when a comet or an asteroid hits Earth . . 105
Activity 2: Meteoroid, meteor, and meteorite:
How are they related?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Activity 3: Do superstitions about comets, asteroids,
and meteors have scientific basis? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Module 1. The Particle Nature of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Activity 1: Which is matter, which is not? . . . . . . . . . . . . . . . . . . . . . . 119
Activity 2: What is matter made of? . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Activity 3: Are the particles of matter moving?
What is between them? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

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Activity 4: What changes take place when water is left in an open
container? In a closed container? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Activity 5: What changes take place when water
is heated or cooled? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Activity 6: What changes take place when ice turns
into liquid water? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Module 2. Atoms: Inside Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Activity 1: “Charge” it to experience! . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Activity 2: The big difference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Activity 3: Small but terrible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Activity 4: What’s in a number?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Module 3. Periodic Table of Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Activity 1: Tracking the path and constructing the Periodic Table . . . 147
Activity 2: Metal… Metal: How reactive are you? . . . . . . . . . . . . . . . . 151
Appendix: Element Cards for Activity 1 . . . . . . . . . . . . . . . . . . . . . . . . 155
Module 1. Biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Activity 1: What’s in a name? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Activity 2: How do bacteria in yogurt look like? . . . . . . . . . . . . . . . . . . 173
Alternate Activity: How do bacteria in fermented milk look like. . . . 174
Activity 3: What can you do to prevent dengue?. . . . . . . . . . . . . . . . . 182
Activity 4: What is the importance of biodiversity to ecosystems . . . 186
Activity 5: I create the future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Module 2. Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Activity 1: How do you indentify the components
of a food chain in an ecosystem? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Activity 2: Making food webs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Activity 3: Meat eaters vs. plant eaters . . . . . . . . . . . . . . . . . . . . . . . . 203

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Module 3. The Digestive System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Activity 1: Part A. A gusty game . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Activity 1: Part B. A sweet break! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
Activity 2: How do enzymes affect digestion? . . . . . . . . . . . . . . . . . . . 211
Activity 3: How does pH affect enzyme activity? . . . . . . . . . . . . . . . . . 213
Activity 4: A journey into the digestive system . . . . . . . . . . . . . . . . . . 214
Module 4. Nutrition and Wellness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Activity 1: Am I eating right? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Activity 2: What happens when nutritional needs
are not adequately met? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Activity 3: Using essential concepts in nutrition
to planning a menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Module 5. Cellular Reproduction and Genetics . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Activity 1: Observing mitosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Activity 2: Comparing mitosis and meisosis . . . . . . . . . . . . . . . . . . . . . 224
Activity 3: Tossing coins and probability . . . . . . . . . . . . . . . . . . . . . . . 225
Activity 4: Comparing genotypic and phenotypic ratios
for a typical Mendelian trait . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Activity 5: Filling up the Punnett square for a dihybrid cross . . . . . . 227
Activity 6: Phenotypes and genotypes in incomplete dominance. . . . 229
Activity 7: Inferring genotypes of ABO blood types based
on the parental blood types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229